What can I order for nausea that won’t cause hypotension when Zofran (ondansetron) isn’t an option?

Antiemetic Options When Ondansetron is Contraindicated

For nausea without risk of hypotension, use prochlorperazine 5-10 mg every 6 hours or haloperidol 0.5-1 mg every 6-8 hours as first-line alternatives to ondansetron. 1

Dopamine Antagonists (Preferred Alternatives)

These agents work centrally without significant cardiovascular effects:

• Prochlorperazine: 5-10 mg orally or IV every 6 hours as needed 1

  • Can be given around-the-clock if nausea persists beyond initial treatment 1
  • Well-studied in multiple clinical contexts including chemotherapy-induced nausea 1

• Haloperidol: 0.5-1 mg orally every 6-8 hours 1

  • Particularly effective for opioid-induced nausea 1
  • Minimal cardiovascular effects at these doses 1

• Metoclopramide: 10-20 mg orally or IV every 6-8 hours 1

  • Has prokinetic properties in addition to antiemetic effects 1
  • Useful when gastroparesis contributes to nausea 1
  • Caution: Can cause extrapyramidal side effects with prolonged use 1

Alternative 5-HT3 Antagonists

If the issue with ondansetron is availability rather than class contraindication:

• Granisetron: 1 mg orally twice daily or 34.3 mg transdermal patch weekly 1
  • Similar efficacy to ondansetron 1
  • Transdermal formulation may be advantageous for persistent symptoms 1

Anticholinergic Agents

For specific contexts (motion sickness, vestibular causes):

• Scopolamine: 1.5 mg transdermal patch every 3 days 1

  • Particularly effective for postoperative nausea 1
  • Minimal hemodynamic effects 1

• Meclizine: 12.5-25 mg three times daily 1

Combination Therapy Approach

When monotherapy fails, add dexamethasone 4-8 mg orally twice daily for maximum 4 days rather than escalating a single agent. 1

• Combination regimens are significantly more effective than single agents 1
• Dexamethasone has no hypotensive effects and enhances efficacy of dopamine antagonists 1

Neurokinin-1 Receptor Antagonists

For refractory nausea:

• Aprepitant: 80-125 mg daily 1
  • Effective in up to one-third of patients with troublesome nausea 1
  • No cardiovascular effects 1
  • Limitation: Cost may be prohibitive 1

Critical Clinical Considerations

Always rule out correctable causes before escalating antiemetic therapy:

• Constipation (especially with opioid use) 1
• Hypercalcemia 1
• CNS pathology 1
• Medication interactions 1

For persistent nausea despite as-needed dosing, switch to scheduled around-the-clock administration for 1 week rather than continuing PRN dosing. 1, 2

Agents to Avoid in Hypotension-Risk Patients

• Promethazine: Can cause sedation and orthostatic hypotension 1
• Chlorpromazine: Significant alpha-blockade causing hypotension 1
• Droperidol: Can cause hypotension, though less studied in this context 1

Practical Algorithm

1. First-line: Prochlorperazine 10 mg every 6 hours OR haloperidol 0.5-1 mg every 6-8 hours 1
2. If inadequate response after 24 hours: Switch to scheduled dosing (not PRN) 1, 2
3. If still inadequate after 48 hours: Add dexamethasone 8 mg twice daily 1
4. If refractory after 1 week: Consider metoclopramide 10-20 mg three times daily OR aprepitant 80 mg daily 1