2 to 5 mg IM single dose initially; use if oral therapy is not appropriate; may administer as frequently as 1 hour intervals, though dosing every 4 to 8 hours is satisfactory for most patients. Max: 20 mg/day IM. Repeat doses based on clinical response and safety considerations. Geriatric patients may require a lower dose; use lower starting dose and titrate gradually. Use the lowest effective dose in all patients. Convert to oral therapy as soon as clinically indicated. Second generation antipsychotics with efficacy for this indication (oral or parenteral, ., risperidone, olanzapine, or ziprasidone), may be preferred due to cardiac and extrapyramidal risks of parenteral haloperidol. In some patients, the addition of a benzodiazepine may be needed. SWITCHING TO ORAL THERAPY: In general, the parenteral dose administered in the preceding 24 hours may be used as the total initial daily PO dosage. Thereafter, closely monitor and adjust oral dosage to efficacy and tolerance. Usually, the first oral dose should be given within 12 to 24 hours following the last IM dose.
Given these considerations, antipsychotic drugs should be prescribed in a manner that is most likely to minimize the occurrence of tardive dyskinesia. Chronic antipsychotic treatment should generally be reserved for patients who suffer from a chronic illness that 1) is known to respond to antipsychotic drugs, and 2) for whom alternative, equally effective, but potentially less harmful treatments are not available or appropriate. In patients who do require chronic treatment, the smallest dose and the shortest duration of treatment producing a satisfactory clinical response should be sought. The need for continued treatment should be reassessed periodically.