High-dose treatment with haloperidol: The effect of dose reduction

High doses of antipsychotic medications are sometimes prescribed in clinica l practice, although the efficacy and safety of such treatment have not bee n established. The purpose of this study was to determine whether high-dose , longterm antipsychotic treatment prescribed on the basis of clinical judg ment can be justified. Patients who were receiving high doses of haloperido l mere screened, and those patients whose plasma levels were at least 15 ng /mL mere randomly assigned to an experimental group (N = 11) or to a contro l group (N = 12). The experimental group underwent a dose reduction to achi eve the target plasma level of 10 ng/mL. The reduction was gradual over a p eriod of 12 weeks. The control group treatment was maintained at the origin al level. Both groups were then followed up for another 16 weeks, during wh ich the plasma levels of haloperidol were kept constant. The study used dou ble-blind procedures. Both groups showed an average slight symptom reductio n. There was no significant difference in the severity of symptoms between the two groups at any time point. The dose reduction had no apparent advers e effects, Thus, the results of this study did not provide justification fo r high-dose, long-term antipsychotic treatment. However, these results must be interpreted with caution because the sample studied here was small and biased.