The US FDA is investigating a possible association between the use of Singulair (Montelukast) and behavior/mood changes, suicidality (suicidal thinking and behavior) and suicide. Singulair is a once-a-day medicine classified as as leukotriene receptor antagonists used to treat asthma and symptoms of allergic rhinitis.

Over the past year, the maker of Singulair, Merck & Co, Inc., has updated the prescribing information and patient information for Singulair to include the following post-marketing adverse events: tremor (March 2007), depression (April 2007), suicidality (suicidal thinking and behavior) (October 2007), and anxiousness (February 2008).

Due to the complexity of the analyses, FDA anticipates that it may take up to 9 months to complete the ongoing evaluations. As soon as this review is complete, FDA will communicate the conclusions and recommendations to the public.

If you are using Singulair under prescription, please do not stop your medication without speaking toy our allergist. This is merely a safety review and FDA has so far not decided whether there are regulatory actions necessary, nor is the FDA advising health care professionals to discontinue prescribing this product.

If you are using Singulair, you are encouraged to report side effects from the use of Singulair, Accolate, Zyflo, and Zyflo CR to the FDA's MedWatch Adverse Event Reporting program:

* on-line at [www.fda.gov/medwatch/report.htm];
* by returning the postage-paid FDA form 3500 [available in PDF format at [www.fda.gov/medwatch/getforms.htm] to 5600 Fishers Lane, Rockville, MD 20852-9787;
* faxing the form to 1-800-FDA-0178; or
* by phone at 1-800-332-1088.