Background Just like many other medications, ondansetron can prolong the QTc interval on an electrocardiogram. In fact, the FDA released a Drug Safety Communication in 2012 recommending against IV doses > 16 mg to help limit the risk. A prospective, observational study in 40 cardiac patients (heart failure or ACS) found that ondansetron 4 mg … Continue reading Ondansetron and QTc Prolongation: Clinical Significance in the ED