haloperidol + promethazine

Haloperidol + promethazine is a fixed-dose combination of two drugs used primarily for the rapid tranquillisation of acutely agitated or violent patients, especially in psychiatric emergency settings. Haloperidol is a first-generation (typical) antipsychotic that acts mainly as a dopamine D2 receptor antagonist, reducing psychotic symptoms and agitation[6]. Promethazine is a first-generation antihistamine with sedative properties, acting as an antagonist at histamine H1 receptors and also possessing anticholinergic effects[10]. The combination enhances sedation, reduces the risk of extrapyramidal side effects (such as acute dystonia), and provides more rapid calming than haloperidol alone or some benzodiazepines[1][2][4][5]. This regimen is widely used in countries such as India and Brazil for behavioural emergencies. The addition of promethazine to haloperidol improves safety by lowering the incidence of serious adverse events compared to haloperidol monotherapy[2][5].