Promethazine reduces the permeability of capillaries, swelling of the mucous membranes, itching. Has adrenolytic, moderate peripheral and central cholinolytic action. Inhibits histamine-N-methyltransferase, blocks central histamine H3 receptors. Oppresses the central nervous system, has a sedative, anxiolytic, antipsychotic and hypnotic effect, lowers body temperature. Reduces the excitability of the vestibular receptors, eliminates dizziness. Has antiemetic effect.

Phenergan is an antiallergic, topical anesthetic, antihistamine, antipruritic, antiemetic, hypnotic, sedative on the basis of Prometnazine.