Haloperidol and lorazepam combined: clinical effects and drug plasma levels in the treatment of acute schizophrenic psychosis.

In 61 acute schizophrenic patients the effects of haloperidol (HPL) and lorazepam combined vs. HPL alone and the interaction between these drugs were evaluated. Patients were assigned to groups randomly. The study design was open. Study duration was 28 days. Psychopathology was evaluated on the basis of BPRS scores. Extrapyramidal side-effects were rated according to Simpson and Angus (1970). Pharmacological parameters included serum levels of lorazepam, HPL, and reduced HPL. Mean daily lorazepam dosage was 0.05 mg/kg, mean HPL dosage 0.5 mg/kg. None of the patients treated with lorazepam and HPL achieved better BPRS total or subscores, nor did their condition improve faster than in patients treated with HPL alone. A significant linear relationship between lorazepam serum levels and oral dosage was found, but none between lorazepam serum levels and BPRS total score, subscore reduction, or extrapyramidal side-effects. The authors conclude that beneficial effects of lorazepam in the treatment of acute psychosis are scant and may not justify the risks incurred with routine comedication of lorazepam.