Perspectives on transdermal scopolamine for the treatment of postoperative nausea and vomiting.

Transdermal scopolamine, a patch system that delivers 1.5 mg of scopolamine gradually over 72 hours following an initial bolus, was approved in the United States in 2001 for the prevention of postoperative nausea and vomiting (PONV) in adults. Scopolamine (hyoscine) is a selective competitive anatagonist of muscarinic cholinergic receptors. Low serum concentrations of scopolamine produce an antiemetic effect. Transdermal scopolamine is effective in preventing PONV versus placebo [relative risk (RR)=0.77, 95% confidence interval (CI), 0.61-0.98, P = 0.03] and a significantly reduced risk for postoperative nausea (RR=0.59, 95% CI, 0.48-0.73, P < 0.001), postoperative vomiting (RR=0.68, 95% CI, 0.61-0.76, P < 0.001), and PONV (RR 0.73, 95% CI, 0.60-0.88, P = 001) in the first 24 hours after the start of anesthesia.