Skip to main content

Ampicillin and Sulbactam use while Breastfeeding

Medically reviewed by Last updated on Aug 4, 2022.

Ampicillin and Sulbactam Levels and Effects while Breastfeeding

Summary of Use during Lactation

Limited information indicates that ampicillin-sulbactam 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. Ampicillin-sulbactam is acceptable in nursing mothers.

Drug Levels

Maternal Levels. In 3 mothers who received intramuscular ampicillin 2 grams daily, milk levels ranged from 0.3 to 0.9 mg/L.In 3 mothers who received 4 grams daily intramuscularly, milk levels ranged from 0.4 to 0.9 mg/L. In all cases, peak milk levels occurred 3 hours after the dose. The breastfed infant was estimated to receive from 0.08 to 0.2 mg daily of ampicillin with these doses.[1]

In 15 women receiving ampicillin 500 mg 4 times daily by intramuscular injection, average milk ampicillin levels were as follows: 0.11 mg/L at 30 minutes after the injection; 0.21 mg/L at 1 hour, 0.17 at 2 hours, 0.27 mg/L at 4 hours and 0.26 mg/L at 6 hours after the injection.[2]

In 15 women given a single 2 gram dose of ampicillin intravenously, milk levels averaged 1.1 mg/L at 2 hours after the dose.[3]

A study in postpartum women with endometritis who received ampicillin 1 gram plus sulbactam 0.5 gram or ampicillin 2 grams plus 1 gram of sulbactam infused intravenously over 20 minutes found the average milk levels of ampicillin to be 1.7 mg/L with the highest level observed 3 mg/L. Sulbactam milk levels averaged 0.58 mg/L with the highest level observed 2.8 mg/L.[4]

Milk was collected at random times after 0.5 or 1 gram doses of sulbactam infused intravenously over 20 minutes. Little fluctuation occurred in milk levels over the first 8 hours after the dose with little difference in milk levels between the two dosages. Milk levels averaged 0.52 mg/L during this period with the highest level being 2.8 mg/L. Other levels from 10.5 to 20.5 hours after the dose ranged from 0.12 to 1.2 mg/L.[5]

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

Effects in Breastfed Infants

Relevant published information on ampicillin and sulbactam was not found as of the revision date; however, there are data on ampicillin alone. In a prospective follow-up study, 5 nursing mothers reported taking oral ampicillin (dosage unspecified). One mother reported diarrhea in her infant. No rashes or candidiasis were reported among the exposed infants.[6]

A small, controlled, prospective study had mothers monitor their infants for signs of adverse effects (furring of the tongue, feeding difficulties, changes in stool frequency and consistency, diaper rash, and skin rash). Weight change and the development of jaundice were also recorded. No statistical differences in these parameters were found between the infants of the control mothers and those of mothers taking oral ampicillin.[7]

Effects on Lactation and Breastmilk

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


Pons G, Rey E. [Passage of antibiotics in breast milk]. Med Mal Infect 1994;24 (Special Issue 1):1088-106. doi:10.1016/S0399-077X(05)80220-3. [CrossRef]
Amiraslanova LA, Emel'yanova AI, Fursova SA, et al. Akush Ginekol (Mosk). 1985;10(Oct):14–7. [Some aspects of ampicillin, kanamycin and cefuroxim pharmacokinetics in puerperant patients with endometritis] [PubMed: 2934996]
Zhang Y, Zhang Q, Xu Z. Zhonghua Fu Chan Ke Za Zhi. 1997;32:288–92. [Tissue and body fluid distribution of antibacterial agents in pregnant and lactating women] [PubMed: 9596854]
Foulds G, Miller RD, Stankewich JP, et al. The pharmacokinetics of subactam and ampicillin in postpartum women. In, Spitzy KH, Karrer K, eds. Proc 13th Int Congress Chemother 1983;1:23/17-23/2.
Foulds G, Miller D, Knirsch AK, et al. Sulbactam kinetics and excretion into breast milk in postpartum women. Clin Pharmacol Ther. 1985;38:692–6. [PubMed: 2998677]
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]
Campbell AC, McElnay JC, Passmore CM. The excretion of ampicillin in breast milk and its effect on the suckling infant. Br J Clin Pharmacol 1991;31:230p. Abstract. PMID: 2049243.

Substance Identification

Substance Name

Ampicillin and Sulbactam

CAS Registry Number


Drug Class

Breast Feeding


Anti-Infective Agents

Antibacterial Agents


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.

More about

Patient resources

Other brands


Professional resources

Further information

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