Control of shivering with clonidine, butorphanol, and tramadol under spinal anesthesia: a comparative study

INTRODUCTION: The present study was designed to evaluate the efficacy of clonidine, butorphanol, and tramadol in control of shivering under spinal anesthesia, and to compare their side effects. METHODS: This randomized, prospective study was conducted in 90 patients who developed shivering under spinal anesthesia during various abdominal or orthopedic surgery procedures. On shivering, patients were randomly allocated to receive an intravenous, 1 mL bolus dose of 50 mg tramadol, or 1 mg butorphanol, or 150 μg clonidine, in a double blinded manner. Control of shivering, time taken for cessation, recurrence, hemodynamic changes, axillary temperatures, and side effects were noted and compared for all 3 groups. Collected data were analyzed using appropriate statistical tests. RESULTS: Butorphanol and tramadol were more effective than clonidine in suppressing shivering. Butorphanol, tramadol, and clonidine completely controlled rigors in 83%, 73%, and 53% of cases, respectively, and incompletely suppressed rigors in 16%, 26%, and 46% of cases, respectively. Time taken to terminate rigors was significantly higher for clonidine (3.3 ± 0.9 minutes) than for butorphanol and tramadol (2.1 ± 1.0 minutes and 1.8 ± 0.5 minutes; P < 0.001). CONCLUSION: Butorphanol had an edge over tramadol in controlling shivering with lower chances of recurrence, though both were superior to clonidine for this purpose with an early onset of action. We conclude that both these opioids control rigors better than α-2 agonists.