Background: A frequently used anxiolytic, midazolam, has recently been recognized for its
antiemetic activity during the perioperative period. This study sought to investigate the best
time to provide midazolam in order to decrease the frequency of postoperative nausea and
vomiting (PONV) without increasing the risk of sedation.
Methods: A total of 120 women aged 20–60 years who underwent laparoscopic gynecological
surgeries were distributed randomly to three groups: group M1 (n = 40) received intravenous
2 mg midazolam 15 min prior anesthesia induction, group M2 (n = 40) received intravenous
2 mg midazolam approximately 30 min prior surgery conclusion, and group C (n = 40) received
intravenous normal saline. The frequency of PONV and the rescue antiemetics needs were
measured as the primary outcomes during the first 24 hr postoperatively. The secondary
outcomes were the severity of nausea, timing of initial emetic attack, time of PACU discharge,
patient sedation, and pain scores.
Results: The frequencies of vomiting and rescue antiemetic use were lower in midazolam
groups than controls during early (0–2) and late (0–24) time periods after surgery (P < 0.05),
with insignificant difference between M1 and M2 groups. The timing of the first emetic episode
was significantly longer in M2 than in C groups (458.3 vs 128.8 minutes) (P < 0.01). Insignificant
differences with regard to frequency and severity of nausea, time of PACU discharge, and
sedation score were detected among the three groups.
Conclusion: Midazolam was effective in reducing PONV, whether it was given prior induction
of anesthesia or prior end of surgery, without influencing recovery duration or sedation level of
the patients.