Oseltamivir Dosing Recommendations for Influenza Treatment and Prophylaxis
For influenza treatment and prophylaxis, oseltamivir should be dosed according to age and weight, with 75 mg twice daily for 5 days for treatment in adults and weight-based dosing in children, while prophylaxis requires once-daily dosing for 10 days. 1
Adult Dosing
Pediatric Dosing (by weight for children ≥12 months)
| Body Weight | Treatment (5 days) | Prophylaxis (10 days) |
|---|---|---|
| ≤15 kg (≤33 lb) | 30 mg twice daily | 30 mg once daily |
| >15-23 kg (33-51 lb) | 45 mg twice daily | 45 mg once daily |
| >23-40 kg (51-88 lb) | 60 mg twice daily | 60 mg once daily |
| >40 kg (>88 lb) | 75 mg twice daily | 75 mg once daily |
Infant Dosing
- 9-11 months: 3.5 mg/kg twice daily for treatment; 3.5 mg/kg once daily for prophylaxis 1
- 3-8 months: 3 mg/kg twice daily for treatment; 3 mg/kg once daily for prophylaxis 1
- 0-3 months: 3 mg/kg twice daily for treatment; prophylaxis not recommended unless situation judged critical 1
Preterm Infant Dosing (by postmenstrual age)
- <38 weeks: 1.0 mg/kg twice daily 1
- 38-40 weeks: 1.5 mg/kg twice daily 1
- >40 weeks: 3.0 mg/kg twice daily 1
Special Considerations
Renal Impairment
For patients with creatinine clearance 10-30 mL/min:
- Treatment: 75 mg once daily for 5 days 1
- Prophylaxis: 30 mg once daily or 75 mg once every other day for 10 days 1
Administration
- Can be administered without regard to meals, though taking with food may improve gastrointestinal tolerability 1, 2
- Available as capsules (30 mg, 45 mg, 75 mg) and oral suspension (6 mg/mL) 1
- If commercial suspension is unavailable, capsules may be opened and mixed with sweetened liquid 1
Treatment Duration
- Standard treatment duration is 5 days for all age groups 1, 3
- Prophylaxis duration is 10 days after exposure 1
Clinical Pearls
- Early initiation of treatment (within 48 hours of symptom onset) maximizes efficacy 4, 2
- Treatment within 12 hours of symptom onset can reduce illness duration by an additional 74.6 hours compared to starting at 48 hours 2
- For extremely preterm infants (<28 weeks), consult a pediatric infectious disease specialist 1
- Weight-based dosing is preferred for infants; age-based dosing should only be used when weight is unknown 1
- Oseltamivir reduces the incidence of secondary complications such as otitis media, bronchitis, pneumonia, and sinusitis 4, 2
Remember that early initiation of therapy is crucial for maximizing the clinical benefit of oseltamivir in influenza treatment, with significant reductions in duration and severity of illness when started promptly after symptom onset.