Recommended Dosage of Mefenamic Acid for Pediatric Patients
Mefenamic acid is not FDA-approved for use in children under 14 years of age. For adolescents ≥14 years, the recommended dose is 500 mg as an initial dose followed by 250 mg every 6 hours as needed, usually not to exceed one week. 1
Age-Based Recommendations
- For children under 14 years of age, mefenamic acid is not FDA-approved and should generally be avoided due to limited safety and efficacy data in this population 1
- For adolescents 14 years and older, the FDA-approved dosing is the same as adults: 500 mg initial dose followed by 250 mg every 6 hours as needed 1
- Treatment duration should typically not exceed one week for acute pain management 1
Off-Label Use in Younger Children
While not FDA-approved, some research has evaluated mefenamic acid in younger children:
- For antipyretic effects, a dose of 6 mg/kg has been studied in children and showed comparable efficacy to other antipyretics 2
- In very limited studies, 4 mg/kg has been used as an antipyretic dose in children aged 3 months to 15 years 3
- For preterm infants (in extremely limited research), 2 mg/kg every 24 hours has been studied 4
Important Safety Considerations
- Mefenamic acid belongs to the NSAID class and carries risks of gastrointestinal bleeding, ulceration, and perforation 1
- The FDA recommends using the lowest effective dose for the shortest duration consistent with treatment goals 1
- Mefenamic acid has lower water solubility (BCS class II drug), which may affect its absorption 5
- When used for fever, high-dose paracetamol (20 mg/kg) may provide similar antipyretic effects with potentially fewer safety concerns than mefenamic acid 2
Monitoring and Precautions
- Monitor for gastrointestinal side effects, which are common with NSAIDs 1
- Avoid use in children with renal impairment, as dosing adjustments have not been established for pediatric patients 1
- Consider alternative antipyretics like acetaminophen (paracetamol) for fever management in children under 14 years 2
- For pain management in younger children, consult with a pediatric specialist before considering off-label use 6
Clinical Pearls
- For adolescents with primary dysmenorrhea (≥14 years), mefenamic acid can be given as 500 mg initially followed by 250 mg every 6 hours, starting with the onset of menses and typically not needed for more than 2-3 days 1
- The antipyretic effect of mefenamic acid may be stronger than its anti-inflammatory and analgesic properties in some pediatric patients 3
- Consider that the metabolism of mefenamic acid may be reduced in very young infants, potentially leading to longer half-lives 4