Nausea and vomiting in patients with cancer.

Nausea and vomiting in advanced cancer, occurring as a manifestation of the disease process or as a complication of drugs used for symptom control, can be controlled rapidly in most instances using the protocol described. This involves an informed appraisal of the cause or causes of nausea and vomiting, combined with application of knowledge of the mechanisms of emesis and the action of antiemetics. Different mechanisms appear to responsible for emesis after chemotherapy and irradiation and for anticipatory vomiting. Ondansetron combined with dexamethasone appears to be the most effective regimen for post-cisplatin emesis. For less emetogenic agents, dexamethasone alone, or in combination with ondansetron for refractory cases, gives good control. For the control of vomiting induced by single-fraction radiotherapy to the upper abdomen, ondansetron is very effective. Management of anticipatory vomiting should concentrate on prevention, but once vomiting is established, behavioral therapy and the amnesic properties of lorazepam may be used.