FDA Adds Antinausea, Cardiac Drugs to Watch List

June 25, 2013

The US Food and Drug Administration (FDA) has put a class of antiemetic drugs, including ondansetron (Zofran, GlaxoSmithKline, and Zuplenz, Par Pharmaceutical), on its latest quarterly list of products to monitor because of potential signals of an increased risk for serotonin syndrome.

The beta blocker metoprolol succinate (Toprol-XL, AstraZeneca) also landed on the list, posted on the FDA Web site last month, because of reports that suggested therapeutic ineffectiveness.

The agency received reports of possible adverse events for these products in the FDA Adverse Event Reporting System (FAERS) database during the first 3 months of 2013. The FDA cautions that an appearance on the watch list does not mean that the agency has concluded that the drug poses the health risk reported through FAERS. What it does mean is that the FDA will investigate whether there is a causal connection. If there is one, the agency would consider a regulatory action such as collecting more data to better characterize the risk, revising the drug's label, or requiring a risk evaluation and mitigation strategy.

Likewise, by adding a drug to the list, the FDA is not implying that clinicians should cease prescribing it or that patients should stop taking it, the agency says.

The antiemetics on the watch list belong to a subtype of serotonin blockers that bind to the 5-HT3 receptor. Clinicians prescribe them to prevent nausea and vomiting in patients undergoing chemotherapy for cancer. Serotonin syndrome, which was reported to FAERS in conjunction with these antiemetics, is caused by excessive levels of the neurotransmitter. It can be fatal. Symptoms include confusion, agitation, dilated pupils, headache, rapid heart rate, and changes in blood pressure and temperature.

The other drug on the latest watch list, metoprolol succinate, is used to treat angina, heart failure, and hypertension.

Potential Signals of Serious Risks/New Safety Information Identified by FAERS, January 2013 to March 2013

Product name: active ingredient (trade) or product class Potential signal of a serious risk/new safety information Additional information (as of May 1, 2013)
Metoprolol succinate (Toprol-XL, AstraZeneca) extended-release products Lack of therapeutic effect, possibly related to product quality issues FDA is continuing to evaluate this issue to determine the need for any regulatory action.
Serotonin-3 (5-HT3) receptor antagonist products: ondansetron (Zofran, GlaxoSmithKline, and Zuplenz, Par Pharmaceutical), palonosetron (Aloxi, Helsinn Healthcare), granisetron (Kytril, Hoffmann-La Roche) Serotonin syndrome FDA is continuing to evaluate this issue to determine the need for any regulatory action.


More information on FAERS and its quarterly watch list is available on the FDA Web site.


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