FDA Probes Suicides With Singulair Drug

The company said it recently added reports of suicide to Singulair's label, which already listed suicidal thinking and behavior as reported side effects.

In clinical trials of asthma patients, the most common side effects were headache, flu, abdominal pain and cough.

FDA said it is also reviewing reports of side effects with rival drugs, such as Accolate and Zyflo. Their labeling does not contain language about suicide.

Dr. Rauno Joks, an allergy specialist, said Thursday Singulair is generally well tolerated by his patients.

"Some of them have headaches with it but nothing I could imagine developing into depression or suicide," said Joks, head of the allergy division at State University of New York's Downstate Medical Center.

Joks said he will continue prescribing the drug because there are few alternatives for asthma patients beyond inhalable steroids, the standard treatment for the disease.

Shares of Merck Inc. fell 1 cents Thursday to $44.77 in after hours trading, following an earlier close at $44.78, up 8 cents for the day.