A randomized, double‐blind, placebo‐controlled trial comparing pethidine to metamizol for treatment of post‐anaesthetic shivering

1Shivering is frequent during the post‐anaesthetic recovery period, and there is no clear consensus about the best strategy for its treatment. We tested the efficacy of two commonly used analgesic drugs, pethidine and metamizol. 2A randomized, double‐blind, placebo‐controlled clinical trial was performed, including 104 adult patients who presented with post‐anaesthetic shivering during the recovery from general anaesthesia. They were randomized to receive placebo (n=32), metamizol 25 mg kg−1 (n=37), or pethidine 0.4 mg kg−1 (n=35). The response to treatment was assessed 5, 15 and 45 min after drug administration, and the main outcome variable was complete suppression of shivering. 3The efficacy at 5, 15 and 45 min was as follows: placebo 6%, 16% and 37%; metamizol 13.5%, 32% and 76%, and pethidine 89%, 91% and 89%. With both active drugs the efficacy at all three time intervals was significantly higher than that with placebo (P