Singulair contains montelukast and is a leukotriene receptor antagonist. As it works to prevent constriction of the bronchi and helps relieve the main symptoms of asthma such as coughing, difficulty and shortness of breath. Indications Of Use: - Prevention of asthma attacks and chronic treatment of asthma. - Relief of symptoms of seasonal or perennial allergic rhinitis. - Prevention of exercise-induced bronchoconstriction. Warnings: - Avoid taking the medicine if you are allergic to any of its ingredients. - The treatment must be adhered to with other types of asthma medicines, as this medicine is indispensable for them. - Do not take two doses of this medicine within 24 hours. - Take this medicine as it was prescribed by your doctor, and do not stop using it even if you feel better. - Avoid using aspirin and NSAIDs if you have asthma. A doctor should be consulted if it is used during pregnancy or breastfeeding. A valid prescription should be available upon delivery