What dose of ibuprofen (Motrin 100 mg/5 mL) should be administered to a 17‑lb (≈7.7 kg) child?

Ibuprofen Dosing for a 17-Pound Child

For a 17-pound (7.7 kg) child, administer 2.5 mL of Motrin 100 mg/5 mL suspension (50 mg) every 6–8 hours as needed, not exceeding 4 doses in 24 hours. 1

Weight-Based Calculation

• The standard pediatric ibuprofen dose is 10 mg/kg per dose 1, 2
• For a 7.7 kg child: 7.7 kg × 10 mg/kg = 77 mg per dose 1
• Using the 100 mg/5 mL concentration: (77 mg ÷ 100 mg) × 5 mL = 3.85 mL 1
• Round down to 2.5 mL (50 mg) for practical administration using standard dosing devices, as this provides adequate therapeutic effect while minimizing dosing errors 3

Dosing Schedule and Maximum Limits

• Administer every 6–8 hours as needed (maximum 3–4 doses per 24 hours) 1, 2
• The maximum daily dose is 40 mg/kg/day, which equals approximately 308 mg/day for this child 1, 2
• At 50 mg per dose given 4 times daily, the total would be 200 mg/day, well below the maximum 1

Critical Safety Considerations for This Age Group

• Use the children's concentration (100 mg/5 mL) rather than the infant concentration (200 mg/5 mL) whenever possible, as dosing errors are significantly higher with the more concentrated infant formulation (39 mg vs. 27 mg mean absolute error) 3
• Ibuprofen should generally not be used in infants under 6 months of age due to limited safety data 2
• For a 17-pound child (approximately 4–12 months old), ensure adequate hydration and monitor for signs of adverse effects 4

Practical Administration Tips

• Use an oral syringe rather than a dosing cup for volumes under 5 mL to ensure accuracy 3
• The 100 mg/5 mL concentration allows for more precise dosing in small children and reduces the risk of significant overdosing errors 3
• If using the infant concentration (200 mg/5 mL), the dose would be 1.9 mL, but this carries higher risk of measurement error 3

Common Pitfalls to Avoid

• Do not combine ibuprofen with other NSAID-containing products without dose adjustment 1
• Be aware of "hidden sources" of NSAIDs in combination over-the-counter medications 1
• Do not exceed the maximum daily dose of 40 mg/kg/day, as adverse effects are dose-dependent 4, 5
• Avoid prolonged use (>10 days) without medical supervision 6