Controlling emesis related to cancer therapy.

Combinations of dopamine antagonists or high-dose metoclopramide with steroids can provide complete control of chemotherapy-related nausea and vomiting in up to 60-70% of patients undergoing high-dose cisplatin-based chemotherapy. High-dose metoclopramide probably acts as a 5-HT3 receptor antagonist, but because of its dopamine-receptor antagonism it is the cause of extrapyramidal side-effects. These compounds, and the agents used in combination with them, tend to cause sedation, an undesirable effect in the outpatient setting. Specific 5-HT3 receptor antagonists (ondansetron, granisetron, tropisetron) give a similar control of chemotherapy related nausea and vomiting, with minimum side-effects. These drugs can cause headaches and constipation and some have been related to transient liver enzyme abnormalities in cancer patients; however, disease and chemotherapy might also be the cause of the enzyme anomalies. Combinations of 5-HT3 receptor antagonists with steroids may provide a very high degree of protection.