Drug Levels and Effects:

Summary of Use during Lactation:

Although no information is available on the use of meropenem during breastfeeding, beta-lactams are generally not expected to cause adverse effects in breastfed infants. Occasionally, disruption of the infant's gastrointestinal flora, resulting in diarrhea or thrush, has been reported with beta-lactams, but these effects have not been adequately evaluated.

Drug Levels:

Maternal Levels.

A woman with a history of NYHA class I heart failure was 3 days postpartum and developed a urinary tract infection and was treated with cephalexin until it was found that the organism was resistant to extended-spectrum beta-lactams. On day 6 postpartum, meropenem 1 gram IV every 8 hours was started. Five samples of hindmilk were obtained from day 6 to day 9 postpartum over 37 hours. The highest measured level was 644 mcg/L and the lowest was 246 mcg/L. Over the collection period the average breastmilk level was 480 mcg/L. The average infant intake was estimated to be 71 mcg/kg daily, which was 0.13% of the weight-adjusted maternal dosage. The maximum infant intake was estimated to be 97 mcg/kg daily, which was 0.18% of the weight-adjusted maternal dosage[1]

Infant Levels.

Relevant published information was not found as of the revision date.

Effects in Breastfed Infants:

An infant was breastfed (extent not stated) until the 4th month postpartum. At 2 months of age, his mother was given a 2-week course oftobramycinand meropenem for a cystic fibrosis exacerbation. The infant displayed no change in stool pattern during the maternal treatment and had normal renal function at 6 months of age.[2][3]

A mother received meropenem 1 gram IV every 8 hours for 7 days while exclusively breastfeeding her newborn. When questioned later, she stated that her infant had no oral thrush, watery diarrhea, or diaper dermatitis that required antifungal therapy during the month following her meropenem therapy.[1]

Possible Effects on Lactation:

Relevant published information was not found as of the revision date.


1. Sauberan JB, Bradley JS, Blumer J, Stellwagen LM. Transmission of meropenem in breast milk. Pediatr Infect Dis J. 2012;31:832-4. PMID:22544050
2. Festini F, Ciuti R, Taccetti G et al. Breast-feeding in a woman with cystic fibrosis undergoing antibiotic intravenous treatment. J Matern Fetal Neonatal Med. 2006;19:375-6. PMID:16801316
3. Festini F, Ciuti R, Repetto T et al. Safety of breast-feeding during an IVtobramycincourse for infants of CF women. Pediatr Pulmonol Suppl. 2004;27:288-9. Abstract.

Substance Identification:

Substance Name:


CAS Registry Number:


Drug Class:

  • Antiinfective Agents

  • Carbapenems

  • Administrative Information:

    LactMed Record Number:


    Last Revision Date:

    Disclaimer:Information presented in this database is not meant as a substitute for professional judgment. You should consult your healthcare provider for breastfeeding advice related to your particular situation. The U.S. government does not warrant or assume any liability or responsibility for the accuracy or completeness of the information on this Site.