Prophylactic Oseltamivir Dosing for a 2-Year-Old Weighing 25 Pounds
For a 2-year-old child weighing 25 pounds (11.3 kg), the prophylactic dose of oseltamivir is 30 mg once daily for 10 days. 1, 2
Weight-Based Dosing Algorithm
This child falls into the ≤15 kg (≤33 lb) weight category, which determines the appropriate dose 1, 3:
- Children weighing ≤15 kg (≤33 lb): 30 mg once daily for prophylaxis 1, 2, 3
- Children weighing >15-23 kg (33-51 lb): 45 mg once daily 1, 2
- Children weighing >23-40 kg (>51-88 lb): 60 mg once daily 1, 2
- Children weighing >40 kg (>88 lb): 75 mg once daily 1
Administration Details
Use 5 mL of the oral suspension (6 mg/mL concentration) once daily to deliver the 30 mg prophylactic dose 1, 2, 3:
- The oral suspension is the preferred formulation for young children who cannot swallow capsules 3
- Administer with food to improve gastrointestinal tolerability and reduce nausea/vomiting, which occurs in approximately 10% of patients 2
- The medication can be given without regard to meals, though tolerability is enhanced with food 3
Duration and Timing
Initiate prophylaxis within 48 hours of exposure to an infected individual 2:
- Post-exposure prophylaxis: Continue for 10 days following close contact with an infected person 1, 2, 3
- Seasonal/community outbreak prophylaxis: May continue for up to 6 weeks during a community outbreak 1, 3
- Protection lasts only as long as dosing is continued 3
Critical Distinction: Treatment vs. Prophylaxis Dosing
Do not confuse treatment dosing with prophylaxis dosing 4:
- Treatment dose for this weight category: 30 mg twice daily for 5 days 1, 3
- Prophylaxis dose for this weight category: 30 mg once daily for 10 days 1, 2, 3
The prophylaxis dose is half the daily treatment dose (once daily instead of twice daily) 1, 3
Special Considerations
- No renal dose adjustment is needed unless the child has significant renal impairment (creatinine clearance <60 mL/min) 2
- FDA approval: Oseltamivir is FDA-approved for prophylaxis in children ≥1 year of age 3
- For infants <1 year of age, prophylaxis is not recommended for those <3 months unless the situation is judged critical due to limited safety data 1