Antamin Mechanism of Action

Pharmacology: Pharmacodynamics: Chlorphenamine antagonises competitively the effects of histamine on H₁-receptors and also has weak antimuscarinic and moderate antiserotonin and local anaesthetic actions. It penetrates the brain and causes stimulation or sedation in animals.
Pharmacokinetics: Chlorphenamine maleate is almost completely absorbed after administration by mouth, peak plasma concentrations occurring at about 2.5 to 6 hours. The drug is widely distributed including passage into the CNS, with a volume of distribution of between 1 and 10L/KG. About 70% of chlorphenamine in the circulation is protein-bound. Chlorpheniramine undergoes some first pass metabolism and enterohepatic recycling. Chlorphenamine is extensively metabolised, principally to inactive desmethylated metabolites which are excreted primarily in the urine, together with about 35% unchanged drug. Only trace amounts are excreted in the faeces. The mean elimination half life has been reported to be about 30 hours, with mean values ranging from 2 to 43 hours.