Tamiflu Dosing for 20-Month-Old Child Weighing 8.1 kg
For a 20-month-old child weighing 8.1 kg, administer oseltamivir 3 mg/kg per dose (approximately 24 mg), given twice daily for treatment or once daily for prophylaxis, using the oral suspension formulation (6 mg/mL concentration). 1
Weight-Based Dosing Calculation
The precise dose is calculated as 3 mg/kg × 8.1 kg = 24.3 mg per dose, which should be measured as approximately 4 mL of the 6 mg/mL oral suspension. 1
This dosing applies specifically to infants aged 3-11 months through children under 12 months of age, and the FDA has approved this 3 mg/kg dosing regimen for term infants in this age range. 1
Do NOT use the fixed-dose weight categories (≤15 kg = 30 mg) that apply only to children ≥12 months of age, as this would result in overdosing for this patient. 1
Treatment vs. Prophylaxis Regimens
For treatment of influenza: Administer 24 mg (4 mL) twice daily for 5 days, ideally initiated within 48 hours of symptom onset. 1, 2
For prophylaxis: Administer 24 mg (4 mL) once daily for 10 days following close contact with an infected individual. 1, 2
Administration Instructions
Use a calibrated oral dosing device that can accurately measure 4 mL volumes; for infants, ensure the dispensing device is appropriate for small volumes. 2
Administer with food to reduce gastrointestinal side effects such as nausea and vomiting, which occur in approximately 10% of patients. 3, 2
Critical Pitfalls to Avoid
Never round to the fixed 30 mg dose used for older children (≥12 months), as the 3 mg/kg calculation must be used for all infants under 1 year of age. 1
Do not use preterm infant dosing (1.0-1.5 mg/kg), which only applies to infants based on postmenstrual age considerations—this is a term infant scenario. 1
Ensure the full 5-day treatment course is completed even if symptoms improve earlier, as premature discontinuation may reduce efficacy. 3