What is the recommended dose of Tamiflu (oseltamivir) for pediatric patients?

Tamiflu (Oseltamivir) Pediatric Dosing

For pediatric patients, oseltamivir dosing is weight-based for children ≥12 months and age-based for infants, with treatment requiring twice-daily dosing for 5 days and prophylaxis requiring once-daily dosing for 10 days. 1, 2

Treatment Dosing (5 days, twice daily)

Children ≥12 months to 12 years (Weight-Based)

• ≤15 kg (≤33 lb): 30 mg twice daily = 5 mL oral suspension twice daily 1, 2, 3
• >15-23 kg (>33-51 lb): 45 mg twice daily = 7.5 mL oral suspension twice daily 1, 2, 3
• >23-40 kg (>51-88 lb): 60 mg twice daily = 10 mL oral suspension twice daily 1, 2, 3
• >40 kg (>88 lb): 75 mg twice daily = 12.5 mL oral suspension twice daily 1, 2, 3

Adolescents ≥13 years

• 75 mg twice daily for 5 days (same as adult dosing) 1, 2, 3

Infants <12 months (Age-Based, mg/kg dosing)

• 9-11 months: 3.5 mg/kg per dose twice daily for 5 days 1, 2
• Term infants 0-8 months: 3.0 mg/kg per dose twice daily for 5 days 1, 2

Preterm Infants (Postmenstrual Age-Based)

Preterm infants require substantially lower doses due to immature renal function: 1, 2

• <38 weeks postmenstrual age: 1.0 mg/kg twice daily for 5 days 1, 2
• 38-40 weeks postmenstrual age: 1.5 mg/kg twice daily for 5 days 1, 2
• >40 weeks postmenstrual age: 3.0 mg/kg twice daily for 5 days 1, 2

Prophylaxis Dosing (10 days, once daily)

Children ≥12 months to 12 years (Weight-Based)

Use the same weight-based doses as treatment, but once daily instead of twice daily for 10 days: 1, 2

• ≤15 kg: 30 mg once daily = 5 mL once daily 1, 2
• >15-23 kg: 45 mg once daily = 7.5 mL once daily 1, 2
• >23-40 kg: 60 mg once daily = 10 mL once daily 1, 2
• >40 kg: 75 mg once daily = 12.5 mL once daily 1, 2

Adolescents ≥13 years

• 75 mg once daily for 10 days 1, 2

Infants 3-11 months

• 3.0 mg/kg once daily for 10 days 1, 2

Infants <3 months

• Prophylaxis is NOT recommended for infants <3 months unless the situation is judged critical due to limited safety data 1

Renal Impairment Adjustments

For pediatric patients with creatinine clearance 10-30 mL/min: 1, 2

• Treatment: 75 mg once daily (instead of twice daily) for 5 days 1
• Prophylaxis: 30 mg once daily for 10 days OR 75 mg every other day for 10 days (5 total doses) 1, 2

Critical Timing Considerations

Treatment must be initiated within 48 hours of symptom onset for maximum effectiveness, though treatment should not be withheld in high-risk or hospitalized patients even beyond 48 hours. 1, 2

Prophylaxis should be initiated within 48 hours following close contact with an infected individual. 1

Formulation and Administration

Available Formulations

• Capsules: 30 mg, 45 mg, 75 mg 1, 2, 3
• Oral suspension: 6 mg/mL when reconstituted (preferred for patients who cannot swallow capsules) 1, 2, 3

Administration Tips

• Oseltamivir can be taken with or without food, but taking with food significantly reduces nausea and vomiting, which occur in approximately 10-15% of patients. 1, 4
• If commercial suspension is unavailable, capsules can be opened and contents mixed with liquid or compounded by pharmacies to achieve 6 mg/mL concentration. 1

Common Pitfalls to Avoid

• Do not use adult dosing in children—pediatric patients eliminate oseltamivir faster than adults and require weight-based or age-based dosing, not simply reduced adult doses. 5
• Do not forget to adjust for postmenstrual age in preterm infants—using term infant dosing in preterm infants can cause toxicity due to immature renal function. 1
• Do not withhold treatment while waiting for laboratory confirmation in high-risk patients—rapid antigen tests have poor sensitivity, and treatment should be initiated empirically. 2
• Do not administer live attenuated influenza vaccine (LAIV) within 48 hours before oseltamivir, and do not use oseltamivir for 14 days after LAIV vaccination. 1, 2