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Nausea & Vomiting

Taylor Riggs


VOMMIIT mnemonic

  • Vestibular: Labyrinthitis, vestibular neuritis, meniere’s disease, cerebellar stroke

  • Obstruction: adhesions, hernia, volvulus, constipation, gastric outlet obstruction

  • Motility: gastroparesis, GERD, autonomic dysfunction

  • Medications: antibiotics, SSRI, opioids, cannabinoid hyperemesis

  • Infection: gastroenteritis, hepatitis, pyelonephritis, cholecystitis

  • Inflammation: PUD, pancreatitis

  • Toxins: uremia, ketoacidosis, hypercalcemia, chemotherapy


  • All patients: CBC (leukocytosis, Hgb), BMP (AG, Ca, lytes, AKI), LFTs, lipase, lactate, UA

  • If risk factors: consider TSH, AM cortisol, troponin, β hCG, UDS

  • EKG to eval for ischemia and baseline QTc

  • Imaging:

    • If concern for obstruction (abd distention, decreased BMs) KUB, consider CT A/P
    • If concern for biliary pathology (RUQ pain, abnl LFTs) RUQ U/S
    • If vestibular/concern for CNS pathology CTH vs MRI brain


Address underlying cause and stop medications as appropriate

  • Many antiemetics prolong QTc, however in patients without underlying cardiac conduction abnormality, electrolyte abnormality, or organ failure the risk of QTc prolongation leading to significant arrhythmia is low.
  • Obtain screening EKG in patients with underlying heart disease, electrolyte abnormalities, organ failure or on other QTc prolonging meds (antiarrhythmics, antipsychotics, antibiotics)
  • 4-8 mg of IV Zofran is estimated to prolong QTc by ~6ms
  • Try to pick a medication that will address the underlying etiology of nausea
  • If patient does not respond to a medication in a certain class, try a medication from a different class (see below)
Med (by class) Typical Dose Side Effects Prolongs QT?
Serotonin antagonists
Ondansetron (Zofran) 4-8mg PO/IV q6h Constipation, headache, arrhythmia, serotonin syndrome Yes



1 mg PO BID, 2mg pre-chemo, OR 10mcg/kg IV pre-chemo ‘’ Yes
Dopamine Antagonists
Prochlorperazine (Compazine) 5-10 mg PO/IV q6h, 25 mg PR q6h EPS, less sedation than H-blockers (e.g. Phenergan) Yes



0.5-1 mg PO/IV q6h EPS, arrhythmia Yes
Zyprexa (Olanzapine) 5 -10mg PO qdaily EPS, constipation, anticholinergic Mild ^
Dopamine and Serotonin Antagonists
Metoclopramide (Reglan) 10 mg PO/IV q6h EPS/dystonia, arrhythmias, drowsiness/dizziness, diarrhea Yes
GABA-A Agonist



0.5-1mg PO/IV q6h PRN Sedation, delirium, amnesia, respiratory depression No
H1 Antagonists
Promethazine (Phenergan) 12.5 - 25mg PO /PR /IV q6h (avoid IV use if possible) Sedation, EPS (D2 antagonist also), arrhythmias, blurry vision Yes
Diphenhydramine (Benadryl) 25-50mg PO/IV q6h Sedation, delirium, urinary retention, ileus Yes



12.5-25mg PO q6h Sedation, dizziness, falls, blurry vision Yes
Scopolamine 1 mg patch q3day Dry mouth, blurry vision, drowsiness No
Dexamethasone 4-8mg PO/IV prior to chemo or XRT, typically use with other agents Hyperglycemia, fluid retention, delirium No
NK1 Antagonists
Aprepitant Given prior to/with chemo Fatigue, neutropenia No
CBD Agonists
Dronabinol 2.5-5mg BID Dizziness, increased appetite, Tachycardia, hypotension No