What is the recommended dose of Tamiflu (oseltamivir) for an 8-year-old child with influenza?

Tamiflu Dosing for an 8-Year-Old Child

For an 8-year-old child with influenza, the dose of Tamiflu (oseltamivir) is determined by the child's current weight using weight-based dosing categories: 30 mg twice daily for ≤15 kg, 45 mg twice daily for >15-23 kg, 60 mg twice daily for >23-40 kg, or 75 mg twice daily for >40 kg, given for 5 days. 1, 2, 3, 4

Weight-Based Dosing Algorithm

The American Academy of Pediatrics and FDA recommend the following treatment doses for children aged 1-12 years 1, 3, 4:

• ≤15 kg (≤33 lb): 30 mg twice daily = 5 mL oral suspension twice daily 1, 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, 3

Most 8-year-old children typically weigh between 20-30 kg, which would place them in either the 45 mg or 60 mg dosing category—you must verify the child's current weight before prescribing. 3

Treatment Duration and Timing

• Treatment duration is 5 days regardless of weight category 1, 3, 4
• Initiate treatment within 48 hours of symptom onset for maximum effectiveness—oseltamivir reduces illness duration by approximately 1-1.5 days (26-36% reduction) when started early 1, 2
• Treatment can still be considered beyond 48 hours in hospitalized or high-risk patients, though efficacy data are more limited 5

Formulation Options

Oseltamivir is available as capsules (30 mg, 45 mg, 75 mg) or oral suspension (6 mg/mL when reconstituted). 1, 4

• The oral suspension is preferred for children who cannot swallow capsules 3, 4
• Capsules can be opened and contents mixed with liquid if needed 1
• If commercial suspension is unavailable, pharmacies can compound a suspension from capsules based on package insert instructions 1

Administration Recommendations

Administer oseltamivir with food to significantly reduce gastrointestinal side effects, particularly nausea and vomiting. 1, 2

• Nausea and vomiting occur in approximately 10-15% of patients but are mild and transient 1
• Taking with food reduces severity of these symptoms without affecting drug absorption 1
• Only approximately 1% of patients discontinue therapy due to gastrointestinal effects 1

Special Considerations and Pitfalls

Common dosing errors to avoid:

• Failing to verify current weight—using outdated weight measurements can lead to underdosing or overdosing 3
• Using age-based dosing instead of weight-based dosing—children aged 1-12 years require weight-based dosing, not age-based dosing 1, 4
• Incorrect volume measurements with oral suspension—ensure caregivers understand the correct mL volume for the prescribed dose 1

Renal impairment adjustments:

• No dose adjustment is needed for normal renal function 2
• For creatinine clearance 10-30 mL/min, reduce to 75 mg once daily (or weight-based equivalent once daily) instead of twice daily 1, 3

Prophylaxis Dosing (If Applicable)

If prescribing for post-exposure prophylaxis rather than treatment, use the same weight-based dose but once daily for 10 days instead of twice daily 1, 2, 3:

• Prophylaxis should be initiated within 48 hours following close contact with an infected individual 1
• Use the same weight-based dosing categories as treatment, but administered once daily 2, 3