Management of chemotherapy-induced nausea and vomiting.

Cancer chemotherapy is associated with numerous toxicities such as nausea and vomiting (emesis). The frequency, onset, and duration of emesis depend largely on the emetogenic potential of specific agents. An exact mechanism for chemotherapy-induced emesis (CIE) is not known but is thought to occur through several noxious actions and numerous neuronal pathways. The three types of CIE are acute, delayed, and anticipatory. Nonchemotherapy causes of emesis should be considered before diagnosing CIE. Once the diagnosis is established, antiemetic regimens should be recommended based on characteristics of the patients and the agents. Phenothiazines, butyrophenones, cannabinoids, metoclopramide, corticosteroids, and benzodiazepines have been successful in preventing and treating CIE. Combinations of these drugs have also been successful and are still being investigated for improved emetic protection with fewer adverse reactions. Investigational agents such as serotonin antagonists may prove to be effective with few toxic effects. Despite the minimal information available on delayed and anticipatory nausea and vomiting, attempts should be made to treat them. Suggested guidelines for the management of CIE have been developed.