There are insufficient clinical observations on using aceclofenac during breastfeeding. By this reason, safety of this drug during breastfeeding has not been established. Aceclofenac pharmacokinetics are not well known.
If an NSAID is needed, is preferable to select a better known drug.
Warning of the manufacturer:
In limited studies so far available, NSAIDs can appear in breast milk in very low concentrations. NSAIDs should, if possible, be avoided when breastfeeding.
The use of aceclofenac should therefore be avoided in pregnancy and lactation unless the potential benefits outweigh the possible risks to the foetus or infant.