Preliminary results from a recent clinical study suggest that a 32-mg single IV dose of ondansetron may affect QT prolongation, which could predispose patients to develop torsades de pointes. The FDA is now informing health care professionals and the public about this potential risk and GlaxoSmithKline has announced that the drug label will no longer recommend a 32-mg single dose.
The updated label will state that ondansetron (Zofran) can still be used in adults and children with chemotherapy-induced nausea and vomiting, but at a lower IV dose of 0.15 mg/kg administered every 4 hours for three doses. The label will also note that no single IV dose should exceed 16 mg, as well as new information from the clinical study, according to a press release.
Ondansetron is a 5-HT3 receptor antagonist used to prevent nausea and vomiting caused by cancer chemotherapy, radiation therapy and surgery. Patients who may be at particular risk for QT prolongation with ondansetron include those with congenital long QT syndrome, congestive HF, bradyarrhythmias or patients taking concomitant medications that prolong the QT interval.
The FDA will evaluate the final study results when available and will work with GlaxoSmithKline to explore an alternative single-dose regimen that is both safe and effective for the prevention of chemotherapy-induced nausea and vomiting in adults, according to the release.