Brands, Medical Use, Clinical Data
Brands / Synonyms
Allergefon; Arbinoxa; Carbinoxamine; Carbinoxamine Maleate; Clistin; Paracarbinoxamine; Paracarinoxamine; Rotoxamine; Twiston
For symptomatic relief of seasonal and perennial allergic rhinitis and vasomotor rhinitis.
Carbinoxamine is an antihistamine of the ethanolamine class. Ethanolamine antihistamines have significant antimuscarinic activity and produce marked sedation in most patients. In addition to the usual allergic symptoms, the drug also treats irritant cough and nausea, vomiting, and vertigo associated with motion sickness. It also is used commonly to treat drug-induced extrapyramidal symptoms as well as to treat mild cases of Parkinson's disease. Rather than preventing the release of histamine, as do cromolyn and nedocromil, carbinoxamine competes with free histamine for binding at HA-receptor sites. Carbinoxamine competitively antagonizes the effects of histamine on HA-receptors in the GI tract, uterus, large blood vessels, and bronchial muscle. Ethanolamine derivatives have greater anticholinergic activity than do other antihistamines, which probably accounts for the antidyskinetic action of carbinoxamine.
Mechanism of Action
Carbinoxamine competes with free histamine for binding at HA-receptor sites. This antagonizes the effects of histamine on HA-receptors, leading to a reduction of the negative symptoms brought on by histamine HA-receptor binding. Carbinoxamine's anticholinergic action appears to be due to a central antimuscarinic effect, which also may be responsible for its antiemetic effects, although the exact mechanism is unknown.
Biotrnasformation / Drug Metabolism
Patients with hypersensitivity or idiosyncrasy to any of its ingredients. Sympathomimetic amines are
contraindicated in patients with severe hypertension, severe coronary artery disease and patients on monoamine
oxidase (MAO) inhibitor therapy. Antihistamines are contraindicated in patients with narrow-angle glaucoma, urinary
retention, peptic ulcer and during an asthma attack.
Antihistamines may enhance the effects of tricyclic antidepressants, barbiturates, alcohol, and other CNS
depressants. MAO inhibitors prolong and intensify the anticholinergic effects of antihistamines. Sympathomimetic
amines may reduce the antihypertensive effects of reserpine, veratrum alkaloids, methyldopa and mecamylamine. Effects
of sympathomimetics are increased with MAO inhibitors and beta adrenergic blockers.