Chlorpheniramine plasma concentration and histamine H1-receptor occupancy.

Article Details

Citation

Yasuda SU, Wellstein A, Likhari P, Barbey JT, Woosley RL

Chlorpheniramine plasma concentration and histamine H1-receptor occupancy.

Clin Pharmacol Ther. 1995 Aug;58(2):210-20.

PubMed ID
7648771 [ View in PubMed
]
Abstract

The plasma concentration-response relationship of the antihistamine chlorpheniramine is poorly characterized. This study examined concurrently the concentrations of chlorpheniramine and presence of H1-receptor antagonist in plasma after administration of 8 mg chlorpheniramine in normal volunteers. Six extensive metabolizers and five poor metabolizers, as judged by CYP2D6 phenotype (dextromethorphan metabolic ratio), were enrolled in the study. More than 80% occupancy of H1-receptors by antagonist in plasma was observed for 12 hours after the dose in extensive metabolizers and greater than 60% from 12 to 30 hours in poor metabolizers, when plasma concentrations had fallen below those that should result in 50% occupancy of receptors. The results suggest that (+/-)-chlorpheniramine plasma concentrations do not predict H1-receptor antagonist in plasma. In addition, a role is suggested for CYP2D6 in formation of a potent active metabolite of chlorpheniramine.

DrugBank Data that Cites this Article

Drug Targets
DrugTargetKindOrganismPharmacological ActionActions
ChlorpheniramineHistamine H1 receptorProteinHumans
Yes
Antagonist
Details
Drug Enzymes
DrugEnzymeKindOrganismPharmacological ActionActions
ChlorpheniramineCytochrome P450 2D6ProteinHumans
Unknown
Substrate
Inhibitor
Details