Summary of Use during Lactation

Limited information indicates that cloxacillin produces low levels in milk that are not expected to cause adverse effects in breastfed infants. Occasionally disruption of the infant's gastrointestinal flora, resulting in diarrhea or thrush have been reported with penicillins, but these effects have not been adequately evaluated. Cloxacillin is acceptable in nursing mothers.

Drug Levels

Maternal Levels. No studies have reported milk levels after oral cloxacillin. After a single intramuscular dose of 500 mg of cloxacillin in 2 women, milk levels ranged from 0.1 to 0.3 mg/L between 1 and 6 hours after the dose.[1]

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

Effects in Breastfed Infants

In a telephone follow-up study, 10 nursing mothers reported taking cloxacillin (dosage unspecified). Two mothers reported diarrhea in their infants. No rashes or candidiasis were reported among the exposed infants.[2]

Effects on Lactation and Breastmilk

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

Alternate Drugs to Consider

(Mastitis) Cephalexin; (Methicillin-resistant Staph. aureus) Doxycycline, Linezolid, Minocycline, Trimethoprim-Sulfamethoxazole, Vancomycin

References

1.

Matsuda S. Transfer of antibiotics into maternal milk. Biol Res Pregnancy. 1984;5:57-60.. [PubMed: 6743732]

2.

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. [PubMed: 8498418]

Substance Name

Cloxacillin

CAS Registry Number

61-72-3

Drug Class

Breast Feeding

Lactation

Anti-Infective Agents

Antibacterial Agents

Penicillins