Risks to the infant
Of note, among the limited information available, a possible case of thrombocytopenia, bleeding time alteration and subsequent anemia in an infant seven days of life whose mother took a beta-lactam plus .
Known pharmacokinetics indicate that the peak concentration is reached in 4 to 5 hours of dosing, declining slowly over the next twelve hours. Based on a study of one case  , the authors estimate that probably the exclusively breastfed child receives a maximum of 2.2-2.8% of the maternal dose adjusted by weight. There is no reliable information on the levels of naproxen in children.
Telephone follow-up of twenty children whose mothers received naproxen revealed that one of the infants had vomiting and two had drowsiness , although they were not serious.
Influence on breastfeeding
No data are available about the possible influence of naproxen on breastfeeding.
Naproxen is considered compatible with breastfeeding, but there are alternatives that are probably safer.
1. Fidalgo I, Correa R, Gomez Carrasco JA et al. Anemia aguda, rectorragia y hematuria asociadas a la ingestion de naproxeno. An Esp Pediatr. 1989; 30:317-9.
2. Jamali F, Tam YK, Stevens RD. Naproxen excretion in breast milk and its uptake by suckling infant. Drug Intell Clin Pharm. 1982; 16:475.
3. Jamali F, Stevens DRS. Naproxen excretion in milk and its uptake by the infant. Drug Intell Clin Pharm. 1983; 17:910-1.
4. Ito S, Blajchman A, Stephenson M et al. Prospective follow-up of adverse reactions in breast-fed infants exposed to maternal medication. Am J Obstet Gynecol. 1993;168:1393-9.
Warning of the manufacturer:
Naproxen has been found in the milk of nursing mothers. The use of naproxen should be avoided in patients during lactation.