What is the recommended dose of Motrin (ibuprofen) for an infant?

Infant Motrin (Ibuprofen) Dosing

For infants 6 months and older, administer ibuprofen 10 mg/kg per dose every 6-8 hours, with a maximum of 40 mg/kg per day; ibuprofen is NOT recommended for infants under 6 months of age. 1

Age-Based Dosing Guidelines

Infants 6 Months and Older

• Standard dose: 10 mg/kg per dose, administered every 6-8 hours 1
• Maximum daily dose: 40 mg/kg per day (typically 3-4 doses in 24 hours) 2
• Route: Oral preferred; rectal administration is less reliable due to erratic absorption, especially in young infants 2

Infants Under 6 Months

• Ibuprofen is generally NOT recommended for infants under 6 months of age 1
• For infants 3-6 months requiring antipyretic or analgesic therapy, acetaminophen is the only recommended option at 10-15 mg/kg per dose every 4-6 hours 1, 3
• If ibuprofen must be considered in the 3-6 month age group (exceptional circumstances only), the infant must weigh at least 5-6 kg and special attention must be given to hydration status 2

Practical Dosing Calculations

Weight-Based Dosing (for infants ≥6 months)

• 5-10 kg infant: 50-100 mg per dose
• 10-15 kg infant: 100-150 mg per dose
• Administer every 6-8 hours as needed 1, 2

Formulation Considerations

• Oral suspension concentration: Typically 100 mg/5 mL (infant drops may vary)
• Administration: Can be given with or without food, though meals may improve gastrointestinal tolerability 3
• Avoid rectal formulations when possible due to unpredictable absorption 2

Critical Safety Considerations

Hydration Status

• Ensure adequate hydration before and during ibuprofen administration, particularly in febrile infants who may have increased insensible losses 2
• Dehydration increases the risk of renal complications with NSAID use 2

Maximum Dosing Limits

• Never exceed 40 mg/kg per day or more than 4 doses in 24 hours 2
• The longer dosing interval (every 6-8 hours) compared to acetaminophen (every 4-6 hours) provides approximately 2.5 additional hours without fever over 24 hours when both medications are used 4

Common Pitfalls to Avoid

• Do not use in infants under 6 months unless under exceptional circumstances with specialist consultation 1, 2
• Verify the concentration of the suspension being used, as infant formulations may differ from children's formulations 3
• Avoid combining with other NSAIDs or products containing ibuprofen 3
• Document all dose times carefully to prevent inadvertently exceeding maximum recommended doses, particularly if alternating with acetaminophen 4

Alternating with Acetaminophen (if needed)

If both medications are required for fever management in infants ≥6 months:

• Acetaminophen: 10-15 mg/kg every 4-6 hours 1
• Ibuprofen: 10 mg/kg every 6-8 hours 1
• Stagger timing so medications are given every 3-4 hours if both are needed 1
• Carefully record all doses to avoid exceeding maximum daily limits for either medication 4
• Parents should be aware that inadvertently exceeding maximum doses occurred in 8% of children receiving acetaminophen and 11% receiving ibuprofen in clinical trials 4

When to Choose Ibuprofen First

Ibuprofen should be the first-line antipyretic in children ≥6 months with fever, as it provides longer duration of action (6-8 hours vs 4-6 hours for acetaminophen) and may be more effective at reducing fever 4

However, the relative benefits of adding acetaminophen (extra 2.5 hours without fever over 24 hours) must be weighed against the risk of inadvertently exceeding maximum recommended doses 4