Diclofenac Injection in Lactation
Intramuscular diclofenac is safe to use during breastfeeding and does not require interruption of nursing. 1
Evidence-Based Recommendation
The 2020 Association of Anaesthetists guideline explicitly states that diclofenac has been used extensively during lactation and is considered safe to use during breastfeeding, with only small amounts detected in breast milk 1. This represents the highest quality guideline evidence available and should guide clinical practice.
Key Supporting Evidence
Milk Transfer Profile
- Minimal breast milk excretion: Only small amounts of diclofenac are detected in breast milk 1
- Low milk-to-plasma ratio: Recent research shows a milk-to-plasma drug concentration ratio of only 0.093, indicating very low mammary transfer 2
- Extensive clinical experience: Diclofenac has been widely used postpartum and during lactation without demonstrable adverse effects 1, 3
Clinical Context
- Preferred NSAID option: Among NSAIDs, ibuprofen, diclofenac, and naproxen are all considered safe during breastfeeding 1, 3
- No waiting period required: Breastfeeding can continue immediately after administration without need to "pump and dump" 1
- Postpartum pain management: Diclofenac is specifically mentioned as appropriate for postpartum analgesia in nursing mothers 4, 5
Important Caveats
FDA Label Considerations
The FDA drug label for diclofenac states "it is not known whether this drug is excreted in human milk" and recommends considering discontinuation of nursing or the drug 6. However, this conservative FDA language conflicts with extensive clinical evidence and international guidelines showing safety. The guideline evidence should take precedence in clinical decision-making.
Comparison to Other Analgesics
- Ibuprofen remains first-line: If choosing between NSAIDs, ibuprofen has the most extensive safety data in lactation 1, 3
- Avoid high-dose aspirin: Aspirin in analgesic doses should not be used during breastfeeding 1
- Acetaminophen alternative: While safe, recent data shows surprisingly high milk transfer (milk-to-plasma ratio 1.048), though clinical significance remains unclear 2
Practical Management
Use diclofenac IM when indicated for pain control in breastfeeding mothers without interrupting nursing. The route of administration (IM vs oral) does not change the safety profile for lactation. Monitor the infant for any unusual symptoms as standard practice, though adverse effects are not expected given the low milk concentrations.