Do anticholinergic agents affect the occurrence of postanaesthetic nausea?

In order to establish if anticholinergic drugs might influence postoperative nausea and vomiting, 100 ASA I-II adult patients scheduled for minor orthopaedic procedures, varicose vein stripping or inguinal herniorraphy were randomised to receive, in a double-blind fashion, either a premedicant and a reversal dose of 0.003 and 0.0075 mg/kg of glycopyrrolate or 0.006 and 0.015 mg/kg of atropine, respectively. Nitrous oxide, after thiopentone induction was used for anaesthesia with fentanyl and diazepam as supplements and pancuronium for relaxation. In the recovery room, up to 2 h after surgery, 28% of the patients in the glycopyrrolate group and 8% in the atropine group experienced nausea (P = 0.017). Thereafter, the patients complained of nausea at decreased and equal frequencies in both groups. The incidence of vomiting was not statistically significantly different. Droperidol was needed, to control persistent emesis, three times more often in the glycopyrrolate than in the atropine group. It is concluded that substitution of glycopyrrolate for atropine increases the likelihood of postoperative nausea, and continued use of atropine should be considered in patients at risk of postoperative emesis.