Oseltamivir Dosing Guidelines

Introduction to Oseltamivir Dosing

The American Academy of Pediatrics recommends weight-based oseltamivir dosing for children ≥1 year, with doses ranging from 30 mg twice daily for ≤15 kg to 75 mg twice daily for >40 kg 1

The standard dose for adults and adolescents ≥13 years is 75 mg twice daily for 5 days for treatment of influenza, and 75 mg once daily for 10 days for prophylaxis 1

For children ≥1 year, weight-based dosing is preferred, with doses of 30 mg twice daily for ≤15 kg, 45 mg twice daily for >15-23 kg, 60 mg twice daily for >23-40 kg, and 75 mg twice daily for >40 kg 1, 2
For infants 9-11 months, the dose is 3.5 mg/kg per dose twice daily for treatment 3, 1
For infants 0-8 months, the dose is 3 mg/kg per dose twice daily for treatment 3, 1

Preterm infants require significantly lower doses due to immature renal function and risk of drug accumulation, with doses based on postmenstrual age (PMA) 4, 5, 1
For preterm infants <38 weeks PMA, the dose is 1.0 mg/kg per dose twice daily, for 38-40 weeks PMA the dose is 1.5 mg/kg per dose twice daily, and for >40 weeks PMA the dose is 3.0 mg/kg per dose twice daily 1

For patients with creatinine clearance 10-30 mL/min, the treatment dose is 30 mg once daily for 5 days, and the prophylaxis dose is 30 mg once daily or 75 mg every other day for 10 days 2, 3, 1

Oseltamivir is available as 30 mg, 45 mg, and 75 mg capsules and oral suspension (6 mg/mL when reconstituted) 3, 1
Administration with food is recommended to improve gastrointestinal tolerability 3, 1

The American Academy of Pediatrics recommends oseltamivir dosing for pediatric patients with normal or mildly impaired renal function (CrCl ≥30 mL/min) as follows: 30 mg twice daily (treatment) or once daily (prophylaxis) for children ≤15 kg, 45 mg twice daily (treatment) or once daily (prophylaxis) for children >15-23 kg, 60 mg twice daily (treatment) or once daily (prophylaxis) for children >23-40 kg, and 75 mg twice daily (treatment) or once daily (prophylaxis) for children >40 kg 6
For term infants 3-8 months, the Centers for Disease Control and Prevention recommends 3 mg/kg per dose once daily for prophylaxis 7, 6

The American Academy of Pediatrics recommends reducing the child's weight-based dose to once daily (instead of twice daily) for 5 days when creatinine clearance falls below 30 mL/min 6
For prophylaxis, the American Academy of Pediatrics recommends reducing to half the standard once-daily dose given once daily, or giving the full once-daily dose every other day for 10 days (5 total doses) 6

The American Academy of Pediatrics recommends giving oseltamivir with food to reduce gastrointestinal side effects, such as nausea and vomiting, which occur in approximately 10% of patients 6
The Centers for Disease Control and Prevention advises against confusing GFR with creatinine clearance, and against using standard term infant dosing for preterm infants, who have immature renal function and require significantly lower doses based on postmenstrual age 7, 6

The American Academy of Pediatrics recommends term infants aged 0-8 months require 3 mg/kg per dose twice daily for treatment of influenza 8, 9
For an 8kg infant, this calculates to 24 mg per dose, administered as 4 mL of the reconstituted oral suspension (6 mg/mL concentration) 8, 9
Treatment duration is 5 days for term infants 8, 9

The American Academy of Pediatrics states that the 3 mg/kg dosing applies ONLY to term infants—never use this dose for preterm infants 8, 9
Preterm infants have immature renal function and require substantially lower doses based on postmenstrual age (gestational age + chronological age) 8, 9
For preterm infants <38 weeks postmenstrual age: 1.0 mg/kg twice daily; 38-40 weeks: 1.5 mg/kg twice daily; >40 weeks: 3.0 mg/kg twice daily 8

The American Academy of Pediatrics advises to never use weight-based dosing intended for children ≥1 year (30 mg, 45 mg, 60 mg, 75 mg unit doses) in infants <1 year—these doses are too high 8, 9
Ensure the infant is term (≥37 weeks gestation at birth)—if preterm, use postmenstrual age-based dosing instead 8, 9

The American Academy of Pediatrics recommends for prophylaxis in infants 3-8 months, use 3 mg/kg once daily (instead of twice daily) for 10 days following exposure 8, 9
Prophylaxis is NOT recommended for infants <3 months unless the situation is judged critical, due to limited safety and efficacy data 8, 9