Effect of different doses of oral olanzapine to prevent postoperative nausea and vomiting after laparoscopic surgery in high-risk patients: A randomised controlled trial.

Background: We conducted this study to compare the efficacy of oral 10 and 5 mg olanzapine for the prevention of postoperative nausea and vomiting.

Methods: Notably, 135 female patients between the ages of 18 and 50 years, classed as American Society of Anaesthesiologists I and II, who underwent elective laparoscopic gynaecological surgery under general anaesthesia were randomly assigned to one of three groups (45 each) to receive perioperative 5 or 10 mg oral olanzapine (OL5 and OL10 groups), or a placebo (in the control group). Postoperation, we recorded the occurrence and severity of postoperative nausea and vomiting within 24 h, the number of patients who received antiemetics and any associated side effects.

Results: Postoperative nausea was more prevalent in the control group (23 patients) than in OL5 and OL10 groups (13 and three patients, respectively); Group OL10 had the lowest severity of nausea. There was no incidence of vomiting in the OL10 group, and only one patient required antiemetics; in the OL5 group, three patients required antiemetics and eight patients in the control group needed antiemetics.

Conclusion: Olanzapine 10 mg had a higher effect than the lower concentration of 5 mg or control in reducing the incidence of postoperative nausea and vomiting in the first postoperative 24 h.