Low-dose of olanzapine has ameliorating effects on cancer-related anorexia

Olanzapine (OLZ) has become well-known for its antiemetic effects on chemotherapy-induced nausea and vomiting. However, it remains unclear whether OLZ also has efficacy for treating cancer-related anorexia. This study, therefore, retrospectively examined whether or not OLZ administration affects the food intake in anorexic cancer patients who exhibit neither nausea nor vomiting.

Eighty patients prescribed OLZ were extracted from 951 inpatients who consulted with our palliative care team at Chiba University Hospital from April 2008 to March 2016. Their food intake described on a nursing record was compared before and after OLZ administration. The observation period was 3 days before and after the start of OLZ treatment, because most inpatients whose food intake increased were discharged in 3 days.

In those 80 patients, the average dose of OLZ for 3 days was 2.28±0.87 (mean±SD) mg/day. First, the food intake in 80 patients was significantly higher after than before starting OLZ, and the relative change in food intake was 149% on average (P<0.0001, Student's paired t-test). Second, OLZ increased the food intake even in 40 out of 80 patients without nausea or vomiting, and the relative change in food intake was 143% on average (P<0.001, Student's paired t-test). Third, the average food intake increased in 13 out of 40 patients who were prescribed 1.5 mg/day of OLZ, and the relative change in food intake was 124% on average (P<0.01, Student's paired t-test). There was no significant difference in food intake between a dose of 1.5 mg/day and a dose of >1.5 mg/day of OLZ (P=0.18, Welch's unpaired t-test).

We have herein reported OLZ's ameliorating efficacy in cancer-related anorexia at the low dose of 1.5 mg/day. Although our study has many limitations, low-dose OLZ can be a promising treatment for cancer-related anorexia.