Dimenhydrinate is an inexpensive antiemetic with few side effects available as an oral, long-acting (LA) formulation (Gravol L/A) containing 25 mg of immediate and 50 mg of sustained release drug. We designed this double-blind comparison trial to assess the efficacy of dimenhydrinate LA versus droperidol alone and the combination for prophylaxis of nausea, vomiting, and retching in outpatient gynecologic laparoscopy. One-hundred-forty-one women were randomized into 3 groups: 1) droperidol (placebo capsule preoperatively and IV droperidol 0.625 mg before induction), 2) dimenhydrinate LA preoperatively and IV placebo before induction, or 3) combination. Information regarding nausea, vomiting, retching, pain, and sedation was recorded in the postanesthesia care unit (PACU) and collected by telephone for the presence of symptoms: on arrival home; at bedtime; upon arising, and at lunchtime the following day. The overall incidence of complete treatment failure (rescue medication in PACU or nausea, vomiting, or retching at any time point) was 28 of 46 (61%), 28 of 48 (58%), and 22 of 47 (47%); and for treatment failure vomiting (rescue medication in PACU or vomiting or retching at any time point) was 16 of 46 (35%), 11 of 48 (23%), and 5 of 47 (11%), for the droperidol, dimenhydrinate, and combination groups, respectively (P = 0.007 for droperidol versus combination). There were no differences in sedation or pain. Preoperative administration of an oral dose of LA dimenhydrinate in combination with droperidol when compared with droperidol alone effectively reduced the incidence of vomiting but not nausea in women undergoing elective outpatient gynecologic laparoscopy.
Implications: Dimenhydrinate is an inexpensive antiemetic with few side effects available as a long-acting oral formulation. Women undergoing outpatient gynecologic laparoscopy were given droperidol, an effective antiemetic, dimenhydrinate alone, or the combination of the two drugs. Dimenhydrinate plus droperidol significantly reduced the overall incidence of vomiting, but not nausea, when compared with droperidol alone.