Intensive treatment with haloperidol of treatment-resistant chronic schizophrenic patients

The authors treated 11 treatment-resistant schizophrenic patients with steadily increasing doses of haloperidol to determine the therapeutic range of plasma concentrations in such patients. Six patients responded, usually within a few weeks of treatment and at doses of 50 mg/day or less; plasma concentrations ranged between 17 and 42 ng/ml. Five patients were unresponsive, despite treatment for 13-22 weeks, doses of haloperidol of 180-270 mg/day, and plasma concentrations of 51-225 ng/ml. Doses greater than 150 mg/day appear unnecessary, because lesser doses generally provide plasma concentrations of 20-50 ng/ml. Failure to respond within 2 months of reaching such doses or plasma concentrations augurs for continued lack of response.