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Affinities of Brompheniramine, Chlorpheniramine, and Terfenadine at the Five Human Muscarinic Cholinergic Receptor Subtypes
Author(s) -
Yasuda Sally Usdin,
Yasuda Robert P.
Publication year - 1999
Publication title -
pharmacotherapy: the journal of human pharmacology and drug therapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.227
H-Index - 109
eISSN - 1875-9114
pISSN - 0277-0008
DOI - 10.1592/phco.19.6.447.31041
Subject(s) - terfenadine , pharmacology , muscarinic acetylcholine receptor , chemistry , atropine , anticholinergic , histamine h1 receptor , cholinergic , receptor , antagonist , medicine , biochemistry
Anticholinergic effects are presumed to be the mechanism for the efficacy of chlorpheniramine in symptomatic relief of the common cold. Terfenadine, a second‐generation antihistamine, reportedly lacks anticholinergic side effects. We evaluated affinities of two commonly used over‐the‐counter antihistamines, brompheniramine and chlorpheniramine, as well as terfenadine in comparison with atropine at the five human muscarinic cholinergic receptor subtypes using CHO cells stably transfected with the individual subtypes. Atropine was more potent than all three drugs at m1–m5 (p<0.01). No significant difference was observed between chlorpheniramine and brompheniramine. Atropine, brompheniramine, and chlorpheniramine could not discriminate between m1–m5. Terfenadine demonstrated subtype selectivity at m3. In vitro comparisons in human muscarinic receptor subtypes could potentially be used to predict clinical anticholinergic effects of antihistamines and to target receptor‐specific effects of such agents.