The U.S. Food and Drug Administration (FDA) is working with the drug company Merck to investigate a possible link between Merck's asthma and allergy drug Singulair and suicide risk associated with it. Meanwhile, "patients should not stop taking Singulair before talking to their doctor," the FDA said in a statement, adding that doctors should monitor patients for suicidal behavior and mood changes.

The federal agency said that the investigation may take nine months. Currently there is no proof that Singulair can lead to mood changes, suicidal behavior and suicide in patients

A study has revealed that people who have well-controlled mild asthma with twice-daily use of inhaled steroids may now be able to reduce inhaler use to once a day or switch to a daily pill.

Such sufferers of "mild" asthma are recommended to take additional drugs such as the inhaler albuterol, known as "rescue" therapy, to treat symptoms. The majority of people with asthma have a mild form of the disease, researchers note