If mefenamicacidis required by the mother, it is not a reason to discontinue breastfeeding. Because there is little published experience with mefenamicacidduring breastfeeding and it is potentially toxic, other agents may be preferred, especially while nursing a newborn or preterm infant.
Ten postpartum women received a 500 mg loading dose of mefenamicacidfollowed by 250 mg orally 3 times daily through the fourth postpartum day. Mefenamicacidand its metabolites were measured using an old, insensitive assay method. Milk samples taken 2 hours after the first dose of each day found average mefenamicacidmilk levels of 170 mcg/L (range 30 to 660 mcg/L), although these levels might be inaccurate because the concentration measured in blank milk samples in this study was 200 mcg/L and potentially active metabolites were not measured.
Ten postpartum women received a 500 mg loading dose of mefenamicacidfollowed by 250 mg orally 3 times daily. Infant serum and urine specimens were obtained one hour after nursing on the afternoon of the fourth day. Only 3 of the 10 infants had blood levels at or above the blank level of the assay (10 mg/L). Average urine recovery was similar to the blank level. Five of the 10 infants had urine levels greater than blank urine.
Effects in Breastfed Infants:
Ten newborns were breastfed for 4 days during maternal intake of mefenamicacid. No mention was made of infant side effects or lack thereof.
Possible Effects on Lactation:
Relevant published information was not found as of the revision date.
1. Buchanan RA, Eaton CJ, Koeff ST et al. The breast milk excretion of mefenamicacid. Curr Ther Res. 1968;10:592-6. PMID:4973976
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Nonsteroidal Antiinflammatory Agents
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