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  • 1. Apelqvist, G
    et al.
    Wikell, C
    Carlsson, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology.
    Hjorth, S
    Bergqvist, P B F
    Ahlner, Johan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Bengtsson, Finn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Psychiatry. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Psychiatry.
    Dynamic and kinetic effects of chronic citalopram treatment in experimental hepatic encephalopathy2000In: Clinical neuropharmacology, ISSN 0362-5664, E-ISSN 1537-162X, Vol. 23, no 6, p. 304-317Article in journal (Refereed)
    Abstract [en]

    Chronic hepatic encephalopathy (HE) is a neuropsychiatric syndrome that arises in liver-impaired subjects. Patients with HE display various neuropsychiatric symptoms including affective disturbances and may therefore likely receive treatment with novel thymoleptics like citalopram (CIT). The simultaneous pharmacokinetic and pharmacodynamic outcome of the commonly used serotonin-selective thymoleptic drugs in liver-impaired subjects with pending chronic HE is far from understood today. We therefore investigated the effects of chronic, body-weight-adjusted (10 mg ╖ kg-1 ╖ day-1), treatment with CIT in rats with and without portacaval shunts (PCS). Open-field activity was monitored. The 5-HT, 5-HIAA, noradrenaline (NA), and dopamine (DA) output were assessed in the frontal neocortex. The racemic levels of CIT and its metabolites DCIT and DDCIT, including the S- and R-enantiomers, were determined in serum, brain parenchyma, and extracellular fluid. The rats with PCS showed higher (2-3-fold) levels of CIT than rats undergoing a sham treatment with CIT in all compartments investigated. The PCS rats also showed elevated levels of DCIT and DDCIT. No major differences in the S/R ratios between PCS rats and control rats could be detected. The CIT treatment resulted in neocortical output differences between PCS rats and control rats mainly within the 5-HT and DA systems but not within the NA system. For the 5-HT system, this change was further evidenced by outspoken elevation in 5-HT output after KCl-depolarizing challenges. Moreover, the CIT treatment to PCS rats was shown to "normalize" the metabolic turnover of 5-HT, measured as a profound lowering of a basal elevation in the 5-HIAA levels. The CIT treatment resulted in an increased or "normalized" behavioral activity in the PCS group. Therefore, a dose-equal chronic treatment with CIT in PCS rats produced pharmacokinetic and pharmacodynamic changes not observed in control rats. The results further support the contention of an altered 5-HT neurotransmission prevailing in the chronic HE condition. However, the tentatively beneficial behavioral response also seen following chronic CIT treatment to PCS rats in this study has to be viewed in relation to both the pharmacokinetic and pharmacodynamic changes observed.

  • 2.
    Boiso, Samuel
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Health Sciences.
    Zackrisson, Anna Lena
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Jakobsen Falk, Ingrid
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Health Sciences.
    Karlsson, Louise
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Health Sciences.
    Carlsson, Björn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Pharmacology.
    Tillmar, Andreas
    Natl Board Forens Med, Dept Forens Genet and Forens Toxicol, Linkoping, Sweden .
    Kugelberg, Fredrik
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Health Sciences.
    Ahlner, Johan
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Health Sciences.
    Hägg, Staffan
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Pharmacology.
    Green, Henrik
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Health Sciences.
    ABCB1 gene polymorphisms are associated with suicide in forensic autopsies2013In: Pharmacogenetics & Genomics, ISSN 1744-6872, E-ISSN 1744-6880, Vol. 23, no 9, p. 463-469Article in journal (Refereed)
    Abstract [en]

    Background Polymorphisms in ABCB1 have the ability to affect both the function and the expression of the transporter protein P-glycoprotein and may lead to an altered response for many drugs including some antidepressants and antipsychotics.Objective The aim of this study was to examine the impact of the ABCB1 polymorphisms 1199Gandgt;A, 1236Candgt;T, 2677Gandgt;T/A, and 3435Candgt;T in deaths by suicide.Patients and methods A total of 998 consecutive Swedish forensic autopsies performed in 2008 in individuals 18 years of age or older, where femoral blood was available and a toxicological screening had been performed, were investigated. Genotypes were assessed with pyrosequencing and information on the cause and manner of each death was obtained from the forensic pathology and toxicology databases.Results There was a significantly higher frequency of the T allele at positions 1236, 2677, and 3435 among the suicide cases compared with the nonsuicide cases.Conclusion Our result from forensic cases suggests that ABCB1 polymorphisms are associated with an increased risk for completed suicides. The biological mechanisms involved and the clinical implications for these findings are largely unknown and need to be examined further.

  • 3.
    Carlsson, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Chiral analsysi of drugs and their metabolites - possibilities and limitations2004In: Chiral forms of drugs from molecule to the clinic, Swedish Society for Pharmacology, Clinical Pharmacology and Therapuetics,2004, 2004Conference paper (Other academic)
  • 4.
    Carlsson, Björn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    From achiral to chiral analysis of citalopram2003Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Within the field of depression the “monoamine hypothesis” has been the leading theory to explain the biological basis of depression. This theory proposes that the biological basis of depression is due to a deficiency in one or more of three key neurotransmitter systems, namely noradrenaline, dopamine and serotonin which are thought to mediate the therapeutic actions of virtually every known antidepressant agent.

    Citalopram is a selective serotonin-reuptake inhibitor (SSRI) used for the treatment of depression and anxiety disorders. Citalopram is a racemic compound, in other words composed of a 50:50 mixture of two enantiomers (S-(+)-citalopram and R-(-)-citalopram) and with one of the enantiomers (S-(+)-citalopram) accounting for the inhibitory effect. At the time of introduction of citalopram the physician needed a therapeutic drug monitoring service to identify patients with interactions, compliance problems and for handling questions concerning polymorphic enzymes and drug metabolism. An achiral analytical separation method based on solid-phase extraction followed by high-performance liquid chromatography (HPLC) was developed for routine therapeutic drug monitoring (TDM) of citalopram and its two main demethylated metabolites.

    As the data available on citalopram were from achiral concentration determinations and to be able to further investigate citalopram enantiomers effects and distribution, a chiral method for separation of the enantiomers of citalopram and its demethylated metabolites was established. The advances within chiral separation techniques have made measurement of the concentrations of the individual enantiomers in biological fluids possible.

    The process behind enantioselective separation is however not fully understood and the mechanism behind the separation can be further scrutinized by the use of multivariate methods. A study of the optimization and characterization of the separation of the enantiomers of citalopram, desmethylcitalopram and didesmethylcitalopram on an acetylated ß-cyclodextrin column, by use of two different chemometric programs - response surface modelling and sequential optimization was performed. Sequential optimization can be a quicker mean of optimizing a chromatographic separation; response surface modelling, in addition to enabling optimization of the chromatographic process, also serves as a tool for learning more about the separation mechanism.

    Studies of the antidepressant effect and pharmacokinetics of citalopram have been performed in adults, but the effects on children and adolescents have only been studied to a minor extent, despite the increasing use of citalopram in these age groups.

    A study was initiated to investigate adolescents treated for depression, with respect to the steady-state plasma concentrations of the enantiomers of citalopram and its demethylated metabolites. The ratios between the S- and R-enantiomers of citalopram and didesmethylcitalopram were in agreement with studies involving older patients. The concentrations of the S-(+)- and R-(-) enantiomers of citalopram and desmethylcitalopram were also in agreement with values from earlier studies. The results indicate that the use of oral contraceptives may have some influence on the metabolism of citalopram. This might be because of an interaction of the contraceptive hormones with the polymorphic CYP2C19 enzyme.

    Even though the SSRIs are considered less toxic compared with older monoamine-active drugs like the tricyclic/tetracyclic antidepressants, the risk of developing serious side effects such as ECG abnormalities and convulsions has been seen for citalopram, when larger doses have been ingested. Furthermore, fatal overdoses have been reported where citalopram alone was the cause of death. Data on the toxicity of each of the enantiomers in humans have not been reported and no data on blood levels of the enantiomers in cases of intoxication have been presented.

    An investigation was initiated on forensic autopsy cases where citalopram had been found at the routine screening and these cases were further analysed with enantioselective analysis to determine the blood concentrations of the enantiomers of citalopram and metabolites. Furthermore the genotyping regarding the polymorphic enzymes CYP2D6 and CYP2C19 were performed.

    In 53 autopsy cases, we found increasing S/R ratios with increasing concentrations of citalopram. We found also that high citalopram S/R ratio were associated with high parent drug to metabolite ratio and may be an indicator of recent intake. Only 3.8 % were found to be poor metabolizers regarding CYP2D6 and for CYP2C19 no poor metabolizer was found.

    Enantioselective analysis of citalopram and its metabolites can provide valuable information about the time that has elapsed between intake and death. Genotyping can be of help in specific cases but the possibility of pharmacokinetic interactions is apparently a far greater problem than genetic enzyme deficiency.

    List of papers
    1. Solid-phase extraction with end-capped C2 columns for the routine measurement of racemic citalopram and metabolites in plasma by high-performance liquid chromatography
    Open this publication in new window or tab >>Solid-phase extraction with end-capped C2 columns for the routine measurement of racemic citalopram and metabolites in plasma by high-performance liquid chromatography
    1997 (English)In: Journal of Chromatography B: Biomedical Sciences and Applications, ISSN 1570-0232, Vol. 702, no 1-2, p. 234-239Article in journal (Refereed) Published
    Abstract [en]

    An assay based on solid-phase extraction followed by high-performance liquid chromatography (HPLC) was developed for the measurement of citalopram and its main metabolites desmethylcitalopram and didesmethylcitalopram. The best extraction procedure was performed with end-capped C2 column utilising secondary silanol interactions to obtain clean extract. The HPLC analysis was done on a phenyl column with a mobile phase without any amine additives. Fluorescence detection gave a limit of detection of 0.8 nmol/l plasma for the compounds analysed.

    Keywords
    Citalopram, Desmethylcitalopram, Didesmethylcitalopram
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-13689 (URN)10.1016/S0378-4347(97)00366-6 (DOI)
    Available from: 2003-06-20 Created: 2003-06-20 Last updated: 2009-08-17
    2. Optimization and Characterization of the Chiral Separation of Citalopram and its Demethylated Metabolites by Response Surface Methodology
    Open this publication in new window or tab >>Optimization and Characterization of the Chiral Separation of Citalopram and its Demethylated Metabolites by Response Surface Methodology
    2001 (English)In: Chromatographia, ISSN 0009-5893, Vol. 53, no 5/6, p. 266-272Article in journal (Refereed) Published
    Abstract [en]

    Response-surface modelling and sequential optimization have been used for optimization and characterization of the separation of the enantiomers of citalopram, desmethylcitalopram, and didesmethylcitalopram on an acetylated ▀-cyclodextrin column. In the model chosen the separation conditions mobile phase methanol content, buffer concentration, column temperature, and pH were varied to investigate their influence on the chromatography. It was found that what is good for selectivity within an enantiomer pair is bad for selectivity between enantiomer pairs. Because within-pair and between-pair selectivity does not reach its optimum at the same conditions, a middle course approach has to be followed. Use of an experimental design for this investigation enabled understanding of the mechanisms of within- and between-pair separation for citalopram, desmethylcitalopram, and didesmethylcitalopram. Sequential optimization can be a quicker means of optimizing a chromatographic separation, response-surface modelling, in addition to enabling optimization of the chromatographic process, also serves as a tool for learning more about the separation mechanism.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-13690 (URN)
    Available from: 2003-06-20 Created: 2003-06-20 Last updated: 2009-08-17
    3. Enantioselective Analysis of Citalopram and Metabolites in Adolescents
    Open this publication in new window or tab >>Enantioselective Analysis of Citalopram and Metabolites in Adolescents
    Show others...
    2001 (English)In: Therapeutic drug monitoring, ISSN 0163-4356, Vol. 23, no 6, p. 658-664Article in journal (Refereed) Published
    Abstract [en]

    Studies of the antidepressant effect and pharmacokinetics of citalopram have been performed in adults, but the effects on children and adolescents have only been studied to a minor extent despite its increasing use in these age groups. The aim of this study was to investigate a group of adolescents treated for depression, with respect to the steady-state plasma concentrations of the enantiomers of citalopram and its demethylated metabolites desmethylcitalopram and didesmethylcitalopram. Moreover, the authors studied the genotypes for the polymorphic cytochrome P450 enzymes CYP2D6 and CYP2C19 in relation to the different enantiomers. The S/R ratios of citalopram and desmethylcitalopram found in this study of 19 adolescents were similar to studies involving older patients. The concentrations of the R-(-)- and S-(+)-enantiomers of citalopram and desmethylcitalopram were also in agreement with values from earlier studies, the R-(-)-enantiomer (distomer) being the major enantiomer. The results indicate that the use of oral contraceptives may have some influence on the metabolism of citalopram. This might be because of an interaction of the contraceptive hormones with the CYP2C19 enzyme.

    Keywords
    Citalopram; Enantiomer; Genotypes; Adolescent
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-13691 (URN)10.1097/00007691-200112000-00011 (DOI)
    Available from: 2003-06-20 Created: 2003-06-20 Last updated: 2013-10-28
    4. Enantioselective analysis of citalopram and its metabolites in postmortem blood and genotyping for CYD2D6 and CYP2C19
    Open this publication in new window or tab >>Enantioselective analysis of citalopram and its metabolites in postmortem blood and genotyping for CYD2D6 and CYP2C19
    Show others...
    2004 (English)In: Journal of Analytical Toxicology, ISSN 0146-4760, E-ISSN 1945-2403, Vol. 28, no 2, p. 94-104Article in journal (Refereed) Published
    Abstract [en]

    Citalopram, a selective serotonin reuptake inhibitor, is one of the most commonly found drugs in Swedish forensic autopsy cases. Citalopram is a racemic drug with 50:50 of the S- and R- enantiomers. Enantioselective analysis of citalopram and its metabolites desmethylcitalopram and didesmethylcitalopram were performed in femoral blood from 53 autopsy cases by a chiral high-performance liquid chromatography (HPLC) method. The mean (± standard deviation) S/R ratio for citalopram was 0.67 ± 0.25 and for desmethylcitalopram, 0.68 ± 0.20. We found increasing S/R ratios with increasing concentrations of citalopram. We also found that high citalopram S/R ratios were associated with a high parent drug-to-metabolite ratio and may be an indicator of recent intake. Citalopram is metabolized by cytochrome P450 (CYP) 3A4, 2C19, and 2D6. Genotyping for the polymorphic CYP2C19 and CYP2D6 revealed no poor metabolizers regarding CYP2C19 and only 2 (3.8%) poor metabolizers regarding CYP2D6. The presence of drugs metabolized by and/or inhibiting these enzymes in several of the cases suggests that such pharmacokinetic interactions are a more important (practical) problem than metabolic deficiency. Enantioselective analysis of citalopram and its metabolites can provide additional information when interpreting forensic toxicology results and might be a necessity in the future.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-13692 (URN)10.1093/jat/28.2.94 (DOI)
    Available from: 2003-06-20 Created: 2003-06-20 Last updated: 2017-12-13
  • 5.
    Carlsson, Björn
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Cherma Yeste, Maria Dolores
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Bengtsson, Finn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Achiral determination of venlafaxine and metabolites, in human plasma, by high-performance liquid chromatography and on-line automated sample preparation using restricted access material.2002In: 18th European Workshop on Drug Metabolism, Valencia, Spain,2002, 2002Conference paper (Refereed)
  • 6.
    Carlsson, Björn
    et al.
    Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Holmgren, A.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Forensic Science and Toxicology .
    Ahlner, Johan
    Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology . Linköping University, Faculty of Health Sciences.
    Bengtsson, Finn
    Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Enantioselective analysis of citalopram and escitalopram in postmortem blood together with genotyping for CYP2D6 and CYP2C192009In: Journal of Analytical Toxicology, ISSN 0146-4760, Vol. 33, no 2, p. 65-76Article in journal (Refereed)
    Abstract [en]

    Citalopram is marketed as a racemate (50:50) mixture of the S(+)-enantiomer and R(-)-enantiomer and the active S(+)-enantiomer (escitalopram) that possess inhibitory effects. Citalopram was introduced in Sweden in 1992 and is the most frequently used antidepressant to date in Sweden. In 2002, escitalopram was introduced onto the Swedish market for treatment of depression and anxiety disorders. The main objective of this study was to investigate S(+)-citalopram [i.e., the racemic drug (citalopram) or the enantiomer (escitalopram)] present in forensic autopsy cases positive for the presence of citalopram in routine screening using a non-enantioselective bioanalytical method. Fifty out of the 270 samples found positive by gas chromatography-nitrogen-phosphorus detection were further analyzed using enantioselective high-performance liquid chromatography. The 50 cases were genotyped for CYP2D6 and CYP2C19, as these isoenzymes are implicated in the metabolism of citalopram and escitalopram. In samples positive for racemic citalopram using the screening method for forensic autopsy cases, up to 20% would have been misinterpreted in the absence of an enantioselective method. An enantioselective method is thus necessary for correct interpretation of autopsy cases, after the enantiomer has been introduced onto the market. The percentage of poor metabolizers was 6% for CYP2D6 and 8% for CYP2C19.

  • 7.
    Carlsson, Björn
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Holmgren, Anita
    RMV.
    Ahlner, Johan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology.
    Bengtsson, Finn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Citalopram and escitalopram in postmortem blood: Confirmation of screening results from autopsy cases with enantioselective analysis.2007In: Nordisk kollokvium Rättstoxikologi.,2007, 2007Conference paper (Other academic)
  • 8.
    Carlsson, Björn
    et al.
    Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Norlander, Björn
    Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology . Linköping University, Faculty of Health Sciences.
    Optimization and Characterization of the Chiral Separation of Citalopram and its Demethylated Metabolites by Response Surface Methodology2001In: Chromatographia, ISSN 0009-5893, Vol. 53, no 5/6, p. 266-272Article in journal (Refereed)
    Abstract [en]

    Response-surface modelling and sequential optimization have been used for optimization and characterization of the separation of the enantiomers of citalopram, desmethylcitalopram, and didesmethylcitalopram on an acetylated ▀-cyclodextrin column. In the model chosen the separation conditions mobile phase methanol content, buffer concentration, column temperature, and pH were varied to investigate their influence on the chromatography. It was found that what is good for selectivity within an enantiomer pair is bad for selectivity between enantiomer pairs. Because within-pair and between-pair selectivity does not reach its optimum at the same conditions, a middle course approach has to be followed. Use of an experimental design for this investigation enabled understanding of the mechanisms of within- and between-pair separation for citalopram, desmethylcitalopram, and didesmethylcitalopram. Sequential optimization can be a quicker means of optimizing a chromatographic separation, response-surface modelling, in addition to enabling optimization of the chromatographic process, also serves as a tool for learning more about the separation mechanism.

  • 9.
    Carlsson, Björn
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Microbiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Norlander, Björn
    Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology . Linköping University, Faculty of Health Sciences.
    Solid-phase extraction with end-capped C2 columns for the routine measurement of racemic citalopram and metabolites in plasma by high-performance liquid chromatography1997In: Journal of Chromatography B: Biomedical Sciences and Applications, ISSN 1570-0232, Vol. 702, no 1-2, p. 234-239Article in journal (Refereed)
    Abstract [en]

    An assay based on solid-phase extraction followed by high-performance liquid chromatography (HPLC) was developed for the measurement of citalopram and its main metabolites desmethylcitalopram and didesmethylcitalopram. The best extraction procedure was performed with end-capped C2 column utilising secondary silanol interactions to obtain clean extract. The HPLC analysis was done on a phenyl column with a mobile phase without any amine additives. Fluorescence detection gave a limit of detection of 0.8 nmol/l plasma for the compounds analysed.

  • 10.
    Carlsson, Björn
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Olsson, Gunilla
    Reis, Margareta
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Psychiatry.
    Wålinder, Jan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Psychiatry. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Psychiatry.
    Nordin, Conny
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Psychiatry. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Psychiatry.
    Lundmark, Jöns
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Psychiatry. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Psychiatry.
    Adolescents on chronic oral dosing with racemic citalopram. Enantioselective analysis of citalopram and CYP2D6/CYP2C19 genotyping. 5 th Congress of the European Association for Clinical Pharmacology and Therapuetics, Odense, Denmark 12-15 september 20012001In: Pharmacology and Toxicology,2001, 2001, p. 132-132Conference paper (Refereed)
  • 11.
    Carlsson, Björn
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Olsson, Gunilla
    Linköping University, Department of Clinical and Experimental Medicine, Oncology. Linköping University, Faculty of Health Sciences.
    Reis, Margareta
    Linköping University, Department of Neuroscience and Locomotion, Psychiatry. Linköping University, Faculty of Health Sciences.
    Wålinder, Jan
    Linköping University, Department of Clinical and Experimental Medicine, Psychiatry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Psychiatry.
    Nordin, Conny
    Linköping University, Department of Clinical and Experimental Medicine, Psychiatry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Psychiatry.
    Lundmark, Jöns
    Linköping University, Department of Clinical and Experimental Medicine, Geriatric. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Geriatric Medicine.
    Scordo, M. G.
    Dahl, M-L.
    Bengtsson, Finn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Ahlner, Johan
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Enantioselective Analysis of Citalopram and Metabolites in Adolescents2001In: Therapeutic drug monitoring, ISSN 0163-4356, Vol. 23, no 6, p. 658-664Article in journal (Refereed)
    Abstract [en]

    Studies of the antidepressant effect and pharmacokinetics of citalopram have been performed in adults, but the effects on children and adolescents have only been studied to a minor extent despite its increasing use in these age groups. The aim of this study was to investigate a group of adolescents treated for depression, with respect to the steady-state plasma concentrations of the enantiomers of citalopram and its demethylated metabolites desmethylcitalopram and didesmethylcitalopram. Moreover, the authors studied the genotypes for the polymorphic cytochrome P450 enzymes CYP2D6 and CYP2C19 in relation to the different enantiomers. The S/R ratios of citalopram and desmethylcitalopram found in this study of 19 adolescents were similar to studies involving older patients. The concentrations of the R-(-)- and S-(+)-enantiomers of citalopram and desmethylcitalopram were also in agreement with values from earlier studies, the R-(-)-enantiomer (distomer) being the major enantiomer. The results indicate that the use of oral contraceptives may have some influence on the metabolism of citalopram. This might be because of an interaction of the contraceptive hormones with the CYP2C19 enzyme.

  • 12.
    Chalise, Jaya Prakash
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences.
    Chenna Narendra, Sudeep
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences.
    Biggs, Sophie
    Region Östergötland, Heart and Medicine Center, Department of Rheumatology.
    Kalinke, Ulrich
    Twincore, Germany.
    Iacono, Alberta
    Department of Experimental Medicine, University of Perugia, Perugia, Italy.
    Boon, Louis
    EPIRUS Biopharmaceuticals, Utrecht, Netherlands.
    Magnusson, Mattias
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences.
    Regulatory T cells manifest IFN-α mediated protection during antigen induced arthritisManuscript (preprint) (Other academic)
    Abstract [en]

    Introduction

    Type I interferon induces tolerance against arthritogenic antigen and protects against antigen induced arthritis (AIA). Regulatory T cells (Treg cells) resolve aberrant immune reaction, maintain self-tolerance and prevent the development of autoimmune diseases. We here investigated the impact of Interferon alpha (IFN-α) on Treg cells development and function during antigen induced arthritis.

    Methods

    For AIA, mice were immunized with methylated bovine serum albumin (mBSA) at day 1 and 7 in presence or absence of IFN-α. At day 21, arthritis was induced by intra-articular injection of mBSA and arthritis was evaluated at day 28. At various days of AIA, CD4, CD25, Foxp3 and CTLA-4 expression was quantified by FACS in blood cells, splenocytes, lymph nodes cells and in ex vivo re-stimulated leucocytes (pooled splenocytes and lymph nodes cells) isolated at same days. To investigate the importance of Treg cells in IFN-α protection in AIA, Foxp3DTReGFP+mice were used, where Treg cells can be depleted transiently by administration of diptherin toxin. CFSE based suppression assay was used to assess the suppression by Treg cells isolated day 4, 10, 20 of AIA against proliferation of mBSA or anti-CD3 stimulated responder T cells (Tresp cells) isolated at same days. For adoptive transfer experiments, 250,000 Treg cells from IFN-α treated or untreated mice day 20 of AIA were intravenously injected to recipient pre-immunized mice without IFN-α treatment during the induction of arthritis. The importance of IFN-α signalling on T cells for the IFN-α protection was evaluated by using CD4-Cre+/- IFNAR flox/flox mice.

    Results

    Protective effects of IFN-α in AIA were associated with significant TGF-β dependent increase in Foxp3+ T cells in blood at day 4 and minor increase of Foxp3+T cells in spleen and lymph node cells. However IFN-α signalling in T cells is not required for IFN-α-protection. Upon ex vivo re-stimulation in presence of IFN-α with mBSA but not anti-CD3, the Treg cells numbers were increased in leucocytes isolated from day 4 and day 10 of AIA. Transient depletion of Treg cells during induction of arthritis (day 21) abolished IFN-α-protection however the protection was not affected when Treg cells are depleted during immunization phase (day 1 and day 7). Against mBSA-stimulated proliferation of Tresp cells, suppression by Treg cells isolated from day 10 and day 20 from IFN-α treated mice are significantly higher than Treg cells from untreated mice. Treg cells isolated from IFN-α or untreated mice at day 20 of AIA when transferred to pre-immunized untreated mice prevent the development of arthritis.

    Conclusion

    Treg cells are critically associated with IFN-α protective effects in AIA. IFN-α enhances TGF-β dependent early development of Treg cells and later IFN-α enhances their suppressive capacity against T cells proliferation in antigen specific manner during AIA.

  • 13.
    Chalise, Jaya Prakash
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences.
    Pallotta, Maria Teresa
    Department of Experimental Medicine, University of Perugia, Perugia, Italy.
    Chenna Narendra, Sudeep
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences.
    Carlsson, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Pharmacology.
    Iacono, Alberta
    Department of Experimental Medicine, University of Perugia, Perugia, Italy.
    Boon, Louis
    EPIRUS Biopharmaceuticals, Utrecht, Netherlands.
    Grohmann, Ursula
    Department of Experimental Medicine, University of Perugia, Perugia, Italy.
    Magnusson, Mattias
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences.
    IDO1 and TGF- 1 β mediate protective effects of IFN-α in antigen-induced arthritisManuscript (preprint) (Other academic)
    Abstract [en]

    Interferon-α (IFN-α) prevents antigen-induced arthritis (AIA) in mice by an unknown mechanism. Indoleamine 2, 3 dioxygenase 1 (IDO1) is an immunoregulator via enzymatic as well as signalling activity, which can be activated by TGF-β and further mediated via non canonical NF-κB signalling. We here investigated whether IDO1 and TGF-β are involved in IFN-α protective effects in AIA. Arthritis was induced in wt, Ido1-/- or Ifnar-/- mice, treated or not with IFN-α or kynurenine, the main IDO1 product, and antibodies neutralizing TGF-β or 1-methyltryptophan (1-MT), an inhibitor of IDO1 catalytic activity. IDO1 expression and enzymatic activity were determined by RT-PCR and HPLC, respectively. Proliferation was measured by 3H-Thymidine incorporation. Non-canonical NF-κB signalling was evaluated by ELISA and Western blot in plasmacytoid DCs (pDCs) from treated mice. Protective effects of IFN-α in AIA were associated with increased IDO1 expression and kynurenine production in spleen cells, particularly at the time of mBSA sensitization. Lack of IDO1 ablated IFN-α protection and kynurenine prevented AIA in an IFNAR-independent manner. The IDO1 catalytic activity was crucial for IFN-α effects at the sensitization but not effector phase of AIA. The disease effector phase in mice treated with IFN-α was instead characterized by sustained IDO1 and TGF-β expression and activation of the noncanonical NF-κB pathway in pDCs. IFN-α protective effects in AIA involves IDO1 enzymatic and signalling activity in the disease sensitization and effector phase, respectively. Kynurenine, the main IDO1 metabolite, can be used as an alternative treatment to IFN-α in protecting mice from AIA.

  • 14.
    Cherma Yeste, Maria Dolores
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology.
    Carlsson, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Bengtsson, Finn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Achiral determination of venlafaxine and metabolities in human plasma by high-performance liquid chromatography and on-line automated sample preparation using restricted access material. Outcome from an naturalistic setting2004In: 8th International Congress of Therapeutic Drug Monitoring and Clinical Toxikology,2004, 2004Conference paper (Other academic)
  • 15.
    Cherma Yeste, Maria Dolores
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Carlsson, Björn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Pharmacology.
    Löfgren, Ulla-Britt
    Östergötlands Läns Landsting.
    Almkvist, Göran
    Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Primary Health Care Centres.
    Hallert, Claes
    Linköping University, Department of Social and Welfare Studies, Health, Activity, Care. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in the East of Östergötland.
    Bengtsson, Finn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Pharmacology.
    Prescription of antidepressant drugs in elderly nursing home patients.: A Follow-up investigation with focus on enantioselective citalopram analysis2007Conference paper (Other academic)
  • 16.
    Haage, Pernilla
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences. National Board of Forensic Medicine, Department of Forensic Genetics and Forensic Toxicology, Linköping Sweden.
    Kronstrand, Robert
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences. National Board of Forensic Medicine, Department of Forensic Genetics and Forensic Toxicology, Linköping Sweden.
    Carlsson, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Region Östergötland, Center for Diagnostics, Department of Clinical Pharmacology. Linköping University, Faculty of Medicine and Health Sciences.
    Josefsson, Martin
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering. National Board of Forensic Medicine, Department of Forensic Genetics and Forensic Toxicology, Linköping Sweden.
    Quantitation of the enantiomers of tramadol and its three main metabolites in human whole blood using LC-MS/MS.2016In: Journal of Pharmaceutical and Biomedical Analysis, ISSN 0731-7085, E-ISSN 1873-264X, Vol. 119, p. 1-9Article in journal (Refereed)
    Abstract [en]

    The analgesic drug tramadol and its metabolites are chiral compounds, with the (+)- and (-)-enantiomers showing different pharmacological and toxicological effects. This novel enantioselective method, based on LC-MS/MS in reversed phase mode, enabled measurement of the parent compound and its three main metabolites O-desmethyltramadol, N-desmethyltramadol and N,O-didesmethyltramadol simultaneously. Whole blood samples of 0.5g were fortified with internal standards (tramadol-(13)C-D3 and O-desmethyl-cis-tramadol-D6) and extracted under basic conditions (pH 11) by liquid-liquid extraction. Chromatography was performed on a chiral alpha-1-acid glycoprotein (AGP) column preceded by an AGP guard column. The mobile phase consisted of 0.8% acetonitrile and 99.2% ammonium acetate (20mM, pH 7.2). A post-column infusion with 0.05% formic acid in acetonitrile was used to enhance sensitivity. Quantitation as well as enantiomeric ratio measurements were covered by quality controls. Validation parameters for all eight enantiomers included selectivity (high), matrix effects (no ion suppression/enhancement), calibration model (linear, weight 1/X(2), in the range of 0.25-250ng/g), limit of quantitation (0.125-0.50ng/g), repeatability (2-6%) and intermediate precision (2-7%), accuracy (83-114%), dilution integrity (98-115%), carry over (not exceeding 0.07%) and stability (stable in blood and extract). The method was applied to blood samples from a healthy volunteer administrated a single 100mg dose and to a case sample concerning an impaired driver, which confirmed its applicability in human pharmacokinetic studies as well as in toxicological and forensic investigations.

  • 17.
    Holmgren, Per
    et al.
    Linköping University, Department of Medical and Health Sciences, Forensic Science and Toxicology . Linköping University, Faculty of Health Sciences.
    Carlsson, Björn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Zackrisson, Anna-Lena
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Lindblom, Bertil
    Linköping University, Department of Clinical and Experimental Medicine, Forensic Genetics. Linköping University, Faculty of Health Sciences.
    Dahl, Marja-Liisa
    Department of Medical Sciences, Clinical Pharmacology, University Hospital, Uppsala, Sweden.
    Scordo, Maria Gabriella
    Department of Medical Laboratory Sciences and Technology, Division of Clinical Pharmacology, Karolinska Institutet, University Hospital, Stockholm, Sweden.
    Druid, Henrik
    National Board of Forensic Medicine and Department of Forensic Medicine, Karolinska Institutet, Solna, Sweden.
    Ahlner, Johan
    Linköping University, Department of Medical and Health Sciences, Forensic Science and Toxicology . Linköping University, Faculty of Health Sciences.
    Enantioselective analysis of citalopram and its metabolites in postmortem blood and genotyping for CYD2D6 and CYP2C192004In: Journal of Analytical Toxicology, ISSN 0146-4760, E-ISSN 1945-2403, Vol. 28, no 2, p. 94-104Article in journal (Refereed)
    Abstract [en]

    Citalopram, a selective serotonin reuptake inhibitor, is one of the most commonly found drugs in Swedish forensic autopsy cases. Citalopram is a racemic drug with 50:50 of the S- and R- enantiomers. Enantioselective analysis of citalopram and its metabolites desmethylcitalopram and didesmethylcitalopram were performed in femoral blood from 53 autopsy cases by a chiral high-performance liquid chromatography (HPLC) method. The mean (± standard deviation) S/R ratio for citalopram was 0.67 ± 0.25 and for desmethylcitalopram, 0.68 ± 0.20. We found increasing S/R ratios with increasing concentrations of citalopram. We also found that high citalopram S/R ratios were associated with a high parent drug-to-metabolite ratio and may be an indicator of recent intake. Citalopram is metabolized by cytochrome P450 (CYP) 3A4, 2C19, and 2D6. Genotyping for the polymorphic CYP2C19 and CYP2D6 revealed no poor metabolizers regarding CYP2C19 and only 2 (3.8%) poor metabolizers regarding CYP2D6. The presence of drugs metabolized by and/or inhibiting these enzymes in several of the cases suggests that such pharmacokinetic interactions are a more important (practical) problem than metabolic deficiency. Enantioselective analysis of citalopram and its metabolites can provide additional information when interpreting forensic toxicology results and might be a necessity in the future.

  • 18.
    Karlsson, Louise
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Carlsson, Björn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Pharmacology.
    Hiemke, Christoph
    Department of Psychiatry and Psychotherapy, University Medical Center of the Johannes Gutenberg-University of Mainz, Mainz, Germany.
    Ahlner, Johan
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Bengtsson, Finn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Pharmacology.
    Schmitt, Ulrich
    Department of Psychiatry and Psychotherapy, University Medical Center of the Johannes Gutenberg-University of Mainz, Mainz, Germany.
    Kugelberg, Fredrik C.
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Altered brain concentrations of citalopram and escitalopram in P-glycoprotein deficient mice after acute and chronic treatment2013In: European Neuropsychopharmacology, ISSN 0924-977X, E-ISSN 1873-7862, Vol. 23, no 11, p. 1636-1644Article in journal (Refereed)
    Abstract [en]

    Background: According to both in vitro and in vivo data P-glycoprotein (P-gp) may restrict the uptake of several antidepressants into the brain, thus contributing to the poor success rate of current antidepressant therapies. The therapeutic activity of citalopram resides in the Senantiomer, whereas the R-enantiomer is practically devoid of serotonin reuptake potency. To date, no in vivo data are available that address whether the enantiomers of citalopram and its metabolites are substrates of P-gp.

    Methods: P-gp knockout (abcb1ab (-/-)) and wild-type (abcb1ab (+/+)) mice underwent acute (single-dose) and chronic (two daily doses for 10 days) treatment with citalopram (10 mg/kg) or escitalopram (5 mg/kg). Serum and brain samples were collected 1-6 h after the first or last i.p. injection for subsequent drug analysis by an enantioselective HPLC method. Results: In brain, 3-fold higher concentrations of S- and R-citalopram, and its metabolites, were found in abcb1ab (-/-) mice than in abcb1ab (+/+) mice after both acute and chronic citalopram treatments. After escitalopram treatment, the S-citalopram brain concentration was 3-5 times higher in the knockout mice than in controls.

    Conclusions: The results provide novel evidence that the enantiomers of citalopram are substrates of P-gp. Possible clinical and toxicological implications of this finding need to be further elucidated.

  • 19.
    Karlsson, Louise
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Green, Henrik
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Zackrisson, Anna Lena
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Bengtsson, Finn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Jakobsen Falk, I
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Carlsson, Björn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Pharmacology.
    Ahlner, Johan
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Kugelberg, Fredrik
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    ABCB1 gene polymorphisms are associated with fatal intoxications involving venlafaxine but not citalopram2013In: International journal of legal medicine (Print), ISSN 0937-9827, E-ISSN 1437-1596, Vol. 127, no 3, p. 579-586Article in journal (Refereed)
    Abstract [en]

    P-glycoprotein (P-gp), encoded by the ABCB1/MDR1 gene, is a drug transporter at the blood–brain barrier. Several polymorphisms in the ABCB1 gene are known to affect the activity and/or expression of P-gp, thereby influencing the treatment response and toxicity of P-gp substrates like citalopram and venlafaxine. In this study, we aimed to investigate the frequency of ABCB1 genotypes in forensic autopsy cases involving these two antidepressants. Further, the distribution of ABCB1 genotypes in deaths related to intoxication was compared to cases not associated to drug intoxication. The study included 228 forensic autopsy cases with different causes and manners of deaths. The ABCB1 single nucleotide polymorphisms (SNPs) G1199A, C1236T, C3435T and G2677T/A for these individuals were determined. The SNPs C1236T and C3435T in venlafaxine-positive cases were significantly different between the intoxication cases and non-intoxications. This was not seen for cases involving citalopram, indicating that the effect of genetic variants might be substrate specific. This novel finding should, however, be confirmed in future studies with larger number of cases.

  • 20.
    Karlsson, Louise
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Green, Henrik
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Zackrisson, Anna Lena
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Bengtsson, Finn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Pharmacology.
    Jakobsen Falk, Ingrid
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Carlsson, Björn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Pharmacology.
    Ahlner, Johan
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Kugelberg, Fredrik C.
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    ABCB1 gene polymorphisms in forensic autopsy cases positive for citalopram and venlafaxineManuscript (preprint) (Other academic)
    Abstract [en]

    P-glycoprotein (P-gp), encoded by the ABCB1/MDR1 gene, is a drug transporter expressed on e.g. the endothelial cells of the blood-brain barrier which regulates the efflux of many drugs. Several polymorphisms in the ABCB1 gene are known to affect the activity and/or expression of P-gp, thereby influencing the treatment response and toxicity of P-gp substrates. It has previously been shown that the antidepressant drugs citalopram and venlafaxine are actively transported out of the brain by P-gp using a mouse model. In the present study we aimed to investigate the frequency of ABCB1 genotypes in forensic autopsy cases positive for these two antidepressants. Further, the distribution of ABCB1 genotypes in deaths related to intoxication was compared to cases not associated to drug intoxication. The present study included 228 forensic autopsy cases positive for venlafaxine and citalopram with different causes of deaths. The ABCB1 single nucleotide polymorphisms (SNPs) G1199A, C1236T, C3435T and G2677T/A for these individuals were determined by Pyrosequencing. The SNPs C1236T, G2677T and C3435T in venlafaxine positive cases were significantly different between the intoxication cases and non-intoxications. The latter novel finding should, however, be confirmed in future studies with larger number of cases.

  • 21.
    Karlsson, Louise
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Hiemke, Christoph
    Department of Psychiatry and Psychotherapy, University Medical Center of the Johannes Gutenberg-University of Mainz, Germany .
    Carlsson, Björn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Pharmacology.
    Josefsson, Martin
    Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine, Artillerigatan 12, Sweden.
    Ahlner, Johan
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Bengtsson, Finn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Pharmacology.
    Schmitt, Ulrich
    Department of Psychiatry and Psychotherapy, University Medical Center of the Johannes Gutenberg-University of Mainz, Germany .
    Kugelberg, Fredrik C
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Effects on enantiomeric drug disposition and open-field behavior after chronic treatment with venlafaxine in the P-glycoprotein knockout mice model2011In: Psychopharmacology, ISSN 0033-3158, E-ISSN 1432-2072, Vol. 215, no 2, p. 367-377Article in journal (Refereed)
    Abstract [en]

    Our results show that P-gp at the blood-brain barrier plays an important role in limiting brain entry of the enantiomers of venlafaxine and its metabolites after chronic dosing. Taken together, the present pharmacokinetic and pharmacodynamic findings offer the possibility that the expression of P-gp in patients may be a contributing factor for limited treatment response.

  • 22.
    Karlsson, Louise
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Kingbäck, Maria
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Josefsson, M
    Rättsmedicinalverket, Rättskemi.
    Carlsson, Björn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Pharmacology.
    Ahlner, Johan
    Linköping University, Department of Medical and Health Sciences, Forensic Science and Toxicology . Linköping University, Faculty of Health Sciences.
    Schmidt, U
    Tyskland.
    Kugelberg, Fredrik
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Hiemke, Ch
    Tyskland.
    Bengtsson, Finn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Pharmacology.
    Penetration of the enantiomers of venlafaxine and its metabolites into the brain in mice lacking P-glycoprotein (mdr1ab)2008Conference paper (Other academic)
  • 23.
    Karlsson, Louise
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Schmitt, Ulrich
    Department of Psychiatry and Psychotherapy, University Medical Center of the Johannes Gutenberg-University of Mainz, Mainz, Germany.
    Josefsson, Martin
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Carlsson, Björn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Ahlner, Johan
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Bengtsson, Finn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Kugelberg, Fredrik C
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Hiemke, Christoph
    Department of Psychiatry and Psychotherapy, University Medical Center of the Johannes Gutenberg-University of Mainz, Mainz, Germany.
    Blood-brain barrier penetration of the enantiomers of venlafaxine and its metabolites in mice lacking P-glycoprotein2010In: European Neuropsychopharmacology, ISSN 0924-977X, E-ISSN 1873-7862, Vol. 20, no 9, p. 632-640Article in journal (Refereed)
    Abstract [en]

    According to in vitro studies the enantiomers of venlafaxine display different degrees of serotonin and noradrenaline reuptake inhibition. Therefore, clarification of the enantiomeric drug distribution between serum and brain is highly warranted. To elucidate if P-glycoprotein (P-gp) in a stereoselective manner transports venlafaxine and its metabolites out of the brain we used abcb1ab double-knockout mice that do not express P-gp. A single dose of racemic venlafaxine (10 mg/kg bw) was intraperitoneally injected to knockout (-/-) and wildtype (+/+) mice. Serum and brain samples were collected 1, 3, 6 and 9 h following drug administration for analysis by LC/MS/MS. One to six hours post-dose, the brain concentrations of venlafaxine, O-desmethylvenlafaxine and N-desmethylvenlafaxine were 2-3, 2-6 and 3-12 times higher in abcb1ab (-/-) mice compared to abcb1ab (+/+) mice, respectively. No major differences in the serum and brain disposition of the S- and R-enantiomers of venlafaxine and its metabolites were found between the groups. We conclude that P-gp decreases the penetration of the S- and R-enantiomers of venlafaxine and its major metabolites into the brain. No evidence of a stereoselective P-gp mediated transport of these substances was observed.

  • 24.
    Karlsson, Louise
    et al.
    Region Östergötland, Center for Diagnostics, Department of Clinical Pharmacology. Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences.
    Zackrisson, Anna Lena
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences. Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine, Linköping, Sweden.
    Josefsson, M
    Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine, Linköping, Sweden; 3Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden.
    Carlsson, Björn
    Region Östergötland, Center for Diagnostics, Department of Clinical Pharmacology. Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Green, Henrik
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences. Department of Forensic Genetics andForensic Toxicology, National Board of Forensic Medicine, Linköping, Sweden.
    Kugelberg, Fredrik C
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences. Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine, Linköping, Sweden.
    Influence of CYP2D6 and CYP2C19 genotypes on venlafaxine metabolic ratios and stereoselective metabolism in forensic autopsy cases.2015In: The Pharmacogenomics Journal, ISSN 1470-269X, E-ISSN 1473-1150, Vol. 15, no 2, p. 165-71Article in journal (Refereed)
    Abstract [en]

    We investigated whether polymorphisms in the CYP2D6 and CYP2C19 genes influence the metabolic ratios and enantiomeric S/R ratios of venlafaxine (VEN) and its metabolites O-desmethylvenlafaxine (ODV), N-desmethylvenlafaxine (NDV) and N,O-didesmethylvenlafaxine (DDV) in blood from forensic autopsy cases. In all, 94 postmortem cases found positive for VEN during toxicological screening were included. The CYP2D6 genotype was shown to significantly influence the ODV/VEN (P=0.003), DDV/NDV (P=0.010) and DDV/ODV (P=0.034) ratios. The DDV/ODV (P=0.013) and DDV/VEN (P=0.021) ratios were significantly influenced by the CYP2C19 genotype. The S/R ratios of VEN were significantly influenced by both CYP2D6 and CYP2C19 genotypes. CYP2D6 poor metabolizers (PMs) had lower S/R VEN ratios and CYP2C19 PMs had high S/R ratios of VEN in comparison. Our results show that the CYP2D6 genotype influences the O-demethylation whereas CYP2C19 influences the N-demethylation of VEN and its metabolites. In addition, we show a stereoselective metabolism where CYP2D6 favours the R-enantiomer whereas CYP2C19 favours the S-enantiomer.

  • 25.
    Kechagias, Stergios
    et al.
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences.
    Jönsson, K. Å.
    Linköping University, Department of Medicine and Care, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Norlander, Björn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Carlsson, Björn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Jones, A. Wayne
    Linköping University, Department of Medical and Health Sciences, Forensic Science and Toxicology . Linköping University, Faculty of Health Sciences.
    Low-dose aspirin decreases blood alcohol concentrations by delaying gastric emptying1997In: European Journal of Clinical Pharmacology, ISSN 0031-6970, E-ISSN 1432-1041, Vol. 53, no 04-Mar, p. 241-246Article in journal (Refereed)
    Abstract [en]

    Objective: To determine if treatment with low-dose aspirin (ASA) influences the bioavailability of orally administered alcohol and to assess whether this is caused by altered gastric emptying as measured by the paracetamol absorption test.

    Methods: In a single-center controlled crossover trial, ten healthy male medical students, aged 20–27 years, participated in two experiments in random order. Both times they took paracetamol (1.5 g together with a standardized breakfast) and drank ethanol (0.3 g/kg) 1 h after eating breakfast. On one drinking occasion, no previous medication was given. The other alcohol session was performed after the subjects had taken 75 mg ASA once daily for 7 days. On both occasions, venous blood samples were obtained at exactly timed intervals for a period of 3.5 h.

    Results: The blood-ethanol profiles showed large interindividual variations for both experiments. After treatment with ASA, the maximum blood-ethanol concentration was distinctly lower in seven subjects, almost unchanged in two subjects and increased in one subject. Overall, a statistically significant decrease in the peak blood-ethanol concentration was observed. The time required to reach peak blood-ethanol levels was somewhat longer after treatment with ASA. Although the areas under the concentration–time profiles were smaller after ASA treatment, these differences were not statistically significant. The concentrations of paracetamol in plasma were lower when ethanol was ingested after treatment with ASA and the areas under the concentration–time curves (0–170 min) were smaller.

    Conclusions: Intake of low-dose ASA (75 mg daily) tends to delay the absorption of a moderate dose of ethanol, which results in lower peak blood-ethanol concentrations and smaller areas under the concentration–time curves. The underlying mechanism seems to be delayed gastric emptying as indicated by the paracetamol absorption test.

  • 26.
    Kingbäck, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Carlsson, Björn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Ahlner, Johan
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Bengtsson, Finn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Kugelberg, Fredrik
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Cytochrome P450-Dependent Disposition of the Enantiomers of Citalopram and Its Metabolites: In Vivo Studies in Sprague-Dawley and Dark Agouti Rats2011In: Chirality, ISSN 0899-0042, E-ISSN 1520-636X, Vol. 23, no 2, p. 172-177Article in journal (Refereed)
    Abstract [en]

    The female Sprague-Dawley (SD) and Dark Agouti (DA) rats are considered the animal counterparts of the human extensive and poor metabolizer cytochrome P450 (CYP) 2D6 phenotypes, respectively. The aim of this work was to study possible rat strain differences in the steady-state pharmacokinetics of the (+)-(S)- and (-)-(R)-enantiomers of citalopram and its demethylated metabolites. A chronic drug treatment regimen (15 mg/kg daily) was implemented for 13 days in separate groups of SD (n 5 9) and DA (n 5 9) rats by using osmotic pumps. The concentrations of citalopram and two major metabolites in serum and two brain regions were analyzed by an enantioselective high-performance liquid chromatography assay. Higher serum and brain levels of citalopram and demethylcitalopram, but lower levels of didemethylcitalopram, were observed in DA rats when compared with SD rats. The enantiomeric (S/R) concentrations ratios of citalopram were lower in the DA rats when compared with the SD rats (0.53 +/- 0.05 vs. 0.80 +/- 0.03, P andlt; 0.001), indicating a possibly decreased capacity in the metabolism of the (-)-(R)-enantiomer in the DA rats. This study shows that CYP2D deficiency results in steady-state pharmacokinetic differences of the enantiomers of citalopram and its metabolites.

  • 27.
    Kingbäck, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Josefsson, M
    Linköping University, Department of Medical and Health Sciences, Pharmacology.
    Kugelberg, Fredrik
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Bengtsson, Finn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Pharmacology.
    Ahlner, Johan
    Linköping University, Department of Medical and Health Sciences, Forensic Science and Toxicology . Linköping University, Faculty of Health Sciences.
    Carlsson, Björn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Pharmacology.
    Stereoselective analysis of venlafaxine and its three major metabolites by liquid chromatography with electrospray tandem mass spectrometry2008Conference paper (Other academic)
  • 28.
    Kingbäck, Maria
    et al.
    Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology . Linköping University, Faculty of Health Sciences.
    Josefsson, Martin
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Karlsson, Louise
    Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology . Linköping University, Faculty of Health Sciences.
    Ahlner, Johan
    Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology . Linköping University, Faculty of Health Sciences.
    Bengtsson, Finn
    Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Kugelberg, Fredrik C
    Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology . Linköping University, Faculty of Health Sciences.
    Carlsson, Björn
    Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Stereoselective determination of venlafaxine and its three demethylated metabolites in human plasma and whole blood by liquid chromatography with electrospray tandem mass spectrometric detection and solid phase extraction2010In: Journal of Pharmaceutical and Biomedical Analysis, ISSN 0731-7085, E-ISSN 1873-264X, Vol. 53, no 3, p. 583-590Article in journal (Refereed)
    Abstract [en]

    A stereoselective method is described for simultaneous determination of the S- and R-enantiomers of venlafaxine and its three demethylated metabolites in human plasma and whole blood samples. This validated method involved LC/MS/MS with positive electrospray ionization and solid phase extraction. Chromatographic separation was performed on a 250 mm x 2.1mm Chirobiotic V column with a total run time of 35 min. In plasma, calibration curves were in the range of 1-1000 nM for the S- and R-enantiomers of venlafaxine and O-desmethylvenlafaxine, and 0.5-500 nM for N-desmethylvenlafaxine and N,O-didesmethylvenlafaxine. In whole blood the corresponding concentrations were 10-4000 and 5-2000 nM, respectively. The intra-day precision was <6.3% and the inter-day precision was <9.9% for plasma and <15% and <19% for whole blood. LLOQ ranged between 0.25 and 0.5 nM. No ion suppression/enhancement or other matrix effects were observed. The method was successfully applied for determination of venlafaxine and its metabolites in plasma from patients and whole blood samples from forensic autopsy cases.

  • 29.
    Kingbäck, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Karlsson, Louise
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Carlsson, Björn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Josefsson, Martin
    Department of Forensic Genetics and Forensic Toxicology,National Board of Forensic Medicine.
    Ahlner, Johan
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Bengtsson, Finn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Kugelberg, Fredrik
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Pharmacokinetic Differences in the Disposition of the Enantiomers of Venlafaxine and Its Metabolites in Sprague-Dawley and Dark Agouti RatsManuscript (preprint) (Other academic)
    Abstract [en]

    Venlafaxine is a frequently prescribed racemic antidepressant drug worldwide, consisting of two enantiomers that exhibit similar but not identical biological activity profiles. Venlafaxine is extensively metabolised by the cytochrome P450 (CYP) system. CYP2D6 is involved in the formation of O-desmethylvenlafaxine (Odm-venlafaxine) and CYP3A4 in the formation of Ndesmethylvenlafaxine (Ndm-venlafaxine). The female Dark Agouti and Sprague-Dawley rats are considered the animal counterparts of the human CYP2D6 poor and extensive metaboliser phenotypes, respectively. Since CYP2D6 seems to play a major role in the metabolism of venlafaxine, the aim of this work was to study possible differences in the pharmacokinetics of the enantiomers of venlafaxine and its metabolites in these two different rat strains. Following single administration of racemic venlafaxine (15 mg/kg) serum and brain samples were collected and the concentrations of the enantiomers of venlafaxine and its three major metabolites were determined using an enantioselective LC/MS/MS method. Higher serum and brain concentrations of venlafaxine were observed in Dark Agouti rats as compared to Sprague-Dawley rats (p=0.0002). In relation to the Odm-venlafaxine concentration, the Ndmvenlafaxine concentrations were much higher in Dark Agouti rats than in Sprague-Dawley rats (p<0.0001). The enantiomeric (S/R) venlafaxine ratios were almost two times higher in Dark Agouti rats than in Sprague-Dawley rats, which was observed in both serum and brain (p<0.0001). The present results give hints for possible differences in the pharmacokinetics of venlafaxine in human extensive and poor metaboliser CYP2D6 phenotype subjects.

  • 30.
    Kingbäck, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Karlsson, Louise
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Zackrisson, Anna-Lena
    National Board of Forensic Medicine, Linköping, Sweden.
    Josefsson, Martin
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Health Sciences. National Board of Forensic Medicine, Linköping, Sweden.
    Carlsson, Björn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Pharmacology.
    Bengtsson, Finn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Pharmacology.
    Ahlner, Johan
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Kugelberg, Fredrik C
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Influence of CYP2D6 genotype on the disposition of the enantiomers of venlafaxine and its major metabolites in postmortem femoral blood2012In: Forensic Science International, ISSN 0379-0738, E-ISSN 1872-6283, Vol. 214, no 1-3, p. 124-134Article in journal (Refereed)
    Abstract [en]

    Venlafaxine (VEN) is an antidepressant drug mainly metabolized by the cytochrome P450 (CYP) enzyme CYP2D6 to the active metabolite O-desmethylvenlafaxine (ODV). VEN is also metabolized to N-desmetylvenlafaxine (NDV) via CYP3A4. ODV and NDV are further metabolized to N,O-didesmethylvenlafaxine (DDV). VEN is a racemic mixture of the S- and R-enantiomers and these have in vitro displayed different degrees of serotonin and noradrenaline reuptake inhibition. The aim of the study was to investigate if an enantioselective analysis of VEN and its metabolites, in combination with genotyping for CYP2D6, could assist in the interpretation of forensic toxicological results in cases with different causes of deaths. Concentrations of the enantiomers of VEN and metabolites were determined in femoral blood obtained from 56 autopsy cases with different causes of death. The drug analysis was done by liquid chromatography tandem mass spectrometry (LC/MS/MS) and the CYP2D6 genotyping by PCR and pyrosequencing. The mean (median) enantiomeric S/R ratios of VEN, ODV, NDV and DDV were 0.99 (0.91), 2.17 (0.93), 0.92 (0.86) and 1.08 (1.03), respectively. However, a substantial variation in the relationship between the S- and R-enantiomers of VEN and metabolites was evident (S/R ratios ranging from 0.23 to 17.6). In six cases, a low S/R VEN ratio (mean 0.5) was associated with a high S/R ODV ratio (mean 11.9). Genotyping showed that these individuals carried two inactive CYP2D6 genes indicating a poor metabolizer phenotype. From these data we conclude that enantioselective analysis of VEN and ODV can predict if a person is a poor metabolizer genotype/phenotype for CYP2D6. Knowledge of the relationship between the S- and R-enantiomers of this antidepressant drug and its active metabolite is also important since the enantiomers display different pharmacodynamic profiles.

  • 31.
    Kugelberg, Fredrik
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology.
    Alkass, Kanar
    Kingbäck, Maria
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology.
    Carlsson, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Influence of blood loss on the pharmacokinetics of citalopram2006In: Forensic Science International, ISSN 0379-0738, E-ISSN 1872-6283, Vol. 161, no 2-3, p. 163-168Article in journal (Refereed)
    Abstract [en]

    Extended blood loss results in several compensatory physiological mechanisms, including transfer of extravascular fluid into the blood circulation. If drugs are present in the body, this fluid exchange may imply that blood drug concentrations found in a trauma victim may differ from the concentrations present at the time of the trauma. To address this issue, an animal model was used to investigate the influence of blood loss on pre-existing levels of the antidepressant drug citalopram and its demethylated metabolites. Rats were administered citalopram either acutely (40 mg/kg, orally) or chronically (20 mg/kg daily, subcutaneously) for 6 days using osmotic pumps. In the experimental rats, blood loss was accomplished by withdrawing 0.8 mL blood at 10 min intervals during 70 min. In the control rats, blood was withdrawn at 0 and 70 min only. Blood, brain and lung drug concentrations were analyzed with an enantioselective HPLC method. In the chronically treated rats, the ratios between final and initial citalopram concentrations were 1.08 ± 0.15 and 1.01 ± 0.09 in the experimental rats and controls, respectively, indicating no major effect of blood loss. In contrast, acute oral administration resulted in increased ratios in the exsanguinated rats as compared to controls (1.84 ± 0.50 versus 0.73 ± 0.07, p = 0.0495). In conclusion, the observation of increased blood drug levels in the acute oral rats indicates that absorption of fluid from the gastrointestinal tract may be important in the intravascular refill. Further, in the interpretation of post-mortem blood levels of drugs, these physiological mechanisms should be taken into account. © 2006 Elsevier Ireland Ltd. All rights reserved.

  • 32.
    Kugelberg, Fredrik
    et al.
    Linköping University, Department of Medicine and Care, Clinical Pharmacology. Linköping University, Department of Neuroscience and Locomotion, Psychiatry.
    Apelqvist, Gustav
    Department of Clinical Pharmacology, Institute of Laboratory Medicine, Lund University, Lund, Sweden.
    Carlsson, Björn
    Linköping University, Department of Medicine and Care, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Ahlner, Johan
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Bengtsson, Finn
    Linköping University, Department of Medicine and Care, Clinical Pharmacology. Linköping University, Department of Neuroscience and Locomotion, Psychiatry. Linköping University, Faculty of Health Sciences.
    In vivo steady-state pharmacokinetic outcome following clinical and toxic doses of racemic citalopram to rats2001In: British Journal of Pharmacology, ISSN 0007-1188, E-ISSN 1476-5381, Vol. 132, no 8, p. 1683-1690Article in journal (Refereed)
    Abstract [en]
    • The thymoleptic drug citalopram (CIT) belongs to the selective serotonin reuptake inhibitors (SSRIs) and is today extensively used in psychiatry. Further clarification of the enantiomer-selective distribution of racemic CIT in both clinical and toxic doses is highly warranted.

    • By a steady-state in vivo paradigm, rats underwent chronic systemic exposure for 10 days by using osmotic pumps and the total as well as the individual distributions of the S- and R-enantiomers of CIT, and its metabolites in serum and two different brain regions, were analysed.

    • In serum, the S/R ratios in the groups treated with 10, 20, or 100 mg kg−1 day−1 were 0.94, 0.83, and 0.34, respectively. The ratios were almost the same in the brain regions.

    • In the group treated with 100 mg kg−1 day−1, the serum and brain total CIT levels were found to be 20 times and 6 – 8 times higher than in the rats treated with 10 or 20 mg kg−1 day−1, respectively. In all groups, the CIT levels were higher in brain tissue as compared to serum.

    • In a spontaneous open-field behavioural test, a correlation between clinical and toxic drug concentrations was observed.

    • In conclusion, the R-enantiomer was present in an increased proportion compared with the S-enantiomer when higher steady-state CIT concentration was prevailing. This is of particular interest, since the S-enantiomer is responsible for the inhibition of serotonin reuptake in vitro. The present data may be of importance, as full understanding on where different racemic or enantiomeric drug effects of CIT and its main metabolites are unravelled.

  • 33.
    Kugelberg, Fredrik
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology.
    Apelqvist, Gustav
    Carlsson, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Ahlner, Johan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology.
    Bengtsson, Finn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Sustained citalopram treatment in experimental hepatic encephalopathy: Effects on entrainment to the light-dark cycle and melatonin2006In: Basic & Clinical Pharmacology & Toxicology, ISSN 1742-7835, E-ISSN 1742-7843, Vol. 99, no 1, p. 80-88Article in journal (Refereed)
    Abstract [en]

    Patients with chronic hepatic encephalopathy often display altered diurnal rhythm as well as other affective disturbances which motivate treatment with antidepressants. We investigated the effects of sustained treatment with citalopram (10 mg/kg daily, 10 days) on 24-hr behavioural open-field activities in portacaval-shunted (PCS) rats and sham-operated control rats. In addition, the daytime and nighttime serum melatonin levels, as well as the serum concentrations of the enantiomers of citalopram and its metabolites, were analyzed. Untreated PCS rats showed reduced locomotor and rearing activities during nighttime. Citalopram treatment resulted in elevated behavioural activity in the PCS rats during night, indicative of an improved entrainment to the light-dark cycle, whereas no behavioural effect could be observed in sham rats. Higher melatonin levels in both PCS and sham rats were observed during nighttime compared with daytime, but the untreated PCS rats also showed higher daytime melatonin level than the corresponding sham group. Citalopram treatment seemed not to have any major effect on the melatonin levels. Higher serum levels of both citalopram and metabolites were observed in PCS rats as compared to sham rats. An altered ratio between the S- and R-enantiomers could also be observed in the PCS rats. In conclusion, the present data support the contention of a disturbed diurnal rhythm, and that the melatonin activity may be altered, in chronic hepatic encephalopathy. The citalopram treatment resulted in similar behavioural performances and daytime serum melatonin levels in PCS rats and controls, although pharmacokinetic differences were present between the groups. © Basic & Clinical Pharmacology & Toxicology 2006, All rights reserved.

  • 34.
    Kugelberg, Fredrik
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology.
    Carlsson, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology.
    Ahlner, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology.
    Bengtsson, Finn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology.
    Pharmacokinetics of citalopram enantiomers after chronic and acute administration of racemate in rats.2002In: Nord J Psychiatry,2002, 2002, p. 22-22Conference paper (Refereed)
  • 35.
    Kugelberg, Fredrik
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology.
    Carlsson, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Ahlner, Johan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology.
    Bengtsson, Finn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Disposition of the enantiomers of citalipram and its demethylated metabolites in rats.2003In: Ther Drug Monit,2003, 2003, p. 527-527Conference paper (Refereed)
  • 36.
    Kugelberg, Fredrik
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology .
    Carlsson, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology . Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology .
    Ahlner, Johan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology .
    Bengtsson, Finn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology . Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology .
    Disposition of the enantiomers of citalopram and its demethylated metabolites in rats2003In: Therapeutic Drug Monitoring, ISSN 0163-4356, E-ISSN 1536-3694, Vol. 25, no 4, p. 163-Conference paper (Other academic)
  • 37.
    Kugelberg, Fredrik
    et al.
    Linköping University, Department of Medicine and Care, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Carlsson, Björn
    Linköping University, Department of Medicine and Care, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Ahlner, Johan
    Linköping University, Department of Medicine and Care, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Bengtsson, Finn
    Linköping University, Department of Medicine and Care, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Stereoselective single-dose kinetics of citalopram and its metabolites in rats2003In: Chirality, ISSN 0899-0042, E-ISSN 1520-636X, Vol. 15, no 7, p. 622-629Article in journal (Refereed)
    Abstract [en]

    The single-dose kinetics of the enantiomers of citalopram (CIT) and its metabolites, demethylcitalopram (DCIT) and didemethylcitalopram (DDCIT), were investigated after administration of 10, 20, or 100 mg/kg (s.c.) rac-CIT to rats. Samples from serum and two brain regions were collected 1, 3, 10, or 20 h postdose for HPLC analysis. In the 100 mg/kg rats, the enantiomeric (S/R) serum concentration ratios of CIT decreased during the study period (0.93 at 1 h vs. 0.59 at 20 h; P < 0.001). In the 10 and 20 mg/kg rats, the decrease in serum S/R CIT ratios was not so evident as in the 100 mg/kg rats. In all three groups the S/R CIT ratio was almost the same in the brain as in serum, although both CIT enantiomer levels in the brain were found to be 5–10 times higher than the levels in serum. The serum and brain metabolite levels were low in the 10 and 20 mg/kg rats, whereas the levels increased during the study period in the 100 mg/kg rats. In conclusion, the CIT enantiomers were shown for the first time to be stereoselectively metabolized after single-dose administration to rats, as previously shown in steady-state dosing studies in humans and rats. Chirality 15:622–629, 2003. © 2003 Wiley-Liss, Inc.

  • 38.
    Kugelberg, Fredrik
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology.
    Carlsson, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Ahlner, Johan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology.
    Bengtsson, Finn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Ther Drug Monit: Disposition of the enantiomers of citalopram and its demethlated metabolites in rats.2003In: Skriv in din egen text för ej reg. tidskrift etc.,2003, 2003, p. 527-527Conference paper (Refereed)
  • 39.
    Kugelberg, Fredrik
    et al.
    Linköping University, Department of Medicine and Care, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Druid, Henrik
    Division of Forensic Medicine, Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden.
    Carlsson, Björn
    Linköping University, Department of Medicine and Care, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Ahlner, Johan
    Linköping University, Department of Medicine and Care, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Bengtsson, Finn
    Linköping University, Department of Medicine and Care, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Postmortem redistribution of the enantiomers of citalopram and its metabolites: an experimental study in rats2004In: Journal of Analytical Toxicology, ISSN 0146-4760, E-ISSN 1945-2403, Vol. 28, no 8, p. 631-637Article in journal (Refereed)
    Abstract [en]

    A rat model was used to study if postmortem redistribution of the S- and R-enantiomers of citalopram (CIT) and its metabolites demethylcitalopram (DCIT) and didemethylcitalopram (DDCIT) occurs after three different subcutaneous dosing procedures with racemic CIT. Two groups underwent chronic administration (20 mg/kg daily) using osmotic pumps. After 10 days, 1 of these groups received an acute-on-chronic drug challenge with a single injection of 100 mg/kg. The third group received the single 100 mg/kg dose only. Heart blood and brain samples were collected antemortem and 1, 3, or 24 h postmortem for enantioselective HPLC analysis. Increased postmortem blood drug and metabolite concentrations compared with corresponding antemortem concentrations were observed in all groups (p < 0.05 to p < 0.001). At 24 h after death, the ratios between postmortem and antemortem blood concentrations were around 3–4 for CIT as well as for the metabolites. In the brain, no major differences between antemortem and postmortem drug and metabolite concentrations were observed. The enantiomeric (S/R) concentrations ratios of CIT and metabolites in blood and brain were of similar magnitude before and after death. No differences between antemortem and postmortem parent drug-to-metabolite (P/M) ratios for CIT/DCIT in blood were observed. Finally, this animal model demonstrates that the S- and R-enantiomers of CIT and its metabolites were redistributed to the same extent postmortem.

  • 40.
    Kugelberg, Fredrik
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology.
    Kingbäck, Maria
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology.
    Carlsson, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Druid, H
    Rättsmedicin KI.
    Early-phase postmortem redistribution of the enantiomers of citalopram and its demethylated metabolites in rats2005In: Journal of Analytical Toxicology, ISSN 0146-4760, E-ISSN 1945-2403, Vol. 29, no 4, p. 223-228Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to investigate the early-phase postmortem redistribution of the enantiomers of citalopram (CIT) and its metabolites demethylcitalopram (DCIT) and didemethylcitalopram (DDCIT) in a rat model. Furthermore, we wanted to examine the role of the lungs as a reservoir of postmortem drug release and to investigate the influence of storage temperature (21°C vs. 4°C) on postmortem changes. Rats were administered a single CIT dose of 100 mg/kg (s.c.), and heart blood and lung samples were collected antemortem and 15 min postmortem for enantioselective high-performance liquid chromatographic analysis. About three times higher blood drug and metabolite levels were observed in the postmortem rats than in the antemortem rats (p < 0.0001). Refrigeration at 4°C did not prevent, but significantly reduced, the postmortem increase in heart blood CIT levels as compared to the concentrations in the rats stored at 21°C (p < 0.05). The lung drug concentrations were lower postmortem than antemortem (p < 0.05). The enantiomeric (S/R) concentration ratios of CIT and metabolites in blood and lungs were of similar magnitude before and after death. The parent-drug-to- metabolite ratios for CIT/DCIT were unchanged after death. In conclusion, this study shows that heart blood CIT and metabolite levels increase rapidly after death. Further, a fall in postmortem CIT concentrations in the lungs was observed, indicating that the lungs seemed to represent one major source of drug release during early-phase postmortem redistribution.

  • 41.
    Kugelberg, Fredrik
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology.
    Kingbäck, Maria
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology.
    Carlsson, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Druid, H
    Rättsmedicin KI.
    Postmortem redistribution of the enantiomers of citalopram and its metabolites in a rat model2005In: Joint SOFT/TIAFT/FBI meeting on Forensic Toxicology,2005, Niles, Illinois, USA: Preston publications , 2005, p. 494-Conference paper (Refereed)
  • 42.
    Kugelberg, Fredrik
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology.
    Kingbäck, Maria
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology.
    Carlsson, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Druid, Henrik
    Postmortem redistribution of the enantiomers of citalopram and itsmetabolities in a rat model2004In: 2004 SOFT/TIAFT meeting,2004, 2004, p. 338-338Conference paper (Other academic)
  • 43.
    Reis, Margareta
    et al.
    Linköping University, Department of Medicine and Care, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Cherma Yeste, Maria Dolores
    Linköping University, Department of Medicine and Care, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Carlsson, Björn
    Linköping University, Department of Medicine and Care, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Bengtsson, Finn
    Linköping University, Department of Medicine and Care, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Therapeutic Drug Monitoring of Escitalopram in an outpatient setting2007In: Therapeutic Drug Monitoring, ISSN 0163-4356, E-ISSN 1536-3694, Vol. 29, no 6, p. 758-766Article in journal (Refereed)
    Abstract [en]

    The main objectives of this study were to outline the inter- and intraindividual and overall pharmacokinetic variability of S-citalopram, S-desmethylcitalopram, and S-didesmethylcitalopram in serum by means of therapeutic drug monitoring, and to investigate potential correlations between the serum concentration and simultaneously collected clinical data. The study was conducted on outpatients in Sweden in 2002 to 2005. Included in the pharmacokinetic evaluation were 155 patients (68% women and 32% men) aged 17 to 95 years (average, 51 years). One serum sample per patient, taken as a trough value in steady state, was assessed. For the inter- and intraindividual variation calculation, 16 patients were included with two eligible samples each. The median daily dose was 20 mg/day (range, 5-40 mg). Extensive overall serum concentration variability was seen for all dose levels. The interindividual coefficient of variation for dose-normalized concentrations was 71% for S-citalopram, 36% for S-desmethylcitalopram, and 50% for S- didesmethylcitalopram. The intraindividual variations over time for the same parameters were approximately 30%, except for the ratio S-desmethylcitalopram/S- citalopram, which was 23%. The median S-desmethylcitalopram level was approximately 60% of the parent substance and the S-didesmethylcitalopram level approximately 9%. Higher age was correlated with higher serum concentrations, but no gender-related concentration differences were found. A majority (76%) of the patients took one or more drugs in addition to escitalopram, but concomitant medication did not seem to interact with escitalopram. However, women taking oral contraceptives showed a lower metabolic ratio compared with age-matched women. As a result of the wide range of the ratio in this population, these findings are not considered of clinical relevance.

  • 44.
    Reis, Margareta
    et al.
    Linköping University, Department of Medicine and Care, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Kugelberg, Fredrik
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology.
    Carlsson, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Josefsson, Martin
    Wahldeck, Bertil
    Stereokemi och läkemedelseffekter -ett försummat kunskapsområde2006In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 103, p. 1305-1311Article in journal (Other academic)
    Abstract [sv]

       

  • 45.
    Reis, Margareta
    et al.
    Linköping University, Department of Neuroscience and Locomotion, Psychiatry. Linköping University, Faculty of Health Sciences.
    Olsson, Gunilla
    Division of Child and Adolescence Psychiatry, Department of Neuroscience, Uppsala University, Uppsala.
    Carlsson, Björn
    Linköping University, Department of Medicine and Care, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Lundmark, Jöns
    Linköping University, Department of Neuroscience and Locomotion, Psychiatry. Linköping University, Faculty of Health Sciences.
    Dahl, Marja-Liisa
    Clinical Pharmacology, Department of Medical Sciences, Uppsala University, Uppsala.
    Wålinder, Jan
    Linköping University, Department of Neuroscience and Locomotion, Psychiatry. Linköping University, Faculty of Health Sciences.
    Ahlner, Johan
    Linköping University, Department of Medicine and Care, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Bengtsson, Finn
    Linköping University, Department of Neuroscience and Locomotion, Psychiatry. Linköping University, Department of Medicine and Care, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Serum levels of citalopram and its main metabolites in adolescent patients treated in a naturalistic clinical setting2002In: Journal of Clinical Psychopharmacology, ISSN 0271-0749, E-ISSN 1533-712X, Vol. 22, no 4, p. 406-413Article in journal (Refereed)
    Abstract [en]

    The prescribing of selective serotonin reuptake inhibitors for adolescents is extensive despite the fact that there are few pharmacokinetic (PK), effi]cacy, safety, or tolerability studies on this group. This study reports the PK findings from two trials in adolescents treated with citalopram (CIT) in naturalistic clinical settings: one retrospective and one prospective. The aim of our study was to describe serum concentrations of CIT, desmethylcitalopram (DCIT), and didesmethylcitalopram (DDCIT) (trough values in steady state) in adolescents in relation to daily dose and clinical information obtained from therapeutic drug monitoring request forms. Altogether, 44 patients younger than 21 years were scrutinized using this combined open-label approach. The main findings were that (1) there was a pronounced interindividual variability of serum CIT, DCIT, and DDCIT concentrations in all doses prescribed, in agreement with previous studies on adults; on correcting for dose, the coefficient of variance was about 50% for CIT, DCIT, and DDCIT; (2) the transformation of CIT to DCIT and of DCIT to DDCIT was similar within the dose range 20 to 60 mg/day; (3) there was a difference between the sexes on comparing the dose-corrected concentrations of CIT and DCIT, with girls presenting significantly higher values than boys; and (4) there was a strong dose-serum concentration relationship in three identified subgroups of adolescents: (a) nonsmokers (CIT, r 2 = 0.71; DCIT, r 2 = 0.81), (b) girls not taking oral contraceptives (CIT, r 2 = 0.75; DCIT, r 2 = 0.71,), and (c) girls in the last 14 days of the menstrual cycle (CIT, r 2 = 0.68; DCIT, r 2 = 0.64). In summary, the present study tentatively supports influences of sex, oral contraceptives, and smoking habits on the disposition of CIT in younger patients. Hence, future studies on CIT should assess these parameters.

  • 46.
    Skoglund, Karin
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Health Sciences.
    Boiso, Samuel
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Health Sciences.
    Jönsson, Jan-Ingvar
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Vikingsson, Svante
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Health Sciences.
    Carlsson, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Pharmacology.
    Green, Henrik
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Health Sciences.
    Single-nucleotide polymorphisms of ABCG2 increase the efficacy of tyrosine kinase inhibitors in the K562 chronic myeloid leukemia cell line2014In: Pharmacogenetics & Genomics, ISSN 1744-6872, E-ISSN 1744-6880, Vol. 24, no 1, p. 52-61Article in journal (Refereed)
    Abstract [en]

    ObjectiveThe tyrosine kinase inhibitors (TKIs) used in the treatment of chronic myeloid leukemia are substrates for the efflux transport protein ATP-binding cassette subfamily G member 2 (ABCG2). Variations in ABCG2 activity might influence pharmacokinetics and therapeutic outcome of TKIs. The role of ABCG2 single-nucleotide polymorphisms (SNPs) in TKI treatment is not clear and functional in-vitro studies are lacking. The aim of this study was to investigate the consequences of ABCG2 SNPs for transport and efficacy of TKIs [imatinib, N-desmethyl imatinib (CGP74588), dasatinib, nilotinib, and bosutinib].Materials and methodsABCG2 SNPs 34Ggreater thanA, 421Cgreater thanA, 623Tgreater thanC, 886Ggreater thanC, 1574Tgreater thanG, and 1582Ggreater thanA were constructed from ABCG2 wild-type cDNA and transduced to K562 cells by retroviral gene transfer. Variant ABCG2 expression in cell membranes was evaluated and the effects of ABCG2 SNPs on transport and efficacy of TKIs were measured as the ability of ABCG2 variants to protect against TKI cytotoxicity.ResultsWild-type ABCG2 had a protective effect against the cytotoxicity of all investigated compounds except bosutinib. It was found that ABCG2 expression provided better protection against CGP74588 than its parent compound, imatinib. ABCG2 421Cgreater thanA, 623Tgreater thanC, 886Ggreater thanC, and 1574Tgreater thanG reduced cell membrane expression of ABCG2 and the protective effect of ABCG2 against imatinib, CGP74588, dasatinib, and nilotinib cytotoxicity.ConclusionThese findings show that the ABCG2 SNPs 421Cgreater thanA, 623Tgreater thanC, 886Ggreater thanC, and 1574Tgreater thanG increase the efficacy of investigated TKIs, indicating a reduced transport function that might influence TKI pharmacokinetics in vivo. Furthermore, the active imatinib metabolite CGP74588 is influenced by ABCG2 expression to a greater extent than the parent compound.

  • 47.
    Skoglund, Karin
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Health Sciences.
    Moreno, Samuel Boiso
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Jönsson, Jan-Ingvar
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Vikingsson, Svante
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Health Sciences.
    Carlsson, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Pharmacology.
    Gréen, Henrik
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Health Sciences.
    Influence of variant ABCG2 on tyrosine kinase inhibitor transport and efficacy in the K562 chronic myeloid leukemia cell lineManuscript (preprint) (Other academic)
    Abstract [en]

    Objective: The tyrosine kinase inhibitors (TKIs) used in the treatment of chronic myeloid leukemia are substrates for the efflux transport protein ABCG2. Variations in ABCG2 activity might influence pharmacokinetics and therapeutic outcome of TKIs. The role of ABCG2 single nucleotide polymorphisms (SNPs) in TKI treatment is not clear and functional in vitro studies are lacking. The aim of this study was to investigate the consequences of ABCG2 SNPs for transport and efficacy of TKIs (imatinib, N-desmethyl imatinib (CGP74588), dasatinib, nilotinib and bosutinib). Methods: ABCG2 SNPs 34G>A, 421C>A, 623T>C, 886G>C, 1574T>G and 1582G>A were constructed from ABCG2 wild type cDNA and transduced to K562 cells by retroviral gene transfer. The ability of variant cells to express ABCG2 in the cell membrane and protect against TKI cytotoxicity was investigated. Results: Wild type ABCG2 had a protective effect against the cytotoxicity of all investigated compounds except bosutinib. It was found that ABCG2 expression provided a better protection against CGP74588 than its parent compound, imatinib. ABCG2 421C>A, 623T>C, 886G>C and 1574T>G reduced cell membrane expression of ABCG2 and the protective effect of ABCG2 against imatinib, CGP74588, dasatinib and nilotinib cytotoxicity. The most prominent effect was found for the 623T>C SNP which resulted in undetectable ABCG2 expression and low protection against TKI cytotoxicity. Conclusion: These findings show that the ABCG2 SNPs 421C>A, 623T>C, 886G>C and 1574T>G impair ABCG2 transport function and might influence TKI pharmacokinetics in vivo. Furthermore, the active imatinib metabolite CGP74588 is to a greater extent than the parent compound transported by ABCG2.

  • 48.
    Vikingsson, Svante
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Almer, Sven
    Linköping University, Department of Clinical and Experimental Medicine, Gastroenterology and Hepatology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Gastroentorology.
    Peterson, Curt
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Oncology.
    Carlsson, Björn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Pharmacology.
    Josefsson, Martin
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Monitoring of thiopurine metabolites - A high-performance liquid chromatography method for clinical use2013In: Journal of Pharmaceutical and Biomedical Analysis, ISSN 0731-7085, E-ISSN 1873-264X, Vol. 75, p. 145-152Article in journal (Refereed)
    Abstract [en]

    A high-performance liquid chromatography method capable of measuring thiopurine mono-, di-, and triphosphates separately in red blood cells (RBCs) was developed. RBCs were isolated from whole blood using centrifugation. Proteins were precipitated using dichloromethane and methanol. The thioguanine nucleotides (TGNs) were derivatised using potassium permanganate before analysis. Analytes were separated by ion-pairing liquid chromatography using tetrabutylammonium ions and detected using UV absorption and fluorescence. The method was designed for use in clinical trials. Ten patient samples were analysed to demonstrate clinical application and to establish pilot ranges for all analytes. less thanbrgreater than less thanbrgreater thanThe method measured thioguanosine mono-(TGMP), di-(TGDP), and triphosphate (TGTP), as well as methylthioinosine mono- (meTIMP), di- (meTIDP) and triphosphate (meTITP) in RBCs collected from patients treated with thiopurine drugs (azathioprine, 6-mercaptopurine, and 6-thioguanine). less thanbrgreater than less thanbrgreater thanLOQ was 0.3, 3, 2, 30, 30 and 40 pmol/8 x 10(8) RBC, for TGMP, TGDP, TGTP, meTIMP, meTIDP and meTITP, respectively. Between-day precision were below 14% for all analytes at all concentrations and samples were stable at 4 degrees C for 8 h after sampling.

  • 49.
    Vikingsson, Svante
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Almer, Sven
    Linköping University, Department of Clinical and Experimental Medicine, Gastroenterology and Hepatology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Endocrinology and Gastroenterology UHL.
    Peterson, Curt
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Oncology UHL.
    Carlsson, Björn
    Linköping University, Department of Medical and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Pharmacology.
    Josefsson, Martin
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Monitoring of thiopurine metabolites: A high-performance liquid chromatography method for clinical useManuscript (preprint) (Other academic)
    Abstract [en]

    high-performance liquid chromatography method capable of measuring thiopurine mono-, di-, and triphosphates separately in red blood cells (RBCs) was developed. RBC:s were isolated from whole blood using centrifugation. Proteins were precipitated using dichloromethane and methanol. The thioguanine nucleotides (TGNs) were derivatised using potassium permanganate before analysis. Analytes were separated by ion-pairing liquid chromatography using tetrabutylammonium ions and detected using UV absorption and fluorescence. The method was designed for use in clinical trials in thiopurine therapy and proven valid by analysis of authentic patient samples.

    The method measured thioguanosine mono- (TGMP), di- (TGDP), and triphosphate (TGTP), as well as methylthioinosine mono- (meTIMP), di- (meTIDP) and triphosphate (meTITP) in RBCs collected from patients treated with thiopurine drugs (azathioprine, 6-mercaptopurine, and 6-thioguanine).

    LOQ was 0.3, 3, 2, 30, 30 and 40 pmol/8x10^8 RBC, for TGMP, TGDP, TGTP, meTIMP, meTIDP and meTITP, respectively. Between-day precision were below 14% for all analytes at all concentrations and samples were stable at 5 °C for 8 hours after sampling.

  • 50.
    Vikingsson, Svante
    et al.
    Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Carlsson, Björn
    Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences.
    Almer, Sven H C
    Linköping University, Department of Clinical and Experimental Medicine, Gastroenterology and Hepatology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Department of Endocrinology and Gastroenterology UHL.
    Peterson, Curt
    Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Oncology UHL.
    Monitoring of thiopurine metabolites in patients with inflammatory bowel disease-what is actually measured?2009In: Therapeutic Drug Monitoring, ISSN 0163-4356, E-ISSN 1536-3694, Vol. 31, no 3, p. 345-50Article in journal (Refereed)
    Abstract [en]

    Azathioprine and 6-mercaptopurine are often used in the treatment of patients with inflammatory bowel disease (IBD). They are prodrugs and undergo a complex metabolism to active and inactive metabolites. Thiopurine treatment is monitored in many laboratories by measuring metabolite concentrations in erythrocytes (red blood cells). The metabolites of interest are not measured directly but as hydrolysis products, which can be produced from several metabolites. The aim of this study was to examine which metabolites are actually measured during routine monitoring. Samples from 18 patients treated with a thiopurine were analyzed by a typical routine high-performance liquid chromatography method for therapeutic drug monitoring and by a newly developed specific method measuring thioguanosine monophosphate (TGMP), thioguanosine diphosphate (TGDP), and thioguanosine triphosphate (TGTP), as well as methylthioinosine monophosphate (meTIMP), and the results were compared. 6-Thioguanine nucleotide (TGN) values detected by the routine method were 69% (range 40%-90%) of the sum of TGMP, TGDP, and TGTP measured by the specific method. TGTP and TGDP contributed 85% (range 78%-90%) and 14% (range 10%-21%) of the TGN total, respectively. Thioguanosine was not found in any patient sample. The concentration of meTIMP obtained by the routine method was 548% of the value obtained by the specific method (range 340%-718%). The difference in TGN measurements between the routine and specific methods can be explained by low hydrolysis efficiency in the routine method, although the most likely explanation for the difference in meTIMP values is that not yet identified metabolites are codetermined in the routine high-performance liquid chromatography method. Concentrations reported as TGN during therapeutic drug monitoring of thiopurine metabolites consist of TGDP and TGTP with a minor contribution of the TGMP. Concentrations reported as meTIMP or methyl mercaptopurine consist in part of meTIMP, but other not yet identified metabolites are codetermined.

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