Postoperative nausea and vomiting remains one of the most disabling and undertreated complications of general anesthesia, affecting up to 80% of high-risk patients and significantly prolonging recovery. A well-established antipsychotic now appears to offer a surprisingly potent solution at a fraction of current antiemetic costs — with implications for how perioperative care protocols are designed.
This randomized controlled trial enrolled 135 women aged 18–50, all classified as ASA I or II physical status, undergoing elective laparoscopic gynecological procedures under general anesthesia — a population already at elevated PONV risk due to female sex, nonsmoking status, and inhalational anesthesia exposure. Participants were divided equally into three arms: placebo, 5 mg oral olanzapine (OL5), or 10 mg oral olanzapine (OL10) administered perioperatively. Within the 24-hour postoperative window, nausea occurred in 51% of placebo patients, 29% of the OL5 group, and just 7% in the OL10 group. Most strikingly, the OL10 arm recorded zero vomiting episodes, with only one patient requiring rescue antiemetics compared to eight in the control arm — a clinically meaningful difference in care burden.
Olanzapine's antiemetic properties are rooted in its broad receptor antagonism, particularly at dopamine D2, serotonin 5-HT2, and histamine H1 receptors — a mechanistic profile that overlaps with, and may surpass, standard antiemetics like ondansetron or droperidol acting on narrower pathways. Earlier oncology research established its efficacy against chemotherapy-induced nausea, but perioperative applications remain relatively underexplored. This trial adds controlled evidence to a growing niche literature suggesting surgical contexts may benefit similarly. Key limitations include the exclusively female, single-surgery-type cohort, modest sample size of 45 per arm, and the absence of longer-term sedation tracking beyond the immediate recovery window — olanzapine's sedative profile warrants scrutiny in outpatient or ambulatory surgical settings. Still, the dose-response clarity here makes this a genuinely informative contribution to multimodal PONV prophylaxis research.