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

Tamiflu (Oseltamivir) Dosing for Pediatric Patients

The recommended dosage of Tamiflu (oseltamivir) for pediatric patients varies by weight and age, with children ≥12 months requiring weight-based dosing (≤15 kg: 30 mg twice daily; 15-23 kg: 45 mg twice daily; 23-40 kg: 60 mg twice daily; >40 kg: 75 mg twice daily), and infants <12 months requiring 3 mg/kg twice daily for treatment of influenza. 1, 2

Weight-Based Dosing for Children ≥12 Months

For children 12 months and older, weight-based dosing is preferred:

• ≤15 kg (≤33 lb): 30 mg twice daily for 5 days 3, 1

• 15 to 23 kg (33-51 lb): 45 mg twice daily for 5 days 3, 1

• 23 to 40 kg (51-88 lb): 60 mg twice daily for 5 days 3, 1

• 40 kg (>88 lb): 75 mg twice daily for 5 days 3, 1

Infant Dosing (<12 Months)

For infants younger than 12 months:

• 3-12 months: 3 mg/kg per dose twice daily for 5 days 3
• 0-3 months: 3 mg/kg per dose twice daily for 5 days (use only if situation is judged critical) 3

Preterm Infant Considerations

Preterm infants require lower weight-based dosing due to immature renal function 1:

• <38 weeks postmenstrual age: 1.0 mg/kg twice daily 1
• 38-40 weeks postmenstrual age: 1.5 mg/kg twice daily 1

• 40 weeks postmenstrual age: 3.0 mg/kg twice daily 1

Formulation and Administration

• Oseltamivir is available as capsules (30 mg, 45 mg, and 75 mg) and as a powder for oral suspension (6 mg/mL when reconstituted) 1, 2
• For the 6 mg/mL suspension, dosing volumes are:
  • 30 mg dose = 5 mL
  • 45 mg dose = 7.5 mL
  • 60 mg dose = 10 mL
  • 75 mg dose = 12.5 mL 3, 1
• Administration can be with or without food, though taking with food may improve gastrointestinal tolerability 1, 2

Treatment Duration and Timing

• Treatment duration is 5 days for all pediatric age groups 3, 1
• Treatment should be initiated within 48 hours of symptom onset for maximum effectiveness 1, 4
• Recent research confirms that oseltamivir significantly reduces the intensity of influenza symptoms and reduces hospitalization days in pediatric patients 5

Special Considerations

• For patients with renal insufficiency (creatinine clearance 10-30 mL/min), dose adjustment is required 1
• Common adverse events include nausea, vomiting, and diarrhea, particularly in children 1, 6
• When using oseltamivir in very young infants, especially those <3 months, benefits should be carefully weighed against risks due to limited data in this age group 3

Clinical Pearls

• Weight-based dosing is preferred over age-based dosing when weight is known 1, 4
• For infants who cannot accurately receive the commercially manufactured suspension, an appropriate measuring device such as a 3-mL or 5-mL oral syringe should be used 3
• Children eliminate the active metabolite faster than adolescents and adults, which is why weight-based dosing is crucial for appropriate therapeutic levels 7