ABSTRACT
Background: Shivering is one of the most common unpleasant complications in the postoperative period. Many clinical trials have been published and revealed various efficacious drugs for the treatment of postanesthetic shivering. Objective: To perform an updated quantitative review of randomized controlled trials (RCTs) studying efficacy of pharmacological treatment of post-anesthetic shivering. Methods: We initiated a systematic search for original articles of randomized, controlled studies of drugs for postanesthetic shivering. Reports were appraised, and binary data of shivering within 15 minutes after treatment were extracted. Relative risk (RR) and the number-needed-to-treat (NNT) were subsequently analyzed and then reported with 95% confidence interval (CI). Results: The efficacy of anti-shivering drugs was analyzed by using data from 32 RCTs. Meperidine 25 to 50 mg, tramadol 0.5 to 1 mg/kg, clonidine 30 to 150 μg, ketanserin 10 mg, doxapram 25 to 100 mg, and nalbuphine 0.05 to 0.1 mg/kg, reported in at least two trials, were significantly more effective than placebo within 15 minutes after treatment. The NNT of meperidine 25 to 50 mg was 1.39, of tramadol 0.5 to 1 mg/kg was 1.56, of ketanserin 10 mg was 2.44, of doxapram 25 to 100 mg was 1.82, and of nalbuphine 0.05 to 0.1 mg/kg was 1.75. The efficacy of tramadol 0.5 to 1 mg/kg was not significantly different from meperidine 0.5 mg/kg (25 mg) at 15 minutes of observation (p = 0.34). Moreover, clonidine 30 to 150 μg was more effective in treating tremor than placebo, with the NNT of 1.43. Studies in efficacy of alfentanil, magnesium sulfate, fentanyl, ondansetron, nefopam, pentazocine, urapidil, morphine, lignocaine, metamizol, and butorphanol, were inadequate for quantitative analysis. Conclusion: Meperidine 25 to 50 mg, tramadol 0.5 to 1 mg/kg, clonidine 30 to 150 μg, doxapram 25 to 100 mg, ketanserin 10 mg, and nalbuphine 0.05 to 0.1 mg/kg can effectively treat postanesthestic shivering within 15 minutes. Tramadol 0.5 to 1 mg was found to a be good alternative compared to meperidine 25 to 50 mg. Side effects of treatments were mild and treatable.