Tamiflu Dosing for a 5-Year-Old Weighing 22 kg
For a 5-year-old child weighing 22 kg, the recommended dose of oseltamivir (Tamiflu) is 45 mg twice daily for 5 days for treatment, or 45 mg once daily for 10 days for prophylaxis. 1, 2
Weight-Based Dosing Algorithm
This child falls into the >15 kg to 23 kg weight category, which determines the specific dose:
- Treatment dose: 45 mg (7.5 mL of oral suspension) twice daily for 5 days 1, 2
- Prophylaxis dose: 45 mg (7.5 mL of oral suspension) once daily for 10 days 1, 2
The weight-based dosing categories for children ≥1 year are structured as follows:
- ≤15 kg: 30 mg per dose 1
15-23 kg: 45 mg per dose (this patient) 1
23-40 kg: 60 mg per dose 1
40 kg: 75 mg per dose 1
Formulation Options
Oral suspension (6 mg/mL concentration): The 45 mg dose equals 7.5 mL of reconstituted suspension 1, 2
Capsule alternative: A 45 mg capsule can be used if the child can swallow it whole 2
If capsules need to be opened, the contents can be mixed with a sweetened liquid to mask the bitter taste 1
Administration Timing and Food
Initiate treatment within 48 hours of symptom onset for maximum effectiveness, with earlier initiation (within 12-24 hours) providing even greater benefit 3
Administer with food to improve gastrointestinal tolerability and reduce nausea and vomiting, which occur in approximately 10% of patients 1, 4, 3, 5
Dispensing Instructions
For a 5-day treatment course at 45 mg twice daily, dispense 2 bottles of oral suspension (each bottle contains 60 mL when reconstituted, providing 360 mg total per bottle) 2
For a 10-day prophylaxis course at 45 mg once daily, dispense 2 bottles of oral suspension 2
Critical Considerations
No renal dose adjustment is needed unless the child has significant renal impairment (creatinine clearance <60 mL/min), which would be unusual in a healthy 5-year-old 1, 2
Common pitfall: Using age-based rather than weight-based dosing can lead to underdosing or overdosing, as children of the same age vary significantly in weight 6, 7
Storage: Once reconstituted, the oral suspension is stable and should be shaken well before each use 2