Sulpiride and haloperidol in schizophrenia: a double-blind cross-over study of therapeutic effect, side effects and...

In a double-blind cross-over trial, 20 chronic schizophrenic patients were treated with sulpiride and haloperidol in two 12-week periods. The final median dose of sulpiride was 2000 mg/day (range 800-3200) and of haloperidol 12 mg/day (range 6-24). Sulpiride had an antipsychotic effect and therapeutic profile not significantly different from that of haloperidol. In spite of the high doses of sulpiride, extrapyramidal side-effects were seen less frequently during the first four weeks of the sulpiride period than during the corresponding haloperidol period (P less than 0.05), whereas autonomic side-effects were equally rare for both drugs. A positive correlation was found between daily dose and plasma concentration of both sulpiride (P less than 0.001) and haloperidol (P less than 0.05), but no correlation could be established between clinical effects and plasma levels of either neuroleptic.