Recommended Oseltamivir (Tamiflu) Prophylaxis Dosage After Influenza Exposure
For adults exposed to influenza, the recommended prophylactic dose of oseltamivir (Tamiflu) is 75 mg once daily for 10 days after exposure. 1
Adult Dosing
- Standard adult dose: 75 mg once daily 2, 1
- Duration: 10 days following close contact with an infected individual 1
- Timing: Should be initiated within 48 hours of exposure for maximum effectiveness 2, 3
- Renal impairment: For patients with creatinine clearance 10-30 mL/min, reduce dose to 30 mg once daily or 75 mg every other day 2, 3
Pediatric Dosing
Prophylactic dosing for children is weight-based:
| Weight | Prophylaxis Dosage | Volume of Oral Suspension (6 mg/mL) |
|---|---|---|
| ≤15 kg | 30 mg once daily | 5 mL |
| 15.1-23 kg | 45 mg once daily | 7.5 mL |
| 23.1-40 kg | 60 mg once daily | 10 mL |
| >40 kg | 75 mg once daily | 12.5 mL |
- Age requirement: Approved for prophylaxis in children ≥1 year of age 2, 1
- Duration: 10 days following exposure 2, 1
Special Populations
- Elderly patients: No dosage adjustment required based on age alone 2
- Immunocompromised patients: May continue prophylaxis for up to 12 weeks 1
- Institutional settings: Prophylaxis should continue until approximately 7-10 days after illness onset in the last patient during an outbreak 2
Important Considerations
Oseltamivir is not a substitute for influenza vaccination 1
Prophylaxis should be considered for:
Taking oseltamivir with food may improve gastrointestinal tolerability 3
The effectiveness of prophylaxis lasts only as long as the medication is taken 1
Common Pitfalls to Avoid
- Delayed initiation: Starting prophylaxis beyond 48 hours after exposure significantly reduces effectiveness 3
- Incorrect dosing: Using treatment doses (twice daily) instead of prophylaxis doses (once daily) 1
- Inadequate duration: Not completing the full 10-day course 1
- Relying solely on prophylaxis: Viewing oseltamivir as a replacement for vaccination rather than as an adjunct 1, 5
- Overuse: Indiscriminate use may lead to viral resistance 5
Oseltamivir prophylaxis should be used judiciously as part of a comprehensive approach to influenza prevention, with vaccination remaining the primary preventive strategy when possible.