WASHINGTON -- The 32-mg dose of the anti-nausea drug ondansetron (Zofran) has been pulled from the market because of concerns about cardiac problems, the FDA announced Tuesday.
Ondansetron is approved for preventing chemotherapy-induced nausea and vomiting, and, in lower doses, for postoperative nausea and vomiting. The 32-mg formulation is given as a single intravenous dose.
"FDA does not anticipate that removal of the 32-mg intravenous dose of ondansetron currently sold as pre-mixed injections will contribute to a drug shortage of IV ondansetron, as the 32-mg dose makes up a very small percentage of the current market," the agency said in a statement.
In June, the FDA warned that the 32-mg dose should be avoided due to the risk of QT interval prolongation, which can lead to torsades de pointes, a potentially fatal arrhythmia.
"FDA continues to recommend the intravenous regimen of 0.15 mg/kg administered every 4 hours for three doses to prevent chemotherapy-induced nausea and vomiting," Tuesday's statement continued. "Oral dosing of ondansetron remains effective for the prevention of chemotherapy-induced nausea and vomiting. At this time, there is not enough information available for FDA to recommend an alternative single IV dose regimen."
Prior to the June warning, the FDA had indicated that it was investigating the arrhythmogenic potential of ondansetron in collaboration with the drug's maker, GlaxoSmithKline.
Preliminary results of a study ordered by the FDA found a maximum mean difference in QTcF of 20 msec after the 32-mg IV dose. An IV dose of 8 mg, on the other hand, led to a mean maximum QTcF difference of 6 msec.