Recommended Dose of Mefenamic Acid in Children
Mefenamic acid should be dosed at 6 mg/kg per dose in children, though it should generally be avoided as an antipyretic and reserved for pain or chronic inflammatory conditions due to safety concerns with NSAIDs in pediatric fever management. 1
Age Limitations and Safety Considerations
- Mefenamic acid is not recommended for routine fever management in children, as NSAIDs should be reserved for pain or chronic inflammatory conditions due to safety concerns 1
- The drug has been studied in children as young as 3 months, but specific FDA approval for pediatric use and lower age limits are not well-established in the available guidelines 2
- For infants under 6 months, ibuprofen (another NSAID) is generally not recommended, suggesting similar caution should apply to mefenamic acid 3
Dosing Schedule and Administration
- The standard dose is 6 mg/kg per dose when mefenamic acid is used 1
- The optimal antipyretic dose has been identified as 4 mg/kg in some older studies, though more recent evidence supports 6 mg/kg 2, 4
- Dosing intervals are not explicitly stated in the available evidence, but the antipyretic effect was measured over 6 hours in clinical studies 2
Clinical Efficacy Compared to Alternatives
- Mefenamic acid at 6 mg/kg produces similar antipyretic effects to high-dose paracetamol (20 mg/kg), with both being superior to standard-dose paracetamol (15 mg/kg) 1
- The time to reach normal temperature was approximately 85 minutes with mefenamic acid, compared to 97.5 minutes with standard-dose paracetamol 1
- Duration of antipyretic action may be longer with mefenamic acid (8.82 hours until next fever) compared to high-dose paracetamol (7.20 hours), though this difference was not statistically significant 1
Important Clinical Caveats
- High-dose paracetamol (20 mg/kg) achieves similar antipyretic effects to mefenamic acid and should be considered first-line, allowing mefenamic acid to be reserved for pain and anti-inflammatory indications 1
- The antipyretic potency of mefenamic acid appears to exceed its anti-inflammatory properties, being 2.5 times more potent than acetylsalicylic acid or paracetamol in older studies 2
- Adverse effects were negligible in clinical trials, but the general principle of avoiding NSAIDs for simple fever management in children remains important 1
Special Population: Preterm Infants
- In preterm infants with patent ductus arteriosus, mefenamic acid has been studied at 2 mg/kg every 24 hours, though this is a specialized indication unrelated to routine fever management 5
- Marked inter-individual variation exists in pharmacokinetics in this population, with plasma half-life ranging from 3.8 to 43.6 hours 5