Nausea and vomiting are among the most distressing adverse effects of cancer chemotherapy. In the last 10 years considerable advances in the prevention of chemotherapy-induced emesis have been made. From an analysis of the results obtained in patients receiving moderately- to severely-emetogenic drugs the following guidelines in choosing the best antiemetic treatment can be given:
1. For the prevention of acute emesis induced by a high single dose of cisplatin (≥ 50 mg/m2) or by low doses (20 to 40 mg/m2) repeated for 4 to 5 days, the combination of ondansetron plus dexamethasone is the most efficacious and least toxic antiemetic therapy.
2. For the prevention of delayed emesis the combination of oral dexamethasone plus metoclopramide seems to offer the best protection, although over 40% of patients still experience delayed nausea and vomiting.
3. For the prevention of acute emesis induced by moderately emetogenic drugs, corticosteroids (dexamethasone or methylprednisolone) are efficacious and safe antiemetic agents. Although equally efficacious, the serotonin (5-HT)3 receptor antagonists, due to their higher acquisition costs, are indicated only in patients refractory to corticosteroids or in those who cannot use them.
Unresolved problems in antiemetic research include: (i) identification of the best antiemetic treatment for those areas of cancer chemotherapy where adequate data are lacking, such as high dose regimens for bone marrow transplantation; (ii) optimisation of treatment for the most widely used chemotherapy regimens; and (iii) identification of the best rescue treatment for patients who fail to respond to antiemetic prophylaxis.
Although many new 5-HT3 antagonists are currently being studied, the possible improvement in efficacy and tolerability brought about by these agents will probably only be marginal.