Purpose: Chemotherapy-induced nausea and vomiting (CINV) is a distressing chemotherapy-induced symptom that may adversely impact the quality of life of cancer patients.
Methods: We conducted a systematic search of the Pubmed, Bireme, and Cochrane databases for randomized clinical trials that were published in English and that evaluated the combination of adjunctive non-neurokinin 1 (NK1) antagonist drugs (i.e., neuroleptics, anticonvulsants, benzodiazepines, and cannabinoids) with 5-hydroxytryptamine 3 (5-HT3) antagonists for adult cancer patients who were scheduled to receive moderate or highly emetogenic chemotherapy. We employed the Review Manager (RevMan) Computer program Version 5.2 for statistical calculations.
Results: We included 13 studies with a total of 1,669 patients. We observed a higher complete protection for acute CINV with adjunctive medications (risk ratio (RR) = 0.55; 95% confidence interval (CI) 0.30-1.01; p = 0.05; I2 = 47%), which was not the case for the delayed period (RR = 0.89; 95% CI 0.73-1.10, p = 0.29, I2 = 15%). We also observed that these adjunctive medications significantly increased the complete control of nausea (RR = 0.72; 95% CI 0.55-0.95; p = 0.02, I2 = 83%) and vomiting (RR = 0.61; 95% CI 0.50-0.75; p < 0.00001; I2 = 60%). There was no subgroup analysis evidence of the superiority of any single group of adjunctive medications.
Conclusions: We conclude that adjunctive non-NK1 antagonist medications may be useful for CINV control. Prospective randomized studies incorporating these low-cost medications into new regimens combining 5-HT3 and NK1 antagonists may be warranted.