Antiemetic efficacy of low-dose midazolam in patients undergoing thyroidectomy

Postoperative nausea and vomiting are distressing and frequent adverse events of anesthesia and surgery, with a high incidence following thyroidectomy. The aim of this study was to evaluate the efficacy of low-dose midazolam for preventing postoperative nausea and vomiting in patients undergoing thyroidectomy.

Prospective, randomized, double-blind, placebo-controlled study.

University-affiliated hospital.

Ninety patients, 30 men and 60 nonpregnant women, received intravenously placebo or midazolam at 2 different doses (50 and 75 µg/kg; n = 30 of each) immediately after induction of anesthesia. A standard general anesthetic technique, including sevoflurane and air in oxygen, was used. Postoperatively, during the first 24 hours after anesthesia, all episodes of nausea and vomiting were recorded and safety assessment were performed.

The treatment groups were comparable with regard to patient demographics. The incidence of postoperative vomiting was 17% with midazolam 50 µg/kg (P = .042) and 13% with midazolam 75 µg/kg (P = .019), compared with placebo (40%). No difference in the incidence of postoperative nausea was found among the 3 groups. No clinically important adverse events, such as extrapyramidal signs, were found in any of the groups. None of the patients experienced drowsiness or excessive sedation.

Midazolam 50 µg/kg is as effective as midazolam 75 µg/kg for preventing postoperative vomiting, but not postoperative nausea, during the first 24 hours after anesthesia in patients undergoing thyroidectomy.