Singulair is taken to prevent and treat asthma. The oral tablets are for asthma patients age 15 years and older, and the chewable tablets are for pediatric patients 2 years of age and older. Do not take Singulair to relieve an asthma attack. It is not a replacement for the quick help that short acting inhalers provide during an asthma attack. It is very important that you continue taking your other asthma medicines unless your health care provider tells you to stop.