What are the best medications for treating nausea in the Emergency Department (ED)?

Best Medications for Nausea in the Emergency Department

Dopamine receptor antagonists should be used as first-line treatment for nausea in the Emergency Department, with ondansetron as an effective second-line agent when first-line medications are insufficient or contraindicated. 1

First-Line Medications

• Dopamine receptor antagonists are recommended as first-line treatment for nausea in the ED, including:

  • Metoclopramide 10-20 mg IV/PO every 6-8 hours 1
  • Prochlorperazine 5-10 mg IV/PO every 6-8 hours 1
  • Haloperidol 0.5-2 mg IV/PO every 6-8 hours 1

• These medications are effective for undifferentiated nausea in the ED setting and have been shown to provide significant symptom relief 1, 2

• Metoclopramide has the added benefit of prokinetic effects, which can be helpful for constipation-related nausea 1

Second-Line Medications

• 5-HT3 receptor antagonists should be used when first-line medications are insufficient or contraindicated:

  • Ondansetron 4-8 mg IV/PO every 8 hours 1, 3
  • Granisetron 1 mg IV or PO daily 1
  • Palonosetron 0.25 mg IV (for more prolonged effect) 1

• Ondansetron is as effective as promethazine for nausea relief but causes less sedation, making it particularly useful in the ED setting 4

• Ondansetron is available in oral dissolving tablet (ODT) form, which is convenient for patients who cannot tolerate oral medications but do not require IV access 5

Administration Strategy

• For acute nausea in the ED:

  • Start with IV administration for faster onset of action 5
  • IV ondansetron has shown mean nausea score reductions of 4.4 points (on a 10-point scale) compared to 3.3 points with ODT formulations 5

• For persistent nausea:

  • Switch from as-needed dosing to scheduled around-the-clock administration 1
  • Consider combination therapy with medications from different classes (e.g., dopamine antagonist plus 5-HT3 antagonist) 1, 3

Special Considerations

• For anticipatory nausea:

  • Lorazepam 0.5-2 mg IV/PO can be added to the antiemetic regimen 3, 1

• For nausea associated with bowel obstruction or increased intracranial pressure:

  • Dexamethasone 2-8 mg IV/PO can be beneficial 3, 1

• For refractory nausea:

  • Droperidol 0.625-1.25 mg IV has shown efficacy but should be used with caution due to FDA black box warning regarding QT prolongation 6, 7
  • Consider adding a medication from a different class than what was initially used 1

Medication-Specific Considerations

Dopamine Antagonists

• Monitor for akathisia, which can develop up to 48 hours after administration 6
• Slow IV infusion rate can reduce incidence of akathisia 6
• Treat akathisia with IV diphenhydramine if it occurs 6

Promethazine

• More sedating than other antiemetics, which may be beneficial when sedation is desired 4
• Potential for vascular damage with IV administration; use with caution 6

Ondansetron

• Less sedating than promethazine, making it suitable for patients who need to remain alert 4
• Can cause constipation, which may worsen nausea if not addressed 1
• No risk of extrapyramidal symptoms (unlike dopamine antagonists) 6

Common Pitfalls and Caveats

• Avoid first-generation antihistamines like diphenhydramine as primary antiemetics as they can exacerbate hypotension and cause excessive sedation 3

• Consider the underlying cause of nausea when selecting an antiemetic:

  • For gastroparesis or functional dyspepsia, metoclopramide may be more effective due to its prokinetic properties 1
  • For vestibular causes, antihistamines may be more appropriate 1

• Intravenous fluid rehydration alone may be sufficient for many patients with mild to moderate nausea, as placebo response rates are high in clinical trials 2, 7

• Patients with severe nausea may benefit from combination therapy with medications from different classes rather than increasing the dose of a single agent 3, 1