These highlights do not include all the information needed to use Ondansetron Injection safely and effectively. See full prescribing information for Ondansetron Injection. The anti-nausea drug Zofran is approved for the prevention of nausea and vomiting caused by cancer chemotherapy, radiation and surgery. Doctors also prescribe the medication to treat morning sickness, though studies offer conflicting results about its potential for causing birth defects. About one in every 33 babies is born with a birth defect. Not all birth defects can be prevented. But a woman can take steps to increase her own chance of having a baby with the best health possible. Zofran use during pregnancy has been shown to double the risk of cleft palate and fetal heart defects and may increase birth defect rates by as much as 34%. 0.15 mg/kg IV infused over 15 minutes beginning 30 minutes prior to the initiation of chemotherapy and repeat 4 and 8 hours later (3 doses total). The study investigates teratogenic risks with ondansetron (Zofran ®). Data from the Swedish Medical Birth Register combined with the Swedish Register of Prescribed Drugs were used to identify 1349 infants born of women who had taken ondansetron in early pregnancy, 1998–2012. While birth defects can develop at any time during pregnancy, most begin during the first trimester. Why? This is the time when a baby’s organs are first forming – the most crucial part of fetal development. Ondansetron is a carbazole derivative with antiemetic activity. As a selective serotonin receptor antagonist, ondansetron competitively blocks the action of serotonin at 5HT3 receptors, resulting in suppression of chemotherapy- and radiotherapy-induced nausea and vomiting. Zofran (Ondansetron) is used for treating or preventing nausea and vomiting caused by cancer treatments such as chemotherapy and radiation therapy. Ondansetron tablets are indicated for the prevention of nausea and vomiting associated with: highly emetogenic cancer chemotherapy, including cisplatin greater than or equal to 50 mg/m 2.