Emedastine is an antihistamine used in eye drops to treat allergic conjunctivitis. [Wikipedia]
Indication
For the temporary relief of the signs and symptoms of allergic conjunctivitis.
Pharmacology
Emedastine is a relatively selective H1-receptor antagonist.
Toxicity
Somnolence and malaise have been reported following daily oral administration.
Affected Organisms
Humans and other mammals
Biotransformation
Two primary metabolites, 5-hydroxyemedastine and 6-hydroxyemedastine, are excreted in the urine as both free and conjugated forms. The 5'-oxoanalogs of 5-hydroxyemedastine and 6-hydroxy-emedastine and the N-oxide are also formed as minor metabolites.
Absorption
Ophthalmic use of emedastine usually does not produce measurable plasma concentrations.
Half Life
The elimination half-life of oral emedastine in plasma is 3-4 hours.
Elimination
Approximately 44% of the oral dose is recovered in the urine over 24 hours with only 3.6% of the dose excreted as parent drug. Two primary metabolites, 5- and 6-hydroxyemedastine, are excreted in the urine as both free and conjugated forms.
1-Methyl-1,4-diazepane in which the hydrogen attached to the nitrogen at position 4 is substituted by a 1-(2-ethoxyethyl)-1H-benzimidazol-2-yl group. A relatively selective histamine H1 antagonist, it is used as the difumatate salt for allergic rhinitis, urticaria, and pruritic skin disorders, and in eyedrops for the symptomatic relief of allergic conjuntivitis.
