Efficacy and side effects of haloperidol in psychotic patients: oral versus intravenous administration

It is a commonly held view among clinicians that intravenously administered haloperidol has a greater antipsychotic effect than oral haloperidol. To test this hypothesis, the authors carried out a double- blind study on patients with acute schizophrenia and patients with schizophreniform or schizoaffective (with manic features) psychoses. Using biologically equivalent doses, they found that intravenously administered haloperidol was slightly more effective during the first 3 hours; thereafter the route of administration did not make a difference in effectiveness.