FDA asks for warning on some asthma drugs

WASHINGTON, June 15 (UPI) -- The U.S. Food and Drug Administration has asked manufacturers to include a precaution in the labeling of some asthma drugs called leukotriene modifiers.

The federal agency said the labeling should advise patients that some neuropsychiatric events have been reported by people taking montelukast (Singulair), zafirlukast (Accolate) and zileuton (Zyflo and Zyflo CR).

"Leukotrienes are chemicals the body releases in response to an inflammatory stimulus, such as when a person breathes in an allergen," the FDA said in a statement. "Montelukast and zafirlukast are leukotriene receptor antagonists that work by blocking leukotrienes. Zileuton is a leukotriene synthesis inhibitor, which works by stopping the formation of certain substances that cause swelling, tightening and mucus production in the airways."

The FDA said reported neuropsychiatric events include agitation, aggression, anxiousness, dream abnormalities, hallucinations, depression, insomnia, irritability, restlessness, suicidal thinking and behavior -- including suicide -- and tremors.