What is the appropriate ibuprofen dose for an 83‑lb (≈38 kg) child?

Ibuprofen Dosage for 83 lb Child

For an 83 lb (37.6 kg) child, administer ibuprofen 10 mg/kg per dose (approximately 380 mg), which can be given every 6-8 hours, not to exceed 40 mg/kg/day (approximately 1,500 mg/day). 1

Weight-Based Dosing Calculation

• At 83 lb (37.6 kg), this child falls below the 40 kg threshold, meaning pediatric weight-based dosing should be used rather than standard adult dosing 2
• The recommended dose is 10 mg/kg per dose, which equals approximately 380 mg for this child 1, 3
• This dose can be administered every 6-8 hours (3-4 times daily) 3
• The maximum daily dose is 40 mg/kg/day, which equals approximately 1,500 mg/day for this child 1, 3

Dosing Frequency and Administration

• Administer every 6-8 hours as needed for fever or pain, with a maximum of 3-4 doses in 24 hours 3, 4
• The effective dose range is 7.5-10 mg/kg, with 10 mg/kg providing optimal antipyretic and analgesic effect 4
• Maximum temperature reduction occurs 3-4 hours after administration, with duration of action typically 6-8 hours 4
• Ibuprofen can be given with food to improve gastrointestinal tolerability, though this is not required 3

Critical Dosing Threshold

• Children weighing less than 40 kg (88 lb) require pediatric weight-based calculations regardless of age 2
• At 37.6 kg, this child should not receive standard adult dosing (typically 400-600 mg per dose) 2
• The 40 kg threshold is the critical determinant for transitioning to adult dosing regimens 2

Safety Considerations

• Short-term use of ibuprofen is considered safe in children when special attention is given to hydration 3
• The child should have adequate fluid intake during ibuprofen therapy 3
• Avoid exceeding the maximum recommended daily dose of 40 mg/kg/day to prevent toxicity 1, 3
• Parents should carefully record all dose times to avoid accidentally exceeding maximum recommended doses 5

Common Pitfalls to Avoid

• Do not use age alone to determine dosing—weight is the critical factor for children near the 40 kg threshold 2
• Do not round up to adult dosing simply because the child is close to 40 kg; use actual body weight of 37.6 kg for calculations 2
• Avoid the rectal route as it has erratic absorption, especially in younger patients 3
• Do not combine with other antipyretics without careful dose tracking, as this increases risk of exceeding maximum recommended doses 5

Practical Dosing Example

For this 83 lb (37.6 kg) child:

• Single dose: 380 mg (10 mg/kg × 37.6 kg)
• Frequency: Every 6-8 hours as needed
• Maximum daily dose: 1,500 mg (40 mg/kg × 37.6 kg)
• Maximum number of doses: 3-4 times in 24 hours 3, 4