Federal regulators said today that they are continuing a probe into the psychiatric side effects of Singulair and similar asthma drugs. The Food & Drug Administration (FDA) began looking into the drugs’ potential psychiatric side effects last March, after it received several reports of suicidal behavior in patients taking Singulair.
Singulair, made by Merck & Co., is one of a class of drugs called leukotriene receptor antagonists. Singulair was approved to treat asthma and the symptoms of allergic seasonal allergies and to prevent exercise-induced asthma. Side effects of Singulair include gastrointestinal disturbances, hypersensitivity reactions, sleep disorders and increased bleeding tendency. Other leukotriene modifying medications include Accolate, which is also a leukotriene receptor antagonist and Zyflo and Zyflo CR, which are leukotriene synthesis inhibitors.
At the time of its March 2008 Early Communication, the FDA said it was working with Merck to further evaluate a possible link between the use of Singulair and behavior/mood changes, suicidality and suicide. The FDA requested that Merck evaluate Singulair study data for more information about suicidality and suicide. The FDA asked Merck, as well as AstraZeneca PLC, the maker of Accolate, and Cornerstone Therapeutics Inc., the maker of Zyflo, to submit post-marketing reports and other information for the review. The FDA said then that it anticipated that its safety review would take approximately 9 months.
FDA said Merck submitted results from 41 placebo-controlled clinical trials
Today, the FDA said Merck submitted results from 41 placebo-controlled clinical trials in which 9,929 patients were treated with Singulair and 7,780 were treated with a placebo. One adult patient out of 9,929 patients treated with Singulair had suicidal thoughts and there were no completed suicides. AstraZeneca submitted results from 45 placebo-controlled clinical trials in which 7,540 patients were treated with Accolate and 4,659 were treated with a placebo. The agency said one patient in the placebo group attempted suicide and another thought about suicide. No patients on Accolate reported any suicidal behavior. The FDA said information submitted by Cornerstone showed no suicidal behavior in either the Zyflo groups or placebo groups.
The FDA said that it appears the data submitted by the companies would suggest the products aren’t associated with suicide or suicidal behavior, however it noted that the trials weren’t designed to look at such behavior. The agency said it was continuing to review clinical trial data to assess other neuropsychiatric events such as mood and behavioral adverse events related to the drugs.
According to the FDA, most of the reports of other neuropsychiatric events are associated with Singulair. The agency said the clinical details of some Singulair reports are consistent with a drug-induced effect. Because of the paucity of reports involving Accolate and Zyflo, assessment of a drug–induced effect with these is limited, the FDA said. The agency is advising patients and doctors to monitor for the possibility of neuropsychiatric events associated with these drugs.
In the FDA Early Communication issued today, the agency said the safety review “may take months to complete.”