Promethazine is a first generation antihistamine and antipsychotic used to treat allergies, insomnia, and nausea.
The recreational drug purple drank often contains a combination of promethazine with codeine containing cold medication.
It was once widely used as an antipsychotic, although it is generally not used for this purpose now. It has approximately 1 of 10 the antipsychotic strength of chlorpromazine. It may also help with some symptoms associated with the common cold and may also be used for sedating people who are agitated or anxious.
