Abstract: Objective To evaluate the efficacy and safety of olanzapine in prevention of breakthrough chemotherapyinduced vomiting in cancer patients receiving highly emetogenic chemotherapy.
Methods Thirty-six cancer patients with chemotherapy related breakthrough vomiting in the first cycle were enrolled in this study. These patients were given olanzapine（10mg once daily, d1-d3）orally before the second cycle of chemotherapy to prevent explosive vomiting. The nausea and vomiting of patients were scored according to the national cancer institute common terminology criteria for adverse events. The test was used to compare the differences of vomiting scores before and after receiving olanzapine. Results The vomiting scores of the 36 cases were significantly decreased （10.1±0.9 vs. 18.2±1.2， P=0.032） after combined with olanzapine in prevention. 47.2％（17/36） of the patients no longer had explosive vomiting after receiving olanzapine and 75.0％ （9／12） of women patients no longer had vomiting after receiving olanzapine. The effective rate of olanzapine in prevention of vomitting was 80.0%. The main related side effects were dizziness and fatigue， and the incidences were 36.1％ and 30.6％， respectively. Conclusion Olanzapine can effectively reduce the incidence of chemotherapy related breakthrough vomiting， and release the symptom of nausea and vomiting in cancer patients.