Montelukast has been generally well tolerated. Side effects, which usually were mild, generally did not require discontinuation of therapy.
Cardiovascular Effects: palpitations, allergic granulomatosis angiitis (Systemic eosinophilia with vasculitis and a clinical presentation consistent with Churg-Strauss. Symptoms may include eosinophilia, vasculitic rash, worsening pulmonary symptoms, cardiac complications and/or neuropathy).
Skin and subcutaneous tissue disorders: angioedema, bruising, erythema nodosum, atopic dermatitis, eczema, infection of skin and/or subcutaneous tissue, rash, urticaria.
Gastrointestinal Effects: abdominal pain, dental pain, diarrhea, gastroenteritis, indigestion, infection of tooth, nausea, pancreatitis, tonsillitis, vomiting.
Hematologic Effects: blood coagulation disorder (increased bleeding tendency).
Hepatic Effects: ALT/ AST levels raised, cholestatic hepatitis.
Immunologic Effects: hypersensitivity reactions, including anaphylaxis, varicella, and viral infection.
Neurologic Effects: asthenia, disorientated, dizziness, headache, hyperactive behavior, hypesthesia, insomnia, paresthesia, seizure, sinus headache, drowsiness, and tremor.
Ophthalmic Effects: conjunctivitis, myopia.
Otic Effects: Otalgia, Otitis, Otitis media.
Psychiatric Effects: aggressive behavior, agitation, altered behavior, anxiety, depression, dream disorder, feeling nervous, hallucinations, irritability, nightmares, restlessness, sleep disorder, somnambulism, suicidal thinking and behavior (including suicide).
Renal Effects: pyuria.
Respiratory Effects: bronchitis, acute cough, epistaxis, laryngitis, nasal congestion, nasal discharge, pharyngitis, pneumonia, respiratory tract infection, rhinitis, sinusitis, upper respiratory infection, wheezing.
Musculoskeletal and connective tissue disorders: arthralgia, myalgia including muscle cramps.
Other: fatigue, fever, influenza, malaise, traumatic injury.
Postmarketing experience: Blood and lymphatic system disorders: thrombocytopenia.
Psychiatric disorders: Obsessive-compulsive symptoms.