High-dose olanzapine versus standard-dose olanzapine: Effect on all-cause readmission rates in adult psychiatric patients.

INTRODUCTION: Olanzapine doses in adults with treatment-resistant schizophrenia or treatment-resistant schizoaffective disorder have been compared in a few open-label trials, with higher doses associated with increased symptom improvement. The most significant adverse effects observed at off-label doses above 30 mg/day have been weight gain, sedation, or drowsiness. METHODS: This single-center, retrospective cohort study aimed to evaluate patient factors and outcomes in adult patients admitted to a county psychiatric hospital that received high-dose olanzapine therapy (HD-olanzapine, ≥40 mg/day) compared with standard-dose olanzapine (SD-olanzapine, 5-30 mg/day). Patients 18 years or older were included if they received at least 5 days of scheduled olanzapine treatment for psychotic symptoms or psychosis while admitted. RESULTS: Subjects on HD-olanzapine (n = 139) and SD-olanzapine regimens (n = 70) were on average 35 years of age, and most were White. There was no statistical difference regarding 30-day all-cause readmissions, 30-day all-cause emergency-treatment service visits, or average duration of olanzapine therapy. The average length of stay was longer in the HD-olanzapine group (31.3 days vs 14.5, P = 0.009). Constipation was more common in the HD-olanzapine group (8.6% vs 1.4%, P = 0.0418). DISCUSSION: Although 30-day all-cause readmissions and emergency-treatment service visits were similar between groups, patients who received olanzapine doses of 40 mg/day or greater for at least 5 days of treatment experienced significantly longer average length of stay and more constipation during an admission.