Tamiflu Dosing for GFR 46 mL/min
For a patient with a GFR of 46 mL/min, use the standard adult dose of oseltamivir 75 mg twice daily for treatment or 75 mg once daily for prophylaxis—no dose adjustment is required. 1
Renal Function Thresholds for Dose Adjustment
The critical threshold for oseltamivir dose adjustment is a creatinine clearance (CrCl) of 30 mL/min, not 46 mL/min. 1, 2
Standard Dosing (CrCl ≥30 mL/min)
- Treatment regimen: 75 mg orally twice daily for 5 days 1
- Prophylaxis regimen: 75 mg orally once daily for 10 days after exposure 1
- Your patient with GFR 46 mL/min falls into this category and requires no adjustment 1, 2
Reduced Dosing (CrCl 10-30 mL/min)
Only when creatinine clearance drops to 10-30 mL/min should you reduce the dose: 1
- Treatment: 75 mg once daily for 5 days 1
- Prophylaxis: 30 mg once daily for 10 days OR 75 mg every other day for 10 days (5 total doses) 1
Severe Renal Impairment (CrCl <10 mL/min or Hemodialysis)
- Treatment: 30 mg per hemodialysis cycle 1, 2
- Prophylaxis: 30 mg every alternate hemodialysis cycle 1, 2
Key Clinical Considerations
Pharmacokinetic rationale: Oseltamivir carboxylate (the active metabolite) is eliminated >99% by renal excretion, with renal clearance exceeding glomerular filtration due to active tubular secretion via organic anion transporters. 2, 3 However, exposure remains therapeutic at GFR 46 mL/min without adjustment. 2
Administration details: Oseltamivir can be taken without regard to meals, though administration with food may reduce gastrointestinal side effects (primarily nausea and vomiting). 1, 2, 4, 5
Common pitfall: Do not confuse GFR with creatinine clearance thresholds—the 30 mL/min cutoff is well-established across multiple guidelines and the FDA label. 1, 2 Your patient at GFR 46 mL/min is well above this threshold.
Monitoring: While no specific monitoring is mandated for patients with mild-to-moderate renal impairment on standard doses, be alert for gastrointestinal adverse effects (nausea in 9.4%, abdominal pain in 9.1%, dizziness in 9.1% of patients). 6, 4, 5