Olanzapine combined with 5-hydroxytryptamine type 3 receptor antagonist (5-HT3 RA) plus dexamethasone for prevention and treatment of chemotherapy-induced nausea and vomiting in high and moderate emetogenic chemotherapy: a systematic review and meta-analysis of randomised controlled trials

We performed a pooled analysis to evaluate the efficacy and adverse events (AEs) of olanzapine combined with dexamethasone plus 5-hydroxytryptamine type 3 receptor antagonist (5-HT3 RA) compared with 5-HT3 RA plus dexamethasone for the prevention and treatment of chemotherapy-induced nausea and vomiting (CINV) in high and moderate emetogenic chemotherapy based on randomised controlled trials (RCTs). PubMed, EMBASE, Web of Science, the Cochrane Library, China Biomedical Literature database (CBM), WanFang Database, China National Knowledge Infrastructure (CNKI), and Chinese Science and Technology Periodical Database (VIP) (from their inception to April 2019) were searched to capture relevant articles. Relative risk with 95% confidence intervals for CINV and AEs were all extracted or calculated. Eleven studies with 1107 cancer patients were involved in this review. The pooled RR of delayed CINV (RR 0.50, 95% CI 0.38 to 0.66; p<0.01) were significantly decreased in the olanzapine group. The occurrence of insomnia was also statistically decreased, as was the rate of acute CINV (RR 0.60, 95% CI 0.48 to 0.75; p<0.01). However, only the percentages of CINV III and CINV IV were significantly decreased in the acute and delayed phases. Subgroup analysis demonstrated that the efficacy was not statistically significantly different between 5 mg and 10 mg olanzapine. Olanzapine significantly decreased the occurrence of CINV III and IV and insomnia in high and moderately emetogenic chemotherapy. Compared with 10 mg per day, 5 mg oral olanzapine may be more appropriate for patients with cancer.