Nausea and vomiting in advanced cancer.

Nausea and vomiting are relatively common in advanced cancer and is dreaded more than pain by patients. The history, pattern of nausea and vomiting, associated symptoms, and physical examination provides clues as to etiology and may guide therapy. Continuous severe nausea unrelieved by vomiting is usually caused by medications or metabolic abnormalities, while nausea relieved by vomiting or induced by eating is usually due to gastroparesis, gastric outlet obstruction, or small bowel obstruction. Drug choices are empiric or based on etiology. Metoclopramide has the greatest evidence for efficacy followed by phenothiazines and tropisetron. Corticosteroids have not been effective in randomized trials except in the case of bowel obstruction. Treatment of nausea unresponsive to first-line medications involves rotation to medications which bind to multiple receptors (broad-spectrum antiemetics), the addition of another antiemetic to a narrow-spectrum antiemetic (a serotonin receptor antagonist such as tropisetron to a phenothiazine), rotation to a different class of antiemetic (tropisetron for a phenothiazine), or in-class drug rotation. Venting gastrostomy, octreotide, and corticosteroids will reduce nausea and vomiting associated with malignant bowel obstruction.