The U.S. Food and Drug Administration said Friday it was updating the label of Merck & Co.'s (MRK) Singulair and similar asthma medications to discuss reports of neuropsychiatric events such as agitation, depression, insomnia and suicidal thinking.

The new labeling also applies to Accolate by AstraZeneca PLC (AZN) and Zyflo, by Cornerstone Therapeutics Inc. (CRTX).

The FDA said in a posting to its Web site that "patients and healthcare professionals should be aware of the potential for neuropsychiatric events with these medications."

Singulair, one of Merck's top-selling products, is approved to treat asthma and allergies while Accolate and Zyflo are approved to treat asthma.

-By Jennifer Corbett Dooren, Dow Jones Newswires; 202-862-9294; jennifer.corbett@dowjones.com