Drug Use Review of Olanzapine for Psychiatric Outpatients at Srinagarind Hospital

ABSTRACT Background: Psychiatric disorders are common worldwide including Thailand. At present, olanzapine has been used very frequent to treat psychiatric patients and found to be very effective in both schizophrenic positive and negative symptoms. But the incidence report on olanzapine adverse drug reactions (ADR) is still limited. Objective: To study prescription pattern of olanzapine and its ADR in psychiatric patients. Method: This was a retrospective study to review medical records of all psychiatric out-patients treated with olanzapine at Srinagarind hospital, Faculty of Medicine, Khon Kaen University during January 1 st 2004 to December 31 st 2010. Results: There were 116 psychiatric out-patients receiving olanzapine. Their mean age was 48.24±18.31 years old. Sixty five patients (56.03%) had been prescribed olanzapine according to the indication(s) approved by the United States Food and Drug Administration (US FDA); of which 40.52%, 27.59%, 17.24% were for patients with mood disorders, schizophrenia and dementia of the Alzheimer’s type and other dementia respectively. The usual and median daily dosage of olanzapine was 5-20 mg/day and 7.5 mg/day respectively. Adverse effects of olanzapine included weight gain was 48.28%, insomnia was 5.17%, extrapyramidal symptoms was 2.59%, increased sleeping hours was 1.72% and constipation was 0.86%. Regarding process indicators, effectiveness monitoring was done in 6.89% and safety monitoring of olanzapine prescription: at least once a year of complete blood count monitoring and lipid profile monitoring once every five years were done in 16.38% and 17.24% of the patients respectively. Conclusion: The olanzapine prescription, during 2004 - 2010, for psychiatric outpatients at Srinagarind Hospital, according to US FDA approval was found in 56.03%, the daily dosage was 5-20 mg/day. The most common side effect was weight gain. The effectiveness was done in 6.89% and safety monitoring was assessed in less than one-fifth of the patients.