Double–blind comparison of transdermal scopolamine, droperidol and placebo against postoperative nausea and vomiting

Abstract

Since transdermal scopolamine (TS) seems effective against seasickness, we compared its antiemetic effect with intravenous droperidol (DHBP), our routine antidote for postoperative emesis. Ninety-six female patients (ASA I-II) scheduled for short-stay surgery were randomly allocated to three study groups after giving their informed consent. The three groups were as follows: TS adhesive, delivering 140 .mu.g initially and 5 .mu.g/h thereafter + placebo 0.5 ml i.v. 5 min before the end of surgery; transdermal placebo adhesive preoperatively + DHBP 0.5 ml (1.25 mg) i.v. 5 min before the end of surgery; transdermal placebo + 0.5 ml placebo i.v. as indicated above. Oxycodone i.m. and glycopyrrolate i.v. were given for premedication together with the test adhesive. Anesthesia was induced with thiopental and maintained with nitrous oxide and oxygen, enflurane, vecuronium and fentanyl. Neostigmine and glycopyrrolate were administered for reversal. In the recovery room no differences in nausea or vomiting were observed between the groups. Sedation was significantly more marked (P < 0.15-0.0001) after DHBP than after either TS or the placebo. An additional 1.25 mg DHBP was required in 28% of the patients given TS compared with 13% of those given DHBP and 6% of those given the placebo (P < 0.05). During the following 24 h nausea was reported more by the placebo patients (25) than by those on TS (20) or DHBP (15) (P < 0.05). However, actual vomiting on the ward did not differ between the groups. Visual disturbances were more frequent after TS (P < 0.01). We conclude that prophylactic transdermal scopolamine does not diminish postoperative emetic sequelae.