A post hoc analysis of transitioning to oral treatment with olanzapine or haloperidol after 24-hour intramuscular treatment in acutely agitated adult patients with schizophrenia

Abstract

Background: Acutely agitated patients with schizophrenia might require treatment with IM antipsychotics, followed by a transition to oral medication.

Objective: The aim of this study was to assess the relationship between 24-hour IM and transitional oral dosages of 2 antipsychotic medications, olanzapine and haloperidol.

Methods: This post hoc analysis used data from a multinational, double-blind, randomized, placebo-controlled study comparing the efficacy of olanzapine, haloperidol, and placebo in acutely agitated inpatients aged > or =18 years with schizophrenia conducted at hospitals in 13 countries. Patients received 1 to 3 IM injections of olanzapine 10 mg or haloperidol 7.5 mg over 24 hours (IM phase), followed by 4 days of oral treatment with 5 to 20 mg/d of either antipsychotic (oral phase). Study patients were grouped according to which drug they received, and subgrouped based on whether they received a single or multiple IM injections. Rates of transition to lower (5-10 mg/d) versus higher (15-20 mg/d) dosages were compared within and between treatments.

Results: Data from 236 patients were analyzed (olanzapine, 121 patients [76 men, 45 women; mean (SD) age, 38.4 (12.2) years; mean (SD) weight, 74.9 (18.5) kg]; haloperidol, 115 patients [80 men, 35 women; mean (SD) age, 38.0 (10.2) years; mean (SD) weight, 75.4 (18.7) kg]). At the end of the IM phase, the rate of haloperidol patients who were transitioned to lower oral doses was significantly higher in the single-injection subgroup compared with the multiple-injection subgroup (P = 0.03); this difference was not found in the group receiving olanzapine. At day 4 of oral treatment, the rates of patients in the olanzapine and haloperidol groups who were transitioned to higher oral doses were significantly higher in the single-injection subgroups compared with the multiple-injection subgroups (P = 0.002 and =0.003, respectively).

Conclusion: In this study, the proportion of agitated patients with schizophrenia who transitioned to higher dosages (15-20 mg) of olanzapine or haloperidol by day 4 of the oral switch was significantly greater in patients who were previously treated with a single IM injection of olanzapine (10 mg) or haloperidol (7.5 mg).right.