Nefopam and clonidine in the prevention of postanaesthetic shivering

Postanaesthetic shivering affects up to 70% of patients after general anaesthesia, and may be very distressing. Various drugs have been used to treat or prevent postanaesthetic shivering, but the ideal one has not yet been found. Sixty patients undergoing elective abdominal or orthopaedic surgery under general anaesthesia were included in a randomised, double-blind study. Patients received clonidine (3 microgram.kg-1), nefopam (0.15 mg.kg-1) or saline 0.9% as a placebo at the end of surgery, prior to extubation. Nefopam and clonidine significantly reduced the incidence and severity of shivering in comparison with the placebo. The recovery time, between the end of anaesthesia and extubation, was significantly longer in the clonidine-treated patients [13.6 (5.2) min] than in either the nefopam [9.6 (2.8) min] or the placebo [10.0 (5.4) min] groups. Mean arterial blood pressure and heart rate were significantly lower in the clonidine group compared with both other groups. Our results suggest that nefopam and clonidine are effective in the prevention of postanaesthetic shivering. However, following clonidine administration the recovery time was prolonged and hypotension was significantly greater than after nefopam.