Appropriate Ibuprofen Dosing for a 12-Year-Old Weighing 44 kg
The appropriate dose of Motrin (ibuprofen) for a 12-year-old boy weighing 44 kg is 440 mg per dose, given every 6-8 hours as needed, with a maximum of 3 doses (1320 mg) in 24 hours.
Dosing Calculation and Rationale
The recommended weight-based dosing for ibuprofen in children is:
- 10 mg/kg per dose 1
- For this 44 kg child: 10 mg/kg × 44 kg = 440 mg per dose
Administration Guidelines
- Frequency: Every 6-8 hours as needed
- Maximum daily dose: 1200-1500 mg per day 1
- Administration: Should be taken with food to minimize gastrointestinal side effects 1
- Available forms: Can be administered as tablets, capsules, or liquid formulation
Evidence-Based Support
The European Society for Paediatric Anaesthesiology recommends ibuprofen at 10 mg/kg every 8 hours for children 1. This dosing is supported by pharmacokinetic studies showing that:
- The relationship between dose and response is linear over the range of 5-10 mg/kg 2
- Clinical trials have established the effective dose range to be 7.5-10 mg/kg 2
- Maximum analgesic and antipyretic effects occur 3-4 hours after administration 2
Safety Considerations
Ibuprofen is generally well-tolerated in children with a safety profile comparable to acetaminophen at recommended doses 1, 3. Important safety points include:
- Low risk of serious gastrointestinal events at OTC doses 3
- Short plasma half-life of elimination contributes to low toxic potential 3
- Better tolerated by children than adults 2
Common Pitfalls to Avoid
- Underdosing: Using less than 10 mg/kg may result in inadequate pain or fever control
- Exceeding maximum daily dose: Should not exceed 1320 mg in 24 hours for this child
- Administration on empty stomach: Should be given with food to minimize GI irritation 1
- Fixed adult dosing: Using standard adult doses (e.g., 200 mg) would be insufficient for this child's weight
Practical Dosing Approach
For a 44 kg child, the 440 mg dose can be achieved using:
- Two 200 mg tablets plus one 40 mg chewable tablet
- One 400 mg tablet plus one 40 mg chewable tablet
- Liquid formulation (100 mg/5 mL): 22 mL per dose
Regular dosing provides better symptom control than as-needed dosing for acute pain or fever 1. The analgesic effect typically lasts 6-8 hours, making the 6-8 hour dosing interval appropriate 1.