What is the typical dose of Pepcid (famotidine) for itching?

Pepcid (Famotidine) Dosing for Itching

For pruritus management, famotidine 20 mg intramuscularly or orally is effective, though hydroxyzine 25-50 mg at bedtime is the preferred first-generation antihistamine for nighttime itching based on current dermatology guidelines. 1, 2

Evidence for Famotidine in Pruritus

Famotidine, an H2-receptor antagonist, has demonstrated efficacy in treating itching associated with acute urticaria. A controlled trial showed that famotidine 20 mg intramuscularly significantly reduced pruritus intensity, urticaria severity, and body surface area involvement without causing sedation, with comparable efficacy to diphenhydramine 50 mg. 3 This non-sedating profile makes it particularly advantageous for daytime use.

Clinical Context and Positioning

While famotidine shows promise for pruritus, current guidelines prioritize H1-antihistamines as the primary treatment for itching. 1 The American Academy of Dermatology recommends:

• Non-sedating second-generation H1-antihistamines (loratadine, fexofenadine) for daytime pruritus management 1, 4
• First-generation H1-antihistamines like hydroxyzine 25-50 mg at bedtime for nighttime itching 1, 2

When to Consider H2-Antagonists

H2-antihistamines like famotidine should be considered as adjunctive therapy when H1-antihistamines provide inadequate response. 1 The British Association of Dermatologists suggests adding H2-antihistamines when increasing H1-antihistamine doses or switching agents fails to control symptoms. 1

For combination therapy in moderate to severe pruritus, famotidine 20 mg twice daily can be added to daytime non-sedating H1-antihistamines and nighttime hydroxyzine. 2, 4

Specific Dosing Recommendations

Based on available evidence:

• Acute urticaria with pruritus: Famotidine 20 mg intramuscularly or orally as a single dose 3
• Chronic pruritus requiring H2-blockade: Famotidine 20 mg orally twice daily (extrapolated from standard H2-antagonist dosing for gastric acid suppression) 5, 6

Important Caveats

Famotidine's primary FDA-approved indication is gastric acid suppression, not pruritus. 5, 6 Its use for itching represents off-label prescribing based on limited evidence. The single published trial for urticaria-associated pruritus involved only 25 patients. 3

In cardiovascular patients on dual antiplatelet therapy (aspirin plus clopidogrel), famotidine 20 mg twice daily is specifically recommended over proton pump inhibitors because H2-blockers do not interfere with clopidogrel's antiplatelet activity. 7 This makes famotidine particularly suitable for pruritus management in this population.

Practical Algorithm

1. First-line daytime: Non-sedating H1-antihistamine (loratadine 10 mg daily or fexofenadine 180 mg daily) 4
2. First-line nighttime: Hydroxyzine 25-50 mg at bedtime 1, 2
3. Inadequate response: Increase H1-antihistamine dose or add famotidine 20 mg twice daily 1, 2
4. Acute urticaria with severe pruritus: Consider famotidine 20 mg IM for rapid, non-sedating relief 3

Dose adjustments are necessary in renal impairment, as famotidine is 70% renally eliminated with a half-life of 2.8 hours that prolongs nonlinearly with decreased kidney function. 5