Drug treatment of adults with nausea and vomiting in primary care

What drugs are available and how do they work?

Nausea and vomiting are a common reason for patients to seek treatment in primary care, which we take here to include general practice and the emergency department. Identification and management of underlying problems are important, if these are apparent on clinical grounds. This article will focus on common causes in primary care such as gastroenteritis (usually viral), adverse drug reactions, pregnancy, vestibular disorders, and motion sickness. Other causes of nausea and vomiting such as postoperative, chemotherapy and radiotherapy associated, and specific conditions such as migraines are briefly discussed but are beyond the scope of this article.

Although still incompletely understood, nausea and vomiting are thought to follow activation of a medullary “vomiting centre,” by either afferent input from the gastrointestinal tract due to presence of local irritants or stimulation of the central chemoreceptor trigger zone by circulating emetogenic substances; however, other pathways exist. Dopamine and serotonin seem to be key transmitters both centrally and in the gastrointestinal tract.

Surveys of emergency physicians in Australia and the United States identified the most commonly prescribed agents as metoclopramide, prochlorperazine, promethazine, droperidol, and ondansetron.1 2 Anecdotally, cyclizine and …