Efficacy and tolerability of olanzapine in patients with schizophrenia in lithuania: A 13-week, multicenter, open-label, nonrandomized study

Abstract

Background: The atypical antipsychotic olanzapine has been approved for the treatment of schizophrenia in Europe since 1996 but has been used primarily as a second-line treatment to the less expensive typical agents. However, similar to other atypical antipsychotic drugs, olanzapine has a lower risk of inducing extrapyramidal symptoms, tardive dyskinesia, neuroleptic malignant syndrome, and sexual dysfunction compared with the typical antipsychotic drugs. Objective: The aim of this study was to determine whether patients with schizophrenia who have a poor response to their present antipsychotic therapy would show improvement when switched to olanzapine. Methods: This 13-week, multicenter, open-label, nonrandomized trial was conducted at 5 centers in Lithuania. Patients were started on oral olanzapine 10-mg tablets once daily, which could be adjusted by 5 mg/d in the dosing range of 5 to 20 mg/d. The primary efficacy measure was the total score on the Brief Psychiatric Rating Scale (BPRS), which was extracted from the Positive and Negative Syndrome Scale (PANSS). Efficacy response rate was defined a priori as the percentage of patients achieving ≥40% improvement in the BPRS total score. Secondary assessments included the PANSS total and BPRS and PANSS subscales and scores on the Clinical Global Impression-Severity of Illness (CGI-S), the CGI-Global Improvement (CGI-I), and the Patient Global Impression-Improvement (PGI-I) tests. Tolerability was primarily measured by assessing the incidence of treatment-emergent adverse events (AEs) according to the Udvalg fuer Kliniske Undersogelser (UKU) Side Effect Rating Scale and laboratory analyses. Results: Twenty-four patients (13 men [54.2%]; mean [SD] age, 32.4 [8.1] years) entered the study. Twenty-three (95.8%) of the 24 patients completed the study. The mean (SD) daily dosage of olanzapine was 11.40 (2.18) mg/d. The total mean (SD) BPRS score improved significantly from 37.8 (7.9) to 19.5 (13.7) (P < 0.001). The response rate was 58.3% (14/24 patients). The mean positive and negative BPRS scores and the mean total and subscale PANSS scores all improved significantly from baseline (P < 0.001). The mean (SD) CGI-S score improved significantly from 4.8 (0.8) at baseline to 3.5 (1.1) at end point (P < 0.001). Twenty-two patients (91.7%) showed improvement on the CGM scale. Similar improvement was found on the PGM scale. Treatment-emergent AEs occurred in 7 patients (29.2%). Improvement was found on 31 of the 48 UKU scale items; no change was shown on 15 items; and slight worsening was shown on 2 items. No clinical abnormalities were detected during the study. Conclusion: In this study of Lithuanian patients with schizophrenia, significant improvement was shown in all efficacy measures. In addition, olanzapine was well tolerated in these patients.