What is "promethazine"

n. A first-generation H1 receptor antagonist, antihistamine and antiemetic medication with strong sedative effects.

n. antihistamine (trade name Phenergan) used to treat allergies; also an antiemetic used to treat motion sickness [syn: Phenergan]

Promethazine is a neuroleptic medication and first-generation antihistamine of the phenothiazine family. The drug has strong sedative and weak antipsychotic effects. It also reduces motion sickness and has antiemetic and anticholinergic properties (via its action on the Dopamine receptor D2). In some countries it is prescribed for insomnia when benzodiazepines are contraindicated. It is available in many countries under many brand names. Promethazine was developed in the mid 1940s when a team of scientists from Rhône-Poulenc laboratories were able to synthesize it from phenothiazine and a diamine side chain of diphenhydramine.