CompositionCetirizine (5 mg) SALT INFORMATIONCetirizine (5 mg) TYPICAL USAGE Allergic rhinitis, ocular symptoms like redness, lacrimation and itching. Urticaria, dermographism, atopic eczema and contact dermatitis, acute allergic reactions due to drugs, foods, insect bites. SIDE EFFECTS Somnolence, insomnia, malaise, headache, dizziness, GI discomfort, dry mouth, abdominal pain, diarrhoea, nausea, vomiting; occasional hypersensitivity, epistaxis, pharyngitis, bronchospasm. DRUG INTERACTION Risk of increased INR and epistaxis when taken together with warfarin. CNS depressants and anticholinergics may potentiate CNS depression of cetirizine. MECHANISM OF ACTION Cetirizine is a potent and highly selective antagonist of the peripheral histamine H1-receptor on effector cells in the GI tract, blood vessels and respiratory tract.