IV Haloperidol Dosing for Intractable Vomiting
For intractable vomiting in adults, administer haloperidol 0.5-2 mg IV every 6-8 hours as needed, with most patients responding to 1.5 mg per 24 hours. 1
Recommended Dosing Strategy
Start with 0.5-1 mg IV as the initial dose, then reassess at 48 hours for response. 1, 2 The evidence supports this conservative approach:
- The median effective dose across palliative care studies is 1.5 mg per 24 hours (range 0.5-5 mg/24 hours), administered either as divided doses or continuous infusion 3
- Low-dose haloperidol (≤0.5 mg) demonstrates similar efficacy to higher doses with better tolerability profiles 2
- Doses can be repeated every 6-8 hours based on the dosing table from World Journal of Emergency Surgery guidelines 1
Expected Clinical Response
Complete resolution of nausea and vomiting occurs in 79% of patients within 48 hours of initiating haloperidol therapy. 3 Key response patterns include:
- Greater benefit for nausea resolution compared to vomiting 3
- Haloperidol 1 mg IV is non-inferior to ondansetron 4 mg IV for established nausea/vomiting, with 58% complete response rates 4
- The timing of administration (induction vs. end of procedure) does not affect antiemetic efficacy 5
Route Considerations
IV or subcutaneous routes are equally effective for antiemetic dosing. 1 Important route-specific considerations:
- Topical/transdermal haloperidol (ABH gel) is not significantly absorbed and should not be used 6
- Oral and parenteral routes achieve comparable clinical effects at equivalent doses 1, 3
Common Adverse Effects
Expect mild-to-moderate side effects in 26% of patients by day seven, most commonly: 3
- Constipation (40% of adverse events)
- Dry mouth (21% of adverse events)
- Sedation occurs in 25% of patients receiving haloperidol vs. 2% with ondansetron 4
- QT prolongation risk exists but is generally manageable at antiemetic doses 1
Critical Safety Monitoring
Monitor for extrapyramidal symptoms and QT interval changes, particularly with repeated dosing. 1 Essential precautions include:
- Baseline and follow-up ECG if using doses >2 mg or in patients with cardiac risk factors 1
- Avoid in patients already on QT-prolonging medications without cardiology consultation 1
- No dose adjustment needed for elderly patients, though they may be more sensitive to sedation 2
When to Escalate or Add Agents
If nausea/vomiting persists after 48 hours at 2 mg every 6-8 hours, add a second-line agent rather than increasing haloperidol further. 1 Recommended additions:
- Ondansetron (5-HT3 antagonist) as the preferred second agent 1
- Consider octreotide specifically for malignant bowel obstruction 1
- Dexamethasone 2-8 mg IV for bowel obstruction or increased intracranial pressure 1
Clinical Pitfall to Avoid
Do not exceed 5 mg per 24 hours for antiemetic purposes without specialist consultation, as higher doses increase adverse effects without improving efficacy. 3 The evidence shows diminishing returns and increased harm beyond this threshold, particularly for sedation and extrapyramidal effects.