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Loratadine
- indication:A self-medication that is used alone or in combination with pseudoephedrine sulfate for the symptomatic relief of seasonal allergic rhinitis. Also used for the symptomatic relief of pruritus, erythema, and urticaria associated with chronic idiopathic urticaria in patients (not for children under 6 unless directed by a clincian).
- pharmacologypharmacology:
- mechanism: Loratadine competes with free histamine and exhibits specific, selective peripheral H<sub>1</sub> antagonistic activity. This blocks the action of endogenous histamine, which subsequently leads to temporary relief of the negative symptoms (eg. nasal congestion, watery eyes) brought on by histamine. Loratadine has low affinity for cholinergic receptors and does not exhibit any appreciable alpha-adrenergic blocking activity in-vitro. Loratadine also appears to suppress the release of histamine and leukotrienes from animal mast cells, and the release of leukotrienes from human lung fragments, although the clinical importance of this is unknown.
- toxicity: somnolence, tachycardia, and headache LD<sub>50</sub>=mg/kg (orally in rat)
- absorprion: Rapidly absorbed following oral administration (40% bioavailability)
- halflife: 8.4 hours
- roouteelimination:
- volumedistribution:
- clearance: