Olanzapine (Zyprexa®) Treatment in Patients Pre-treated with other Antipsychotics: Pharmacovigilance Data from a Large Drug Utilization Observation (DUO) Study in Germany

Objective: To observe tolerability-related aspects of drug-utilization and outcome of olanzapine (Zyprexa®) treatment in daily practice in patients pre-treated with other antipsychotics. Method: Outpatients with schizophrenia (ICD-10) or other psychiatric disorders pre-treated with antipsychotic medication other than olanzapine participated in this noninterventional drug utilization observation (DUO) study. At baseline, demographics and tolerability of antipsychotic pre-treatment were documented for patients theoretically eligible for olanzapine treatment. Patients actually starting olanzapine (OLZ group) were followed-up in a 6-month observational phase. Tolerability data collected included adverse events, laboratory, EEG and ECG findings, extrapyramidal symptoms (EPS) and CGI tolerability ratings (CGI-T). Results: Of 3358 pre-treated patients documented at baseline, 1654 continued previous treatment, while 1704 started olanzapine and follow-up. Hospitalizations and side effects of previous medication, concomitant diseases and co-medication all were significantly higher in patients subsequently treated with OLZ. During the observation, 582 adverse events were reported in 24.4% of patients, with weight gain reported most frequently (13.6%). Over the 6-month observation, mean body weight increased by 2.6±5.0 kg. All other adverse events had incidences of <3%. Olanzapine was generally well tolerated, as supported by favorable CGI-T ratings (96% of patients not or only minimally impaired by adverse events). Conclusions: This naturalistic study suggested that olanzapine was generally well tolerated in outpatients with schizophrenia treated in community clinical practices and had a tolerability profile consistent with that found in previous controlled trials. Of note, this study involved a patient population with high EPS rates at baseline due to prior antipsychotic treatment (German J Psychiatry 2005;8:49-58).