Objective   To investigate whether medical interventions on the gastrointestinal symptoms before chemotherapy-induced vomiting can relieve vomiting, and to identify the optimal measures to prevent chemotherapy-induced vomiting.

  Methods   Data from 229 cases undergoing chemotherapy were enrolled into this clinical study. Patients were randomly assigned into two groups at a ratio of 1:1, and recognized 5-HT3 receptor antagonists were administered to the patients during chemotherapy. In the intervention group, the protocols were also conducted during chemotherapy, which were designed as the combined agents metoclopramide, diphenhydramine, mziren capsule, and medroxyprogesterone in group 1 and only metoclopramide in group 2. Empirical medicines were given to the control group only when grade 2 (CTCEA v4.0) or stronger gastrointestinal symptoms occurred. The antiemetic efficacy was defined to have four levels, '0' means no vomiting, '1'means 1 to 2 episodes occurred in 24 hours, '2' means 3 to 5 episodes in 24 hours, and '3' means 6 or more episodes in 24 hours. Levels 0 and 1 are regarded as response to the treatment, and levels 2 and 3 as failure. The vomit prevention effects in the two groups were compared using the Multi-sample Rank Sum Test, and the effects in the subgroups were compared in a pairwise manner.

  Results   A total of 305 chemotherapeutic cycles were carried out, including 150 cycles in the intervention group: protocol 1 was performed using 76 cycles, and protocol 2 was performed using 74 cycles. There were 155 cycles in the control group. The multi-sample rank sum test (Kruskal-Wallis test) shows that the mean ranks of the antiemetic effects are 93.39, 150.13, and 183.60 in subgroups 1 and 2, and the control group, respectively. The difference between groups 1 and 2 was 56.74 (P < 0.001). The response rate of group 1 was significantly superior to that of group 2 (P=0.015). The Chi-square test shows that the differences of KPS before and after the chemotherapy are significant (P < 0.001).

  Conclusion   Medical intervention on the premonitory symptoms can significantly relieve chemotherapy-induced vomiting, improve the quality of life of the patient, and ensure a smooth progress in the chemotherapy. The vomiting relieving effect of the metoclopramide, diphenhydramine, mziren capsule, and medroxyprogesterone treatment is better than the single-agent protocol and should be recommended as the regimen of preventing chemotherapy-induced vomiting as multiple premonitory symptoms occur.