Serum haloperidol concentrations and clinical response in acute psychosis

Steady state serum haloperidol concentrations measured by gas-liquid chromatography and a neuroleptic radioreceptor assay were compared to clinical response in 21 acutely psychotic inpatients. Serum concentrations measured by the two assay methods correlated well with each other, although the neuroleptic radioreceptor assay was much less sensitive. There was also a significant linear relationship between haloperidol dose (mg/kg/day) and steady state serum concentration. The correlation between haloperidol serum concentrations and clinical response after 2 to 3 weeks was nonlinear and most pronounced in the intermediate range (15 to 40 ng/ml). Further studies will be needed to establish with certainty the existence and exact limits of a therapeutic window.