"Montelukast can cause different side effects at varying degrees such as gastrointestinal disturbances, hypersensitivity or allergic reactions, sleep disorders, stomach upset, diarrhea, cough, dizziness, headache, nausea, vomiting, heartburn, hives and hoarseness of voice. Singulair is a new type of medication for the prevention and long-term treatment of asthma[...]