What is the recommended ibuprofen dose and dosing interval for a 50‑lb (≈23‑kg) child?

Ibuprofen Dosing for a 50-lb Child

For a 50-lb (approximately 23-kg) child, administer ibuprofen 230 mg (10 mg/kg) every 8 hours, with a maximum of 3 doses in 24 hours, not exceeding 920 mg/day (40 mg/kg/day). 1

Weight-Based Calculation

• The standard pediatric dose is 10 mg/kg per dose for children weighing less than 40 kg, which equals 230 mg for this 23-kg patient 2, 1
• This dose falls within the evidence-based effective range of 7.5–10 mg/kg demonstrated in clinical trials 3
• The dose should be administered every 8 hours (3 times daily), allowing adequate spacing between doses 2, 1

Practical Administration

• Round the calculated 230 mg dose to 200–250 mg depending on available tablet or liquid formulation strengths (e.g., 200 mg tablets or appropriate volume of oral suspension) 1
• For a child weighing more than 23 kg but less than 40 kg, weight-based calculation of 10 mg/kg remains the most accurate approach rather than using fixed age-based dosing 1
• The oral route is preferred, as rectal administration shows erratic absorption, especially in younger children 4

Maximum Daily Limits

• The maximum daily dose must not exceed 40 mg/kg/day, which equals approximately 920 mg/day for this 23-kg child 2, 1, 4
• This translates to a maximum of 3 doses in 24 hours when dosing every 8 hours 1
• Peak temperature reduction occurs 3–4 hours after administration 3

Critical Safety Considerations

• Ensure adequate hydration before and during ibuprofen administration, as this is particularly important for safe use in pediatric patients 4
• Do not combine with other NSAID medications without dose adjustment to avoid inadvertent overdosing 1
• Carefully record all dose times to prevent accidentally exceeding the maximum recommended daily dose—parents frequently misdose antipyretics, with over 50% giving inaccurate doses in one study 5, 6

Common Pitfalls to Avoid

• Beware of "hidden sources" of NSAIDs in combination over-the-counter medications (e.g., cold and flu preparations) that may contain ibuprofen 1
• Weight-based dosing is superior to age-based dosing—caregivers who base dosing on weight are significantly less likely to give inaccurate doses 5
• Parents often exceed the recommended maximum number of doses, with 11% exceeding the limit in clinical trials 6
• Ibuprofen has a longer duration of action than acetaminophen (paracetamol), so dosing more frequently than every 6–8 hours is unnecessary and increases toxicity risk 3, 6