Antihistamines

ANTIHISTAMINES

Antihistamines or histamine antagonists are of three types:

·      H₁-receptor antagonists (classical antihistamines) lessen histamine-mediated symptoms of allergic reaction.

·      H₂-receptor antagonists reduce gastric acidity.

·      H₃-receptor antagonists have no therapeutic indication, and hence will not be discussed at all.

Examples (of drugs with antihistaminic properties)

Brompheniramine, chlorpheniramine, dexbrompheniramine, dexchlorpheniramine, dimethindene, pheniramine, pyrrobu-tamine, triprolidine, carbinoxamine, clemastine, dimenhy-drinate, diphenhydramine, diphenylpyraline, doxylamine, phenyltoloxamine, antazoline, methapyrilene, pyrilamine, thenyldiamine, tripelennamine, methdilazine, promethazine, trimeprazine, astemizole, azatadine, azelastine, cyproheptadine, desloratadine, diphenylpyraline, ebastine, emedastine, lorata-dine, mebhydrolin, olopatadine, phenindamine, terfenadine, buclizine, cetirizine, chlorcyclizine, cyclizine, hydroxyzine, meclizine, niaprazine.

Some of these have been discussed elsewhere (Consult Index).