Efficacy of Olanzapine for Symptom Relief in Cancer Patients

Olanzapine is an atypical antipsychotic and is widely used for prophylaxis of chemotherapy-induced nausea and vomiting in cancer patients. Previous studies have suggested its potential efficacy for the relief of various symptoms in cancer patients, especially gastrointestinal and psychiatric symptoms. We retrospectively reviewed the prescription of olanzapine to cancer patients at our hospital. Between 2008 and 2020, olanzapine was prescribed to 41 patients for relief of symptoms associated with cancer other than prophylaxis of chemotherapy-induced nausea and vomiting. Of those patients, symptom relief was seen in 53.7%. Notably, olanzapine was effective in 13 of 14 patients with chemotherapy-induced nausea and vomiting refractory to guideline-recommended prophylaxis. Of 16 patients in whom this symptom was not relieved by olanzapine, 13 (81.3%) continued taking olanzapine even after it was judged ineffective. No treatment-related adverse events were seen in this study. Our observation implies good efficacy of olanzapine for refractory chemotherapy-induced nausea and vomiting and a tendency to continue olanzapine even in those for whom it was ineffective.