Do ibuprofen and its active metabolites appear in breast milk at clinically significant levels, and is ibuprofen safe for a lactating mother to use?

Ibuprofen and Breast Milk: Safety Profile

Ibuprofen is completely safe for breastfeeding mothers and does not require interruption of nursing or discarding of breast milk, as ibuprofen and its metabolites are excreted into breast milk at clinically insignificant levels. 1

Excretion into Breast Milk

• Ibuprofen appears in breast milk at extremely low concentrations, with less than 1 mg per day excreted when mothers take up to 400 mg every 6 hours. 2
• The relative infant dose is less than 0.38% of the weight-adjusted maternal dose, well below the 10% safety threshold established by breastfeeding guidelines. 1
• In a controlled study of 12 post-cesarean patients taking 400 mg every 6 hours, no measurable amounts of ibuprofen were detected in breast milk samples using assay methodology capable of detecting concentrations as low as 1 microgram/ml. 2
• Ibuprofen is not excreted in substantial concentrations into breast milk, making it one of the safest analgesic options for lactating women. 3

Active Metabolites

• Ibuprofen undergoes biotransformation primarily to glucuronide conjugate metabolites that are excreted in urine, with little unchanged drug eliminated. 3
• Minor reactive metabolites include ibuprofen-S-acyl-glutathione and downstream products (ibuprofen-N-acyl-cysteinylglycine, ibuprofen-N-acyl-cysteine), but these are present in trace amounts even in maternal urine (6.0 µg, 1.7 µg, and 0.2 µg excreted over 10 hours, respectively). 4
• There is no evidence that these metabolites transfer into breast milk at clinically relevant concentrations, and they pose no documented risk to breastfed infants. 1, 2

Pharmacokinetic Properties Supporting Safety

• Ibuprofen has a short plasma half-life of approximately 1.5 hours, which reduces accumulation risk in both mother and infant. 1, 2
• High protein binding (concentration-dependent binding to plasma albumin) limits the free drug fraction available to transfer into breast milk. 1, 3
• The drug lacks development of pathologically related metabolites that cause irreversible tissue damage, unlike some other analgesics. 5

Clinical Recommendations

• Mothers can take ibuprofen immediately without any waiting period before breastfeeding; expressing and discarding breast milk is completely unnecessary and offers no safety benefit. 1
• Use the lowest effective dose for the shortest duration needed, though ibuprofen remains safe even at doses up to 400 mg every 6 hours. 1, 2
• Combining ibuprofen with paracetamol (acetaminophen) provides multimodal analgesia and is encouraged to optimize pain control while minimizing total NSAID exposure. 1

Special Considerations for Young Infants

• Extra caution should be exercised when the infant is less than 6 weeks of age (corrected for gestation) due to immature hepatic and renal function, though ibuprofen remains a safe option even in this population. 1
• No special monitoring of the infant is required when mothers take ibuprofen during breastfeeding, unlike medications that require observation for sedation or other adverse effects. 1

Guideline Society Endorsements

• The Association of Anaesthetists explicitly lists ibuprofen as compatible with breastfeeding, with no requirement to interrupt nursing. 1
• The American Academy of Pediatrics recommends ibuprofen as a preferred non-opioid analgesic for breastfeeding mothers, with a favorable safety profile. 1
• The European League Against Rheumatism (EULAR) states that ibuprofen has the most reassuring data among all NSAIDs during lactation. 1

Common Pitfall to Avoid

• The FDA label states "it is not known whether this drug is excreted in human milk" and suggests considering discontinuation of nursing or the drug 6, but this outdated labeling contradicts extensive clinical evidence and current guideline recommendations from multiple professional societies demonstrating ibuprofen's safety during lactation. 1, 2
• Opioids should not be used as default alternatives to ibuprofen, as they carry significantly higher risks of infant sedation, respiratory depression, and mortality compared to ibuprofen's negligible risk profile. 1