What is the recommended dose of fexofenadine (Allegra) for an End-Stage Renal Disease (ESRD) patient experiencing itching?

Fexofenadine Dosing for ESRD Patients with Itching

For ESRD patients with itching, start fexofenadine at 60 mg once daily (half the standard dose), though antihistamines have limited efficacy for uremic pruritus and gabapentin is a more effective alternative. 1, 2

Dose Adjustment in ESRD

• The FDA label explicitly recommends 60 mg once daily as the starting dose for adults with decreased renal function, compared to the standard 60 mg twice daily or 180 mg once daily for patients with normal renal function 2
• This dose reduction is supported by pharmacokinetic data showing a 63% decline in oral clearance of fexofenadine in ESRD patients 3
• For children 6-11 years with ESRD, reduce to 30 mg once daily (from the standard 30 mg twice daily) 2

Important Efficacy Considerations

Antihistamines generally have poor efficacy for uremic pruritus specifically, and you should strongly consider gabapentin instead. 1

• Gabapentin 100-300 mg administered after dialysis three times weekly demonstrates superior efficacy compared to antihistamines for uremic pruritus 1
• The British Journal of Dermatology guidelines note that cetirizine specifically lacks effectiveness for uremic pruritus in hemodialysis patients 1
• If using fexofenadine for uremic pruritus, set realistic expectations with the patient about limited anticipated benefit 1

Why Fexofenadine Over Other Antihistamines in ESRD

Fexofenadine is the preferred second-generation antihistamine in ESRD due to minimal sedating effects and favorable safety profile. 1, 4

• Avoid first-generation antihistamines (diphenhydramine, clemastine) in ESRD due to increased sedation risk, falls, and potential long-term cognitive effects 1
• Cetirizine and levocetirizine should be avoided entirely when creatinine clearance is <10 mL/min 1
• Loratadine requires cautious use with unclear dose adjustments in severe renal impairment 1
• Fexofenadine maintains a safety profile comparable to placebo even in renal impairment, with no clinically significant drug interactions 4

Administration Timing

• Administer fexofenadine after hemodialysis sessions to prevent premature drug removal and maintain therapeutic levels between dialysis sessions 5
• Take with water, not fruit juice, as grapefruit juice reduces fexofenadine bioavailability by 30% 3

Non-Pharmacologic Management (Do Not Overlook)

Before or alongside any antihistamine therapy, optimize these foundational interventions for uremic pruritus: 6

• Ensure adequate dialysis (target Kt/V around 1.6) 6
• Normalize calcium-phosphate balance and control parathyroid hormone 6
• Apply emollients liberally for xerosis (dry skin), which lowers the threshold for itch 6
• Consider high-flux hemodialysis over standard haemodialysis filtration 6

Common Pitfalls

• Do not use standard adult dosing (180 mg once daily) in ESRD—this leads to drug accumulation and potential toxicity 2, 3
• Do not expect robust antipruritic effects from fexofenadine for uremic pruritus; consider it a trial with early reassessment 1
• Do not combine with medications that inhibit P-glycoprotein or OATP transporters, as fexofenadine is a substrate for these transporters 3
• Do not overlook gabapentin as the more evidence-based pharmacologic option for uremic pruritus 1