Is mefenamic acid (nonsteroidal anti-inflammatory drug (NSAID)) safe to use during breastfeeding in a postpartum patient?

Mefenamic Acid During Breastfeeding

Mefenamic acid should be used with caution during breastfeeding, and safer NSAID alternatives—specifically ibuprofen or diclofenac—should be strongly preferred as first-line options. 1, 2

Primary Recommendation

While the FDA label states that "trace amounts of mefenamic acid may be present in breast milk," it recommends that "a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother." 3 However, this conservative FDA stance does not reflect the more nuanced evidence-based approach from recent international guidelines.

The critical issue is that mefenamic acid lacks the robust safety data available for other NSAIDs during lactation. 1, 4

Preferred NSAID Alternatives

The European League Against Rheumatism (EULAR) 2025 guidelines establish a clear hierarchy of NSAID safety during lactation:

• Ibuprofen has the most reassuring safety data among all NSAIDs during lactation and should be the first-choice NSAID. 1
• Diclofenac is the second safest option, with established compatibility during breastfeeding. 1, 2
• Both ibuprofen and diclofenac are explicitly listed as compatible with breastfeeding by the Association of Anaesthetists, with no requirement to interrupt nursing or express and discard breast milk. 1, 2

Clinical Algorithm for NSAID Selection During Breastfeeding

1. First-line choice: Ibuprofen at the lowest effective dose for the shortest duration needed 1
2. Second-line choice: Diclofenac if ibuprofen is contraindicated or ineffective 1, 2
3. Third-line options: Naproxen (safe despite longer half-life) 1
4. Avoid or use with extreme caution: Mefenamic acid due to limited safety data 3

Why Mefenamic Acid Is Not Preferred

• Limited lactation safety data: Unlike ibuprofen and diclofenac, mefenamic acid does not appear in the comprehensive EULAR or Association of Anaesthetists guidelines as a recommended NSAID during lactation 1, 2
• FDA caution: The FDA label explicitly raises concerns about nursing infant exposure, suggesting discontinuation of either nursing or the drug 3
• Safer alternatives exist: Multiple NSAIDs with extensive safety profiles are available, making the use of less-studied agents unnecessary 1, 4, 5

If Mefenamic Acid Must Be Used

If clinical circumstances absolutely require mefenamic acid (e.g., specific indication where other NSAIDs have failed):

• Use the lowest effective dose for the shortest possible duration 4, 5
• Time breastfeeding to avoid peak maternal serum concentrations (typically 2-4 hours post-dose) 6, 4
• Monitor the infant closely for unusual behavior, feeding difficulties, or gastrointestinal symptoms 2, 7
• Exercise extra caution if the infant is under 6 weeks of age (corrected for gestational age) due to immature hepatic and renal function 1, 2
• Consider monitoring premature or compromised infants more intensively 6

Common Pitfalls to Avoid

• Do not automatically discontinue breastfeeding: The benefits of breastfeeding typically outweigh theoretical minimal drug exposure risks with NSAIDs 8, 5
• Do not recommend "pump and dump": This is not evidence-based for NSAID use 1, 9
• Do not default to opioids: These carry significantly higher risks of infant sedation and adverse effects compared to NSAIDs 1, 2
• Do not ignore safer alternatives: When multiple NSAIDs with better safety profiles exist, choosing mefenamic acid requires strong clinical justification 1, 4

Benefits of Continued Breastfeeding

International guidelines emphasize that women should not be discouraged from breastfeeding while taking compatible medications, as breastfeeding provides short-term protection against infectious morbidity and long-term protection against inflammatory bowel disease, obesity, and diabetes for the infant, while reducing maternal risks of diabetes, hypertension, and multiple cancers. 8