Nausea and Vomiting: a Palliative Care Imperative.

This review was undertaken to survey recent literature for research reports and comprehensive clinical reviews addressing the pharmacologic management of nausea and vomiting (N&V) in advanced cancer. The goal was to integrate findings in a comprehensive article that incorporates palliative care concepts into antiemetic treatment. There are few published studies of N&V in advanced cancer; such research may be limited by the multicausal nature of N&V and participant burden to patients with life-limiting disease. Most articles are written by oncologists who also specialize in palliative care, and those addressing adverse effects of drugs used as antiemetics are found in other literature. Articles addressing more novel therapies, like cannabinoids and medical marijuana, are uncommon in the oncology literature. N&V in patients with progressive or advanced cancer is often multicausal. Nausea is more common and persistent, and even mild nausea is bothersome and may cause anxiety or depression. The mechanisms of nausea and vomiting overlap, but different neural pathways constitute the final pathway for each-the brainstem for vomiting and higher brain regions for nausea. Common causes of N&V in advanced cancer include constipation, opioids, and malignant bowel obstruction. About 40% have undetermined causes and may be exacerbated by impaired gastric emptying, chemical imbalances, or other factors. Several drugs that have antiemetic effects and act at different receptors are used to palliate N&V. There is a paucity of research that supports palliative antiemetic choices, and other research is needed to define potential therapeutic strategies that capitalize on differences between nausea and vomiting.