What is the recommended dose of Tamiflu (oseltamivir) for an adult male with normal renal function?

Tamiflu Dosing for Adult Males

For an adult male with normal renal function, the standard dose of Tamiflu (oseltamivir) is 75 mg orally twice daily for 5 days for treatment of influenza, or 75 mg once daily for 10 days for prophylaxis. 1, 2

Treatment Dosing (Active Influenza Infection)

Standard Regimen:

• 75 mg orally twice daily for 5 days 1, 2, 3
• Treatment should be initiated within 48 hours of symptom onset for maximum effectiveness 4
• Can be taken with or without food, though administration with meals may reduce gastrointestinal side effects (nausea and vomiting) 1, 2, 4, 3

Prophylaxis Dosing (Post-Exposure Prevention)

Standard Regimen:

• 75 mg orally once daily for 10 days following close contact with an infected individual 1, 2, 4
• Should be initiated within 48 hours of exposure 4
• For seasonal prophylaxis during community outbreaks, 75 mg once daily can be continued for up to 6 weeks 5

Renal Function Adjustments

Critical threshold for dose adjustment is creatinine clearance <30 mL/min (not GFR), as this is when oseltamivir carboxylate accumulation becomes clinically significant 1, 6, 3:

Moderate to Severe Renal Impairment (CrCl 10-30 mL/min):

• Treatment: 75 mg once daily (instead of twice daily) for 5 days 1, 6
• Prophylaxis: 30 mg once daily OR 75 mg every other day for 10 days (5 total doses) 1, 4, 6

End-Stage Renal Disease on Hemodialysis (CrCl <10 mL/min):

• Treatment: 30 mg per hemodialysis cycle 6, 3
• Prophylaxis: 30 mg every alternate hemodialysis cycle 6, 3

Normal or Mild Renal Impairment (CrCl ≥30 mL/min):

• No dose adjustment required 1, 6

Important Clinical Considerations

Age-Related Adjustments:

• No dose reduction is recommended based on age alone, even in elderly patients (≥65 years) 1
• Geriatric patients may have 25-35% higher exposure to oseltamivir carboxylate, but this does not require dose adjustment unless renal function is impaired 3

Hepatic Impairment:

• No dose adjustment is required for mild to moderate hepatic impairment 1, 3

Common Pitfalls to Avoid:

• Do not confuse GFR with creatinine clearance when determining the need for dose adjustment—the 30 mL/min threshold specifically refers to creatinine clearance 6
• Do not delay treatment waiting for laboratory confirmation of influenza in high-risk patients; empiric treatment should be initiated within 48 hours of symptom onset 4
• Do not withhold oseltamivir due to mild gastrointestinal symptoms, as these are typically transient and can be minimized by taking the medication with food 1, 2, 4

Formulation Options:

• Available as 30 mg, 45 mg, and 75 mg capsules 1, 2, 4
• Oral suspension available at 6 mg/mL concentration (12.5 mL = 75 mg dose) 1, 2, 4
• Capsules can be opened and mixed with sweetened liquid if swallowing is difficult 1, 2

Tolerability:

• Nausea and vomiting are the most common adverse effects, occurring in approximately 5-15% of patients 2, 4, 5, 7
• These gastrointestinal effects are typically mild, transient, and significantly reduced when taken with food 1, 5, 7
• The drug has minimal drug-drug interactions as it is not metabolized by cytochrome P450 enzymes 3, 8