Singulair tablet ingredients: "Before taking Montelukast, tell your doctor or pharmacist of all prescription and nonprescription products you may use which stimulate liver metabolism. This medication is not recommended in children less than 15 years old. The body that trigger allergic and asthmatic reactions. The active ingredient in the drug which is highly selective in inhibiting the action of leukotriene. We offer all the different potencies of tablets, which are to be administered differently. The original side effects, headache, nausea, vomiting, heartburn, hives and hoarseness of voice. Do not decrease or stop any asthma medicine unless instructed your doctor. Do not decrease or stop any asthma medicine unless instructed your doctor. This medication, tell your doctor or pharmacist if you are allergic to it or if you have any other allergies."