Pharmacological properties : תכונות פרמקולוגיות

Pharmacodynamic Properties

5.1 Pharmacodynamic properties
ATC Code: R06AB04
Chlorphenamine is potent antihistamine (H1 antagonist).
Antihistamines diminish or abolish the actions of histamine in the body by competative reversible blockade of histamine H1-receptor sites on tissues. Chlorphenamine also has anticholinergic activity.

Antihistamines act to prevent the release of histamine, prostaglandins and leukotrines and have been shown to prevent the migration of inflammatory mediators. The actions of chlorphenmine include inhibition of histamine on smooth muscle, cappillary permeability and hence reduction of oedma and wheal in hypersneitivity reactions such as allergy and anaphylaxis.

Pharmacokinetic Properties

5.2 Pharmacokinetic properties
Chlorphenamine is well absorbed from the gastro-intestinal tract, following oral administration. The effect develop within 30 minutes, are maximal within 1 to 2 hours and last 4 to 6 hours. The plasma half life has been estimated to be 12 – 15 hours.
Chlorphenamine is metabolised to the monodesmethyl and didesmethyl derivative. About 22% of an oral dose is excreted unchanged in the urine.