Olanzapine plasma concentrations and clinical response in acutely ill schizophrenic patients

Perry P.J.; Sanger T.; Beasley C.

S-415 Pharmacy, University of Iowa, Iowa City, IA 52242, USA

Olanzapine is an atypical antipsychotic effective in the treatment of schizophrenic patients. After a 2- to 9-day placebo lead-in, 79 inpatients with schizophrenia according to DSM-III-R criteria were placed on an olanzapine dosage of 10 mg/day or 1 mg/day for up to 6 weeks. Blood samples were obtained weekly during this period. Receiver operating characteristic curve analyses of Brief Psychiatric Rating Scale (BPRS) and Positive and Negative Syndrome Scale rating scale data suggested a minimum effective therapeutic concentration of 9 ng/mL. Using an intent-to treat analysis, 45% of the patients with olanzapine plasma concentrations £ 9.3 ng/mL responded (£ 20% decrease in BPRS), whereas only 13% of the patients with concentrations < 9.3 ng/mL responded. Use of olanzapine plasma concentrations of > 9 ng/mL as a predictor for treatment response in acutely ill schizophrenic patients is practicable because this therapeutic marker significantly increases the likelihood of a patient responding to olanzapine.

Keywords: schizophrenia (link) drug therapy; drug blood level; acute disease; receiver operating characteristic; drug safety; high performance liquid chromatography; extrapyramidal symptom (link) side effect; human; male; female; major clinical study; clinical trial; randomized controlled trial; controlled study; article; priority journal

J. CLIN. PSYCHOPHARMACOL. 17/6 (472-477) 1997