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Azelastine
- indication:For the symptomatic treatment of seasonal allergic rhinitis and non-allergic rhinitis, as well as symptomatic relief of ocular itching associated with allergic conjunctivitis.
- pharmacologypharmacology:
- mechanism: Azelastine competes with histamine for the H1-receptor sites on effector cells and acts as an antagonist by inhibiting the release of histamine and other mediators involved in the allergic response.
- toxicity:
- absorprion: Absorption of azelastine following ocular administration was relatively low. Systemic bioavailability is approximately 40% after nasal administration.
- halflife: Elimination half-life (based on intravenous and oral administration) is 22 hours. Elimination half-life of the active metabolite, desmethylazelastine, is 54 hours (after oral administration of azelastine).
- roouteelimination: Approximately 75% of an oral dose of radiolabeled azelastine hydrochloride was excreted in the feces with less than 10% as unchanged azelastine. Azelastine hydrochloride is oxidatively metabolized to the principal metabolite, N-desmethylazelastine, by the cytochrome P450 enzyme system.
- volumedistribution: * 14.5 L/kg
- clearance: * 0.5 L/h/kg [symptomatic patients]