Mefenamic Acid Dosing in Children
Mefenamic acid is FDA-approved only for adolescents ≥14 years of age at a dose of 500 mg initial dose followed by 250 mg every 6 hours as needed, and it is NOT approved for use in younger children. 1
FDA-Approved Pediatric Dosing
For adolescents ≥14 years: The recommended dose is 500 mg as an initial dose followed by 250 mg every 6 hours as needed for acute pain relief, usually not exceeding one week of treatment 1
For primary dysmenorrhea in adolescents ≥14 years: 500 mg initial dose followed by 250 mg every 6 hours, starting with onset of bleeding and associated symptoms, typically for 2-3 days 1
For children <14 years: Mefenamic acid lacks FDA approval and official dosing guidelines for this age group 1
Off-Label Use in Younger Children (Research Evidence Only)
While not FDA-approved, research studies have evaluated mefenamic acid in younger pediatric populations:
Antipyretic dosing (off-label): Research has used 4-6 mg/kg as a single dose for fever reduction in children as young as 3-5 months 2, 3, 4
A 2022 randomized controlled trial demonstrated that mefenamic acid 6 mg/kg had similar antipyretic efficacy to high-dose paracetamol (20 mg/kg) and superior efficacy to standard-dose paracetamol (15 mg/kg) 2
Earlier studies from the 1970s identified 4 mg/kg as the optimal antipyretic dose in children aged 3 months to 15 years 3, 4
Critical Clinical Considerations
The lack of FDA approval for children <14 years reflects important safety concerns that must be prioritized:
NSAIDs carry risks of gastrointestinal bleeding, ulceration, and perforation that may be particularly concerning in pediatric populations 1
Mefenamic acid should be used at the lowest effective dose for the shortest duration consistent with treatment goals 1
Paracetamol (acetaminophen) remains the preferred first-line antipyretic in children given its established safety profile and FDA approval across all pediatric age groups 2
If NSAID therapy is required in children, ibuprofen has more extensive pediatric safety data and FDA approval for children ≥6 months 2
Common Pitfalls to Avoid
Do not extrapolate adult dosing using simple weight-based calculations for children, as this approach fails to account for developmental differences in drug metabolism and elimination 5, 6
Do not use mefenamic acid as a routine antipyretic in children when safer alternatives (paracetamol, ibuprofen) are available and appropriate 2
Do not exceed one week of treatment for acute pain indications, even in approved adolescent populations 1
Recognize that neonates and infants have immature drug elimination pathways, making them particularly vulnerable to adverse effects from medications lacking age-specific dosing data 6