Chlorpheniramine plasma concentration and histamine H1-receptor occupancy.
Article Details
- CitationCopy to clipboard
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
Drug Target Kind Organism Pharmacological Action Actions Chlorpheniramine Histamine H1 receptor Protein Humans YesAntagonistDetails - Drug Enzymes
Drug Enzyme Kind Organism Pharmacological Action Actions Chlorpheniramine Cytochrome P450 2D6 Protein Humans UnknownSubstrateInhibitorDetails