25 - Nausea and Vomiting

Abstract

Nausea and vomiting are one of the more common complaints presenting to the emergency department (ED). These are symptoms of a myriad of diseases that can affect multiple organ systems and therefore a thorough history and physical exam and select testing should be done to discover the underlying cause. Patients with a small amount of vomiting do not require blood testing; however patients with prolonged vomiting should have their electrolytes and renal function checked and corrected as needed. A pregnancy test is required in all women of childbearing age. There is no single medication that has been definitively shown to be superior for undifferentiated vomiting or vomiting due to gastrointestinal disorders, and therefore choice of medication is based on the lowest side effect profile. The first-line agent is ondansetron. This can be substituted for metoclopramide or prochlorperazine if there is a contraindication to ondansetron, such as a prolonged QT interval. Specific conditions have medications that treat both the underlying cause and the vomiting and should be used in those cases. These include metoclopramide or prochlorperazine for migraine headache and antihistamines such as meclizine for vertigo. In hyperemesis gravidarum, ondansetron should be reserved for second line due to weak evidence for fetal anomalies. Cannabinoid hyperemesis syndrome is being increasingly recognized. While general antiemetics can be attempted, patients will often need a combination of haloperidol or lorazepam with topical capsaicin cream for symptom control. Cessation of marijuana is the definitive treatment.