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LEARNING OBJECTIVES
Upon completion of the chapter, the reader will be able to:
Identify common causes of nausea and vomiting.
Describe the pathophysiologic mechanisms of nausea and vomiting.
Distinguish between simple and complex nausea and vomiting.
Create goals for treating nausea and vomiting.
Describe attributes of available antiemetic therapies.
Recommend treatment regimens for nausea and vomiting associated with cancer chemotherapy, surgery, pregnancy, or motion sickness.
Outline a monitoring plan to evaluate treatment outcomes for nausea and vomiting.
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Nausea and vomiting result from complex interactions of the gastrointestinal (GI) system, the vestibular system, and the brain and have a variety of causes. Preventing and treating nausea and vomiting requires pharmacologic and nonpharmacologic measures tailored to individual patients and situations.
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EPIDEMIOLOGY AND ETIOLOGY
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Nausea and vomiting are symptoms that can be due to many different causes such as GI, cardiac, neurologic, and endocrine disorders and various medications (Table 21–1).1,2 Cancer chemotherapy agents are rated according to their emetogenic potential, and antiemetic therapy is prescribed based on these ratings. Radiation therapy can induce nausea and vomiting, especially when it is used to treat abdominal malignancies.3
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Oral contraceptives, hormone therapy, and opioids can cause nausea and vomiting.1 Some medications, such as digoxin, cause nausea and vomiting in a dose-related fashion, which may indicate excessive drug concentrations. Ethanol and other toxins also cause nausea and vomiting.
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Postoperative nausea and vomiting (PONV) occurs in 30% of surgical patients overall and in up to 70% of high-risk patients.4 Risk factors for PONV include female sex, history of motion sickness or PONV, nonsmoking status, and use of opioids postoperatively.5 The choice of anesthetic agents and duration of surgery may also contribute to PONV.4,5
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Nausea and vomiting of pregnancy (NVP) affects 50% to 80% of pregnant women, especially early in pregnancy.6 In 0.3% to 3% of pregnancies, this can lead to hyperemesis gravidarum, a potentially life-threatening condition of prolonged nausea, vomiting, and resultant malnutrition.6
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Nausea is the unpleasant subjective feeling of the need to vomit....