Antiemetic use of olanzapine in patients with advanced cancer: results from an open-label multicenter study

INTRODUCTION: The antipsychotic drug olanzapine is effective against chemotherapy-induced nausea and targets multiple receptors known to be involved in the emetic reflex arch. The drug has a mean half-life of 30 h, which allows for a single daily administration and is therefore of interest in patients with advanced cancer suffering from nausea.

OBJECTIVES: To investigate the antiemetic effect and tolerability of olanzapine in patients with advanced cancer not receiving chemotherapy or irradiation.

METHODS: Patients with advanced cancer (no curable treatment options) with at least "moderate" nausea and/or one emetic episode within the last 24 h were included if they had not received chemotherapy or irradiation (last 2 weeks) and had no reversible causes of nausea/vomiting. Patients were administered 10 mg olanzapine daily for 5 days (the first day subcutaneously and the following 4 days orally). Nausea, vomiting, and adverse effects were assessed daily for 7 days. The primary efficacy parameter was nausea after 24 h.

RESULTS: Forty patients from four centers were included and all evaluable after 24 h. Thirty-six patients experienced some degree of improvement. The mean two-item N/V score (0-100) at baseline was 66 and improved to 21 and 24 after 24 h and 7 days, respectively. During the course of the study, the dose of olanzapine was reduced in three patients due to adverse events. Five patients were withdrawn from the study primarily due to progression of malignant disease or per patient's request.

CONCLUSIONS: Olanzapine appears effective and tolerable as an antiemetic in patients with advanced cancer. Future research should examine a lower dose (5 or 2.5 mg), preferably in a randomized controlled trial.