IV Medication for Intense Pruritus
For acute, severe pruritus requiring IV treatment, give intravenous cetirizine 10 mg as first-line therapy, which is superior to diphenhydramine with less sedation, fewer adverse effects, and shorter treatment center time. 1
Primary IV Options
First-Line: IV Cetirizine
- Administer cetirizine 10 mg IV as the preferred agent for acute severe pruritus requiring parenteral therapy 1
- This second-generation antihistamine demonstrates equivalent efficacy to diphenhydramine for pruritus relief but with significantly better safety profile 1
- Patients experience less sedation (sedation score change 0.1 vs 0.5), fewer adverse events (3.9% vs 13.3%), and shorter treatment center stays (1.7 vs 2.1 hours) compared to diphenhydramine 1
- Lower rates of return visits (5.5% vs 14.1%) make this the most practical IV antihistamine option 1
Alternative: IV Diphenhydramine
- Give diphenhydramine 50 mg IV if cetirizine is unavailable 1
- Expect significant sedation and anticholinergic effects in approximately 13% of patients 1
- First-generation antihistamines like diphenhydramine are most useful when sedation is actually desired (nighttime dosing) 2, 3
Context-Specific IV Therapies
For Opioid-Induced Pruritus
- Administer ondansetron IV as an effective alternative when opioid cessation is impossible 2, 3
- Consider IV droperidol or IV methylnaltrexone as additional options 2, 3
- Naltrexone remains first-choice but is typically given orally rather than IV 2, 3
For Hepatic/Cholestatic Pruritus
- Consider propofol infusion for severe refractory cases as a fifth-line agent 2
- This is reserved for extreme cases unresponsive to oral rifampicin, cholestyramine, and sertraline 2
For Postoperative Pruritus
- Give diclofenac 100 mg rectally (not IV, but important alternative to IV antihistamines) 2
Critical Pitfalls to Avoid
Do NOT add IV corticosteroids to antihistamine therapy for uncomplicated pruritus. 4 A randomized controlled trial demonstrated that adding IV dexamethasone to chlorpheniramine provided no additional benefit for pruritus relief at 60 minutes, and oral corticosteroid continuation was associated with persistent urticaria activity at follow-up 4. Corticosteroids should be reserved only for severe systemic reactions or specific underlying conditions (lymphoma, paraneoplastic pruritus), not routine pruritus management 2.
When IV Therapy Is Insufficient
If IV antihistamines fail to control severe pruritus:
- Transition to oral gabapentin (900-3600 mg daily) or pregabalin (25-150 mg daily) as second-line agents 2, 3
- Consider oral doxepin 10 mg twice daily for antihistamine-resistant cases, particularly in uremic pruritus where it achieves 87.5% improvement rates 3
- Evaluate for specific underlying causes requiring targeted therapy (hepatic: rifampicin; uremic: optimize dialysis; neuropathic: specialist referral) 2, 3
Important Limitations
Antihistamines (IV or oral) have limited efficacy in non-histamine-mediated pruritus such as atopic dermatitis, psoriasis, and many chronic pruritic conditions 5, 6, 7. In these cases, histamine receptors do not play a decisive pathogenic role, and alternative mechanisms must be targeted 6, 7. The H₁ receptor antagonists work best for urticaria and allergic pruritus where histamine is the primary mediator 5, 7.