Optimum management of nausea and vomiting in cancer chemotherapy.

Nausea and vomiting continue to be critical problems in cancer chemotherapy, although considerable progress has been made toward understanding the neuropharmacological mechanisms of vomiting and how chemotherapeutic agents and antiemetics affect these mechanisms. The principles of behavioural psychology have also been applied in an effort to understand and effectively manage these complications which have potentially serious consequences. For example, there is now some degree of rationality to our use of metoclopramide for cisplatin-induced nausea and vomiting, the use of combination antiemetic regimens, and use of lorazepam for the prevention (albeit unproven) of anticipatory nausea and vomiting. It must be admitted, however, that our approach is for the most part still empirical. Selecting an antiemetic programme is not a simple task. The emetogenic potential of the chemotherapy being used, the presence of coexisting diseases, the potential toxicity of the antiemetic drug and whether antiemetic therapy is to take place in the hospital or in an outpatient setting, the familiarity of the clinician with the various antiemetic therapies, and cost are all factors which need to be considered. Although phenothiazines remain the standard treatment, they are of little value against chemotherapy programmes that produce moderate or severe problems. Newer pharmacological approaches including butyrophenones, cannabinoids, metoclopramide, high-dose corticosteroids, and benzodiazepines have shown increased antiemetic efficacy, as have combinations of these agents which are directed against multiple sites of emetogenic activity. The role of behavioural therapies, which have been shown to be effective particularly in children and in anticipatory nausea and vomiting, needs to be more firmly established. Rather than recommending a given antiemetic programme for any particular chemotherapy, it is preferable to think in terms of initial approaches and how they can be modified. No one antiemetic programme is effective or safe in all situations.