What is the prophylactic dose of Tamiflu (oseltamivir) for influenza prevention?

Tamiflu Prophylactic Dose

For adults and adolescents ≥13 years, the prophylactic dose of Tamiflu (oseltamivir) is 75 mg orally once daily, initiated within 48 hours of exposure and continued for at least 10 days for post-exposure prophylaxis or up to 6 weeks during community outbreaks. 1

Adult and Adolescent Prophylaxis (≥13 years)

• Standard dose: 75 mg once daily 2, 3, 1
• Duration varies by indication:
  • Post-exposure prophylaxis: 10 days following close contact with infected individual 1
  • Seasonal/community outbreak prophylaxis: Up to 6 weeks 1
  • Immunocompromised patients: May extend up to 12 weeks 1
• Protection lasts only as long as oseltamivir is being taken 1

Pediatric Prophylaxis (1-12 years)

Weight-based dosing once daily for 10 days post-exposure: 1

• ≤15 kg: 30 mg once daily 2, 1

• 15-23 kg: 45 mg once daily 2, 1

• 23-40 kg: 60 mg once daily 2, 1

• 40 kg: 75 mg once daily 2, 1

Note: Prophylaxis is not FDA-approved for infants <1 year of age 1

Renal Impairment Adjustments

For patients with creatinine clearance 10-30 mL/min: 2, 3

• 30 mg once daily for 10 days, OR
• 75 mg every other day for 10 days (5 total doses) 2

Oseltamivir is not recommended for end-stage renal disease patients not on dialysis 1

Critical Administration Points

• Initiate within 48 hours of exposure for post-exposure prophylaxis 1
• Can be taken with or without food, though taking with meals improves gastrointestinal tolerability 2, 3, 1
• Available as capsules (30 mg, 45 mg, 75 mg) or oral suspension (6 mg/mL when reconstituted) 2, 3

Evidence Quality Notes

The protective efficacy of oseltamivir prophylaxis is well-established at 74% overall and 82% in high-prevalence settings when given as 75 mg once daily for 6 weeks 4. A shorter 3-day regimen showed 93% protective efficacy in hospital ward settings when index cases were immediately isolated, though this requires immediate separation of contacts from infected patients 5. The standard 7-10 day post-exposure regimen remains the FDA-approved and guideline-recommended approach 1.

Common Pitfalls

• Nausea occurs in approximately 12% of patients on prophylaxis, compared to 7% on placebo 4
• Avoid live attenuated influenza vaccine (LAIV) within 48 hours before oseltamivir use, and do not use oseltamivir for 14 days after LAIV vaccination 2
• Oseltamivir is not a substitute for annual influenza vaccination 1