Can Hydroxyzine Be Given Intravenously?
No, hydroxyzine should NOT be given intravenously in routine clinical practice due to significant safety concerns, despite recent research showing it has been used via this route in specific hospital settings.
Primary Safety Concerns
Tissue Necrosis Risk
- Intramuscular hydroxyzine is contraindicated based on documented cases of massive tissue necrosis, with one case report describing 100g of necrotic gluteal muscle requiring excision after IM injection, leaving permanent disability 1
- The mechanism involves arterial penetration causing thrombosis and subsequent muscle necrosis 1
- If IM administration carries this level of risk, IV administration poses theoretical concerns for vascular injury and extravasation complications
Cardiac Toxicity
- Hydroxyzine can prolong the QT interval and cause torsade de pointes, even at low doses (12.5 mg) 2
- This risk is particularly elevated in patients with bradycardia or complete atrioventricular block 2
- Concurrent use with phenothiazines, tricyclic antidepressants, or other QT-prolonging medications increases the likelihood of dysrhythmias and sudden death 3
Emerging Evidence for IV Use
Recent Hospital Experience
- A 2025 retrospective study documented intravenous hydroxyzine use as monotherapy for delirium in hospitalized patients, showing it was not inferior to haloperidol for time to improvement (7.0 vs 8.2 days) and superior for rate of improvement (23.9% vs 8.5%) 4
- This represents off-label use in a controlled hospital setting with monitoring capabilities 4
Guideline-Recommended Alternatives
For Acute Hypersensitivity Reactions
- Diphenhydramine is the preferred antihistamine, administered at 1-2 mg/kg or 25-50 mg parenterally (IM or IV) 5
- Ranitidine 1 mg/kg IV can be added, as the combination of H1 and H2 blockers is superior to H1 blockers alone 5
For Anaphylaxis Management
- Intramuscular epinephrine remains first-line treatment (0.01 mg/kg of 1:1000 solution, maximum 0.5 mg) 5
- IV fluids (10-20 mL/kg bolus) for hypotension 5
- Diphenhydramine (not hydroxyzine) for antihistamine effect 5
Clinical Bottom Line
Avoid IV hydroxyzine in routine practice. While recent research suggests it may be used safely in monitored hospital settings for specific indications like delirium 4, the lack of FDA approval for this route, documented tissue injury risk with parenteral administration 1, and cardiac toxicity concerns 2, 3 make this an inappropriate choice when safer alternatives exist. For allergic reactions, use diphenhydramine IV/IM instead 5. If hydroxyzine is considered for delirium in a hospital setting, this should only occur with continuous cardiac monitoring and awareness of QT prolongation risk 4, 2.