PROMETHAZINE

also called 10-(2-dimethylaminopropyl)ph enot hiazine synthetic drug used to counteract the histamine reaction, as in allergies. Promethazine, introduced into medicine in the 1940s, is used in the form of its hydrochloride. It is administered orally in tablets and syrups and intramuscularly in an aqueous solution. Promethazine is effective in controlling the symptoms of hay fever, acute skin reactions (such as hives), and contact dermatitis (as from poison ivy). It also has been used in anti-emetic preparations (for the control of nausea such as occurs in motion sickness). The commonest side effect of promethazine is drowsiness.