Efficacy of intramuscular haloperidol versus haloperidol plus promethazine in controlling aggressive behavior of psychiatric patients admitted to emergency rooms

The aim of this study was to compare the therapeutic and adverse effects of haloperidol to the combination of haloperidol and promethazine (antipsychotic + antihistamine) for controlling patients with aggressive or violent behavior referred to psychiatric emergency rooms. Using a double-blind randomized controlled trial, 100 psychiatric patients admitted to emergency room of Taleghani hospital, Tehran/Iran, randomly received intramuscular haloperidol or haloperidol plus promethazine. The patients were observed at 20, 40, 60, 120 minute intervals and then at 6, 12 and 24 hourly intervals to determine if they were tranquil or asleep, need for further injection, serious adverse effects, acute dystonia, akathisia, need for other medications, and need for admission to hospital based on clinical judgment. The mean age of patients was 36.25 years and 69% were male. Patients receiving promethazine plus haloperidol were more tranquil after 2, 6 and 12 hours and sustained sleep after hours 2 and 6. Adding promethazine to haloperidol decreased the need for repeated involvement of the psychiatrist on duty, using additional medications and hospital admission. Patients taking the combination of haloperidol and promethazine did not experience more adverse effects than those taking only haloperidol. The combination of haloperidol plus promethazine can be safely used in emergency rooms for controlling patient with agitation and aggressive behavior resulting in a sustained tranquilization or asleep and lower need for further intervention.