Does a patient on hemodialysis (hemodialysis) three times weekly with impaired renal function (renal impairment) and positive for influenza (flu) require a dose adjustment of Tamiflu (oseltamivir), or can they receive 75 mg twice daily?

Oseltamivir Dosing for Hemodialysis Patients with Influenza

A patient on hemodialysis three times weekly with influenza requires dose adjustment and cannot receive the standard 75 mg twice daily regimen—the correct treatment dose is 30 mg administered immediately after each hemodialysis session for a total of 5 days (not to exceed 5 days of treatment). 1, 2, 3

Critical Dosing Error to Avoid

The standard 75 mg twice daily dosing used in patients with normal renal function is contraindicated in hemodialysis patients. 2 This would result in dangerous drug accumulation, as oseltamivir carboxylate (the active metabolite) is eliminated almost entirely by renal excretion and has markedly reduced clearance in end-stage renal disease. 2, 3

Correct Treatment Regimen for Hemodialysis Patients

For influenza treatment:

• Administer 30 mg immediately upon diagnosis (do not wait for the next dialysis session if diagnosis occurs between sessions). 3
• Then give 30 mg after each hemodialysis session for the remainder of the 5-day treatment course. 1, 2, 3
• Total treatment duration should not exceed 5 days. 2

Rationale for this dosing:

• During hemodialysis, oseltamivir carboxylate clearance increases dramatically to 7.43 L/min, compared to only 0.19 L/min between dialysis sessions. 3
• The 30 mg post-dialysis dose produces trough concentrations above the median therapeutic level achieved with 75 mg twice daily in patients with normal renal function, while keeping peak concentrations below safety thresholds. 3
• This regimen achieves median simulated AUC₄₈ of 23,200 ng·h/mL and Cmin of 221 ng/mL, which are therapeutically adequate. 2

Prophylaxis Dosing (If Applicable)

If prophylaxis rather than treatment is needed:

• Administer 30 mg after every other hemodialysis session (e.g., if dialyzing Monday/Wednesday/Friday, give doses after Monday and Friday sessions only). 1, 2, 3
• Continue for the recommended prophylaxis duration (typically 10 days post-exposure). 2

Key Clinical Considerations

Timing of first dose:

• If influenza is diagnosed between dialysis sessions, give 30 mg immediately—do not delay treatment waiting for the next dialysis session. 3
• Adding a single 30 mg dose during the 12 hours before the next scheduled dialysis raises therapeutic concentrations quickly without safety concerns. 3

Why dose adjustment is mandatory:

• Oseltamivir carboxylate exposure is inversely proportional to renal function. 2
• In ESRD patients, hemodialysis contributes minimally to overall drug clearance between sessions. 2
• Without dose reduction, drug accumulation leads to exposures far exceeding safe levels. 3

Alternative consideration:

• Zanamivir (inhaled) requires no dose adjustment in any degree of renal impairment, including ESRD, making it an alternative option if oseltamivir is contraindicated or not tolerated. 1
• Zanamivir dosing remains 10 mg (two inhalations) twice daily for treatment regardless of renal function. 1

Common Pitfall

Do not confuse creatinine clearance thresholds: The critical threshold for oseltamivir dose reduction is CrCl <30 mL/min, not other values. 1 Hemodialysis patients have CrCl ≤10 mL/min and require the most aggressive dose reduction. 2