The Food and Drug Administration wants 14 drugmakers to check their study data to see if use of epilepsy drugs results in suicidal behavior or thoughts.
The FDA requested the reviews last month and gave the drugmakers six months to respond.
The request is similar to one the FDA made in 2003 regarding antidepressants and suicidal behavior in children. That review resulted in a “black box” warning, the FDA’s toughest, on the drugs’ labels last year. This is only the second review of that type, says Robert Temple of the FDA’s Center for Drug Evaluation and Research.
U.S. sales of anti-seizure drugs, including No. 1-seller Neurontin, made by Pfizer, and No. 2 Topamax from Ortho-McNeil Pharmaceutical, were the fifth-largest drug category last year, says research firm IMS Health. That’s largely because they’re used for many ailments other than epilepsy, which affects an estimated 2.7 million Americans. Neurontin is most often prescribed for pain. Topamax also prevents migraines.
The FDA says it’s doing the review because, as it learned with antidepressants, links between medications and adverse events can be missed “if you don’t look properly,” Temple says. The FDA review was first reported by the Boston Globe Wednesday.
The agency also has been pressed by New York law firm Finkelstein & Partners. It asked the FDA last year to add a black box suicide warning to Neurontin and says it has given the FDA 261 reports of people who committed suicide while on Neurontin. None had attempted suicide before, says attorney Andrew Finkelstein. Half took Neurontin for pain, he says.
Finkelstein has filed 73 personal injury lawsuits against Pfizer regarding Neurontin. Finkelstein says FDA drug reviewers in 1992 two years before Neurontin hit the market concluded the drug’s safety profile was good, but that less common, serious adverse events would limit its usefulness. One concern was that depression in people with epilepsy might worsen and lead to suicide. The FDA is reviewing that report, Temple says.
More than 10 million people have taken Neurontin, Pfizer says. The drug’s prescribing information, a 29-page document that goes to doctors, mentions “suicide gesture” as a rare adverse event, meaning it occurs in fewer than 1% of 1,000 patients. Pfizer spokesman Paul Fitzhenry says Neurontin adverse event reports over the past decade “show no link between Neurontin and suicidal thoughts or behavior.”
Last year, Pfizer division Warner-Lambert pleaded guilty to illegally marketing Neurontin to treat ailments for which it was not FDA approved. Although the marketing occurred in the mid-1990s, before Pfizer owned Warner, Pfizer paid $430 million in fines to settle the Justice Department’s allegations.
Neurontin is FDA-approved to treat epilepsy when used with another drug and for pain related to shingles. But doctors can prescribe drugs for whatever they want, and prosecutors say the illegal promotion boosted Neurontin sales so that 94% were for non-FDA approved conditions by 2002.
Gregory Barkley, an epilepsy specialist at Henry Ford Hospital in Detroit, says he would not be surprised if the review shows high rates of suicidal behavior. People with epilepsy have about twice the rate of depression as the general population, he says, and depression rates are also high among bipolar patients, who may take anti-convulsants. “I doubt that one anti-convulsant will be any worse than others,” he says.
Neurontin sales fell 74% in the first quarter to $182 million because of new generic competition.