Skip to Content

Dicloxacillin use while Breastfeeding

Drugs containing Dicloxacillin: Dynapen, Dycill, Pathocil

Dicloxacillin Levels and Effects while Breastfeeding

Summary of Use during Lactation

Limited information indicates that dicloxacillin levels in milk are low and are not expected to cause adverse effects in breastfed infants. It is frequently used to treat mastitis in nursing mothers.[1][2][3] 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. Dicloxacillin is acceptable in nursing mothers.

Drug Levels

Maternal Levels. After a single oral dose of 250 mg of dicloxacillin in 2 women, milk levels ranged from 0.2 to 0.3 mg/L between 2 and 4 hours after the dose. The drug was undetectable in milk at 1 and 6 hours after the dose.[4]

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

Effects in Breastfed Infants

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

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


1. Berth WL, Schauberger CW, Alvarado MA, Mathiason MA. Telephone-based management of lactation mastitis. J Reprod Med. 2009;54:291-4. PMID: 19517693

2. Amir LH. ABM clinical protocol #4: Mastitis, revised March 2014. Breastfeed Med. 2014;9:239-43. PMID: 24911394

3. Berens PD. Breast pain: Engorgement, nipple pain, and mastitis. Clin Obstet Gynecol. 2016;58:902-14. PMID: 26512442

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

Dicloxacillin Identification

Substance Name


CAS Registry Number


Drug Class

Antiinfective Agents

Antibacterial Agents


Administrative Information

LactMed Record Number


Last Revision Date



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.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.