When should I check my child's fever after giving them Tylenol (acetaminophen) and Motrin (ibuprofen)?

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Last updated: November 17, 2025View editorial policy

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When to Check Your Child's Fever After Giving Tylenol and Motrin

Check your child's temperature 4 hours after giving the medications, as this is when you can expect to see the maximum fever reduction from both acetaminophen (Tylenol) and ibuprofen (Motrin).1, 2

Optimal Timing for Temperature Checks

  • At 4 hours post-dose: This represents the peak antipyretic effect for both medications when used together or alternately, making it the most informative time to assess treatment response 1, 2

  • At 1 hour post-dose: You may see some early temperature reduction (approximately 0.27°C lower with combined therapy), but this is not the full effect 3

  • At 24 hours: If you're using an alternating regimen, combined therapy can provide approximately 4-7 additional hours without fever over a 24-hour period compared to single-agent therapy 3, 4

What to Expect When Checking

  • Temperature reduction: Combined or alternating therapy typically lowers temperature by 0.5-0.7°C more than single-agent therapy at the 4-hour mark 3, 5

  • Fever clearance: Children receiving both medications tend to clear their fever faster (approximately 23 minutes sooner than acetaminophen alone) 4

  • Duration without fever: Combined therapy results in more time spent without fever—up to 55 minutes more in the first 4 hours compared to acetaminophen alone 4

Important Caveats

  • Treatment goal: Remember that the goal is treating your child's discomfort, not just reducing the number on the thermometer 6

  • Hydration matters: Ensure adequate fluid intake during fever management 6

  • Dosing intervals: If using alternating therapy, medications are typically given every 4 hours (alternating between the two), while single-agent therapy uses 6-hour intervals for acetaminophen or 8-hour intervals for ibuprofen 2

  • When to worry: If fever persists beyond 5 days without clear cause, or if your child appears seriously ill regardless of temperature, seek medical evaluation 7

References

Research

Comparison of multidose ibuprofen and acetaminophen therapy in febrile children.

American journal of diseases of children (1960), 1992

Research

Combined and alternating paracetamol and ibuprofen therapy for febrile children.

Evidence-based child health : a Cochrane review journal, 2014

Research

Antipyretic efficacy of ibuprofen and acetaminophen in children with febrile seizures.

Archives of pediatrics & adolescent medicine, 1995

Guideline

Management of Fever

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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