Ibuprofen Dosing for a 17-lb Child
No, 2.5 mL every 6 hours of Motrin 100 mg/5 mL (which equals 50 mg per dose) is below the recommended therapeutic dose for a 17-lb (7.7 kg) child and should be increased to achieve adequate pain or fever control.
Correct Dosing Calculation
- The American Academy of Pediatrics recommends ibuprofen 10 mg/kg per dose every 6-8 hours for children 1
- For a 7.7 kg child, the appropriate dose is 77 mg per dose (10 mg/kg × 7.7 kg) 1
- Using Motrin 100 mg/5 mL concentration, this translates to approximately 3.8-4 mL per dose 1
- The proposed 2.5 mL dose delivers only 50 mg, which is 65% of the recommended dose and unlikely to provide adequate therapeutic effect 1
Dosing Interval Considerations
- The standard dosing interval for ibuprofen is every 8 hours, not every 6 hours 1
- While every 6 hours is not contraindicated, it increases the frequency of administration without clear benefit at therapeutic doses 1
- Maximum of 3 doses in 24 hours should not be exceeded 1
Maximum Daily Dose Safety
- The maximum daily dose is 30 mg/kg/day (231 mg total for this 7.7 kg child) 1
- At the corrected dose of 77 mg every 8 hours (3 doses daily), the total would be 231 mg/day, which is at the maximum safe limit 1
- The proposed 2.5 mL every 6 hours (50 mg × 4 doses = 200 mg/day) stays within safety limits but provides subtherapeutic individual doses 1
Practical Recommendation
Administer 4 mL (80 mg) of Motrin 100 mg/5 mL every 8 hours, not to exceed 3 doses in 24 hours 1. This provides adequate therapeutic dosing while maintaining safety margins and is easier for caregivers to remember than a 6-hour schedule.
Critical Safety Considerations
- Parents must be counseled to avoid all other products containing ibuprofen, including combination cold/flu remedies, as inadvertent double-dosing is a common error 1, 2
- Ibuprofen should be given with food to improve gastrointestinal tolerability, though this is not mandatory 1
- Monitor for signs of inadequate pain or fever control, which would indicate the need for dose adjustment rather than increased frequency 1
Common Pitfalls to Avoid
- Underdosing is a frequent error that leads to inadequate symptom control and parental frustration, prompting inappropriate dose escalation or addition of other medications 1
- Using infant drops concentration (50 mg/1.25 mL) versus children's suspension (100 mg/5 mL) without adjusting volume is a critical error—always verify the concentration on the bottle 2
- Exceeding 30 mg/kg/day increases risk of gastrointestinal and renal adverse effects, particularly with prolonged use 3, 4