Ibuprofen Dosing for a 45-Pound Child with High Fever
For this 45-pound (approximately 20 kg) child with a 104°F fever, administer 200 mg of ibuprofen (one capsule) as a single dose, which provides 10 mg/kg—the upper end of the effective therapeutic range.
Weight-Based Dosing Calculation
- A 45-pound child weighs approximately 20.4 kg 1
- The effective dose range for ibuprofen in children is 5-10 mg/kg per dose 1, 2
- For this child: 200 mg ÷ 20 kg = 10 mg/kg, which falls at the optimal upper therapeutic range 1
- Maximum reduction in temperature occurs 3-4 hours after administration 1
Dosing Frequency and Maximum Daily Dose
- Administer every 6-8 hours as needed for fever 3
- Maximum of 3-4 doses in 24 hours 3
- Total maximum daily dose should not exceed 30-40 mg/kg (600-800 mg for this child) 2
- This means no more than 4 doses of 200 mg in 24 hours 3
Clinical Effectiveness at This Dose
- The 10 mg/kg dose provides superior antipyretic effect compared to lower doses 1, 4
- Studies demonstrate that 10 mg/kg produces highly significant temperature reductions (p < 0.001) 4
- Ibuprofen at this dose is equally or more effective than acetaminophen and has a longer duration of action 1, 3
Critical Safety Considerations
- Short-term use of ibuprofen is safe in children over 3 months with body weight above 5-6 kg when special attention is given to hydration 2
- Ensure the child maintains adequate fluid intake during febrile illness 2
- The 200 mg capsule can be opened and mixed with a sweetened liquid if the child cannot swallow it whole 3
Common Pitfall to Avoid
- Do not exceed 4 doses (800 mg total) in 24 hours—studies show 8-11% of parents inadvertently exceed maximum recommended doses when using antipyretics 3
- Carefully record all dose times to prevent accidental overdosing 3
- Ibuprofen is safer in overdose than acetaminophen, but adherence to maximum dosing remains essential 1