Background: Enhancement of local anaesthetic-produced regional blocks by clonidine seems well established. There are insufficient data about dose-effect relationship of combinations of clonidine with individual agents, efficiency of local versus systemic administration of clonidine, and comparative evaluation of clonidine with vasoconstrictors. Because of unavailability of long-acting local anaesthetics at the time of study, our aim was to evaluate augmentation of lidocaine spinal block with local or systemic clonidine and to compare the results with the efficacy of intrathecal phenylephrine.

Methods: Ninety pts of age 50–72 yrs with ASA 1–4 physical status, scheduled for open prostatectomies, hysterectomies or ostheosynthesis of fractured hip were randomized to one of 6 treatment groups, 15 pts in each. Patients received intrathecally (L₃–L₄) either 100 mg of plain lidocaine (group L100); or a mixture of lidocaine 40 and 80 mg with clonidine 100 μg (groups L40-C100 and L80-C100); or a combination of lidocaine 40 and 80 mg with clonidine 300 μg orally 60 min before spinal puncture (L40-C300 and L80-C300). Addition of intrathecal phenylephrine 5 mg to 80 mg of lidocaine was also investigated (L80-P5).

Results: There were no significant intergroup differences concerning demographic data or type of surgery. All operations (duration up to 150 min) were completed without need for analgesic supplementation. The addition of clonidine resulted in a significant reduction of the onset time of spinal block and prolongation of the duration of sensory and motor blocks compared to plain lidocaine or lidocaine with phenylephrine. In spite of the well-known hypotensive action of α₂-agonists, haemodynamic depression only in group L80-C300 was significantly more pronounced than in L100 and L80-P5 groups. The least decrease of BP and minimal need of rescue ephedrine among all patients studied were recorded in the group receiving low dosage of lidocaine with intrathecal clonidine (L40-C100). Sedation occurred in most patients receiving clonidine.

Conclusion: Our results indicate that addition of clonidine to lidocaine, irrespective of the route of administration, prolongs the duration of spinal block and permits a reduction of the lidocaine dose needed for a given duration of block. Addition of phenylephrine results in a less pronounced statistically significant prolongation of anaesthesia. The regression of sensory block before restoration of motor function seems to be a specific (and unfortunate) effect of both clonidine and phenylephrine.

Background: The purpose of the present study was to evaluate the postoperative analgesic and adverse effects of equal doses of oral or intrathecal clonidine in spinal anaesthesia with bupivacaine plain.

Methods: Forty-five ASA I-III orthopaedic patients scheduled for osteosynthesis of a traumatic femur fracture were randomised in a double-blind fashion to one of 3 groups. Patients received 15 mg of plain bupivacaine intrathecally (group B) or an intrathecal mixture of bupivacaine 15 mg and clonidine 150 mg (group CIT). In group CPO oral clonidine 150 mg was administered 60 min before intrathecal injection of bupivacaine 15 mg.

Results: Oral and intrathecal clonidine prolonged the time until the first request for analgesics, 313 ± 29 and 337 ± 29 min, respectively, vs. 236 ± 27 min in group B (P < 0.01). The total 24- h PCA morphine dose was significantly lower in group CIT(19.3 ± 1.3 mg) compared to groups B and CPO(33.4 ± 2.0 and 31.2 ± 3.1 mg). MAP was decreased significantly during the first hour after intrathecal clonidine(14%) and during the first 5 h after oral clonidine(14–19%). HR decreased in CIT during the 5th and 6th postoperative hours(7–9%) and during the first 2 h(9%) in CPO (P < 0.01). The degree of sedation was more pronounced in group CPO during the first 3 h. Four patients had pruritus in group B.

Conclusions: Addition of intrathecal clonidine prolonged analgesia and decreased morphine consumption postoperatively more than oral clonidine. Hypotension was more pronounced after oral than after intrathecal clonidine. Intrathecal clonidine is therefore recommended.

In this study, we evaluated the effect of intrathecal and oral clonidine as supplements to spinal anesthesia with lidocaine in patients at risk of postoperative alcohol withdrawal syndrome (AWS). We hypothesized that clonidine would have a prophylactic effect on postoperative AWS. Forty-five alcohol-dependent patients (daily ethanol intake >60 g) scheduled for transurethral resection of the prostate were double-blindly randomized into three groups. All patients received hyperbaric lidocaine 100 mg intrathecally. The diazepam group (DiazG) was premedicated with diazepam 10 mg orally; the intrathecal clonidine group (Clon^i/tG) received a placebo (saline) tablet and clonidine 150 μg intrathecally; and the oral clonidine group (Clon^p/oG) received clonidine 150 μg orally. For patients diagnosed with AWS, the Clinical Institute Withdrawal Assessment for Alcohol, revised scale, was used. Twelve patients in the DiazG had symptoms of AWS, compared with two in the Clon^i/tG and one in the Clon^p/oG. The median Clinical Institute Withdrawal Assessment for Alcohol, revised scale, score was 12 in the DiazG versus 1 in the clonidine-treated groups. Two patients in the DiazG had severe delirium. Patients receiving oral clonidine had a slightly decreased mean arterial blood pressure 6–12 h after spinal anesthesia (P < 0.05); patients in the DiazG had a hyperdynamic circulatory reaction 24–72 h after surgery. In conclusion, preoperative clonidine 150 μg, intrathecally or orally, prevented significant postoperative AWS in ethanol-dependent patients.

The aim of this randomized double-blinded study was to see whether the addition of small-dose clonidine to small-dose bupivacaine for spinal anesthesia prolonged the duration of postoperative analgesia and also provided a sufficient block duration that would be adequate for inguinal herniorrhaphy. We randomized 45 patients to 3 groups receiving intrathecal hyperbaric bupivacaine 6 mg combined with saline (Group B), clonidine 15 μg (Group BC15), or clonidine 30 μg (Group BC30); all solutions were diluted with saline to 3 mL. The sensory block level was insufficient for surgery in five patients in Group B, and these patients were given general anesthesia. Patients in Groups BC15 and BC30 had a significantly higher spread of analgesia (two to four dermatomes) than those in Group B. Two-segment regression, return of S1 sensation, and regression of motor block were significantly longer in Group BC30 than in Group B. The addition of clonidine 15 and 30 μg to bupivacaine prolonged time to first analgesic request and decreased postoperative pain with minimal risk of hypotension. We conclude that clonidine 15 μg with bupivacaine 6 mg produced an effective spinal anesthesia and recommend this dose for inguinal herniorrhaphy, because it did not prolong the motor block.

Background:  The perioperative effects of intrathecal and epidural clonidine combined with local anesthetic were evaluated in 60 patients undergoing hip arthroplasty.

Methods:  This was a double-blinded study and the patients were randomized into three groups, with 20 patients in each group. All patients received spinal anesthesia with 17.5 mg of plain bupivacaine with 15 µg of clonidine (Group BC-RC) or without clonidine (Groups B-R and B-RC). Postoperatively, epidural infusion was administered in the following way: Group B-R – ropivacaine 4 mg h⁻¹; Groups B-RC and BC-RC: ropivacaine 4 mg h⁻¹ and clonidine 40 µg h⁻¹. Sensory block was assessed with light touch, pinprick, transcutaneous electrical stimulation at T12 and L2 dermatomes, and perception of thermal stimuli.

Results:  The maximal upper level of sensory block measured by pin-prick (T6–T7) did not differ between the groups while the partial sensory block for cold and warmth were increased two dermatomes above pin-prick level in the group with intrathecal clonidine compared to the other two groups (P < 0.05). Duration of anesthesia, analgesia and motor block were longer in Group BC-RC compared to Groups B-R and B-RC (P < 0.02). Postoperatively, both VAS score on movement and PCA-morphine consumption were higher in Group B-R than in Groups B-RC and BC-RC (P < 0.01). The arterial pressure and heart rate in Groups B-RC and BC-RC were significantly lower than in Group B-R at 10–24 and 15–24 h, respectively, after spinal injection.

Conclusion:  Low-dose intrathecal clonidine provided a better quality of anesthesia and longer-lasting analgesia. Epidural clonidine-ropivacaine infusion resulted in improved postoperative analgesia but was associated with a moderate decrease in blood pressure.