The Journal of clinical psychiatry
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Ondansetron is a 5-HT₃ receptor antagonist that has been approved for the prevention of nausea and vomiting associated with cancer chemotherapy, radiotherapy, and surgery. Ondansetron has also been studied in the treatment of many neuropsychiatric and medical conditions. The drug is commonly used off-label to treat nausea and vomiting of pregnancy (NVP) and hyperemesis gravidarum (HG). ⋯ Nevertheless, even if ondansetron is causally implicated in MCM risk, the absolute increase in risk, such as for orofacial clefts (by 0.03%) and ventricular septal defect (by 0.3%), is small. These small risks should be balanced against the risks associated with inadequately treated NVP/HG, and decision-making must be shared between clinician and patient. Repeated fetal scanning during the second trimester can help in the early detection of malformations, if present.