Pheniramine (INN, trade name Avil, among others) is an antihistamine with anticholinergic properties used to treat allergic conditions such as hay fever or urticaria. It has relatively strong sedative effects, and may sometimes be used off-label as an over-the-counter sleeping pill in a similar manner to other sedating antihistamines such as diphenhydramine. Pheniramine is also commonly found in eyedrops used for the treatment of allergic conjunctivitis.
|AHFS/Drugs.com||International Drug Names|
|Oral; injection (intramuscular or slow intravenous); topical (ophthalmic/nasal solution)|
|Metabolism||Hepatic hydroxylation, demethylation and glucuronidation|
|Chemical and physical data|
|Molar mass||240.343 g/mol|
|3D model (JSmol)|
Pheniramine is generally sold in combination with other medications, rather than as a stand-alone drug, although some formulations are available containing pheniramine by itself. As an example, TheraFlu/Neo Citran contains pheniramine.
Halogenation of pheniramine increases its potency 20-fold. Halogenated derivatives of pheniramine include chlorphenamine, brompheniramine, dexchlorpheniramine, dexbrompheniramine, and zimelidine. Two other halogenated derivatives, fluorpheniramine and iodopheniramine, are currently in use for research on combination therapies for malaria and some cancers.
|Enantiomers of pheniramine|
Pheniramine is a deliriant (hallucinogen) in toxic doses. Recreational use of Coricidin for the dissociative (hallucinogenic) effect of its dextromethorphan is hazardous because it also contains chlorpheniramine.