Tamiflu Prophylaxis Dosing
For adults and adolescents ≥13 years, give oseltamivir 75 mg once daily for 10 days after exposure or up to 6 weeks during community outbreaks. 1
Adult and Adolescent Dosing (≥13 years)
- Standard prophylaxis dose is 75 mg once daily 2, 1, 3
- Duration: 10 days for post-exposure prophylaxis following close contact with an infected individual 1, 3
- Duration: Up to 6 weeks for seasonal/community outbreak prophylaxis 1, 3
- Immunocompromised patients may continue prophylaxis for up to 12 weeks 3
- Initiate within 48 hours of exposure for maximum effectiveness 1
Pediatric Dosing (≥1 year)
Weight-based once-daily dosing for children ≥1 year: 1, 3
- ≤15 kg: 30 mg once daily 1, 3
- >15-23 kg: 45 mg once daily 1, 3
- >23-40 kg: 60 mg once daily 1, 3
- >40 kg: 75 mg once daily 1, 3
- Duration: 10 days post-exposure or up to 6 weeks during community outbreaks 1, 3
Infants (3-11 months)
- Dose: 3 mg/kg once daily for 10 days if prophylaxis is deemed necessary 2, 1, 4
- Prophylaxis is NOT recommended for infants <3 months unless the situation is judged critical due to limited safety data 2, 1
Renal Impairment Adjustments
For creatinine clearance 10-30 mL/min, reduce the dose: 2, 1, 4
- Option 1: 30 mg once daily for 10 days 2, 1
- Option 2: 75 mg every other day for 10 days (total 5 doses) 2, 1
Critical Timing Considerations
- Post-exposure prophylaxis must be initiated within 48 hours of close contact with an infected individual for optimal effectiveness 1
- The duration of protection lasts only as long as oseltamivir is being taken 3
Common Prescribing Pitfalls to Avoid
- DO NOT confuse prophylaxis dosing (once daily) with treatment dosing (twice daily) - this is a frequent prescribing error 1
- Avoid oseltamivir if live attenuated influenza vaccine (LAIV) was given within the past 2 weeks, as it may interfere with vaccine efficacy 2, 1
- Do not give LAIV within 48 hours before starting oseltamivir 2
Administration Considerations
- Can be taken with or without food, though taking with food may improve gastrointestinal tolerability 2, 3
- Available as capsules (30 mg, 45 mg, 75 mg) or oral suspension (6 mg/mL when reconstituted) 2, 3
- Nausea and vomiting are common adverse effects (occurring in approximately 5-15% of patients), and are reduced when taken with food 2
Evidence Quality Note
The CDC and American Academy of Pediatrics guidelines consistently recommend these dosing regimens across multiple high-quality sources 2, 1, 4, 3. The FDA label confirms these recommendations 3. While older research studies 5, 6 demonstrated 70-92% protective efficacy for seasonal prophylaxis, more recent systematic reviews 7 show oseltamivir reduces symptomatic influenza by 55% in prophylaxis trials, though evidence for preventing complications remains limited.