For the symptomatic relief of allergic conditions including seasonal allergic rhinitis, perennial allergic rhinitis and chronic urticaria. Adequate studies have shown the beneficial effect of cetirizine as adjunct therapy in asthma. However, the exact mechanism is yet to be established.

Treatment with cetirizine at daily doses of 5 to 10mg in adults and in paediatric patients aged between 6-11years, reduced the symptoms of seasonal and perennial allergic rhinitis, and reduced the occurrence, severity and duration of hives and pruritus in patients with chronic idiopathic urticaria.

In mildly asthmatic patients, cetirizine hydrochloride at 5 to 20 mg blocked bronchoconstriction due to nebulized histamine, with virtually total blockage after a 20 mg dose.