Ampicillin and Sulbactam

Drug Levels and Effects:

Summary of Use during Lactation:

Ampicillin andsulbactamis acceptable to use during breastfeeding. Limited information indicates that maternal doses of ampicillin 2 grams andsulbactam1 gram produce 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, has been reported with penicillins, but these effects have not been adequately evaluated.

Drug Levels:

Maternal Levels.

In 3 mothers who received ampicillin 2 grams daily intramuscularly, milk levels ranged from 0.3 to 0.9 mg/L and in 3 mothers who received 4 grams dailyy 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 g dose of ampicillin intravenously, milk levels averaged 1.1 mg/L 2 hours after the dose.[3] Milk was collected at random times after 0.5 or 1 g doses ofsulbactaminfused 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.[4] A study in postpartum women with endometritis who received ampicillin 1 plussulbactam0.5 g or ampicillin 2 g plus 1 g ofsulbactaminfused 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.Sulbactammilk levels averaged 0.58 mg/L with the highest level observed 2.8 mg/L.[5]

Infant Levels.

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

Effects in Breastfed Infants:

No reports exist of infants breastfed during ampicillin andsulbactamtherapy; 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]

Possible Effects on Lactation:

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


1. Pons G, Rey E. [Passage of antibiotics into maternal milk]. Med Mal Infect. 1994;24 (special):1088-106.
2. Amiraslanova LA, Emel'yanova AI, Fursova SA et al. [Some aspects of ampicillin, kanamycin and cefuroxim pharmacokinetics in puerperant patients with endometritis.] Akush Ginekol (Mosk). 1985;Oct (10):14-7. PMID:2934996
3. Zhang Y, Zhang Q, Xu Z. [Tissue and body fluid distribution of antibacterial agents in pregnant and lactating women]. Zhonghua Fu Chan Ke Za Zhi.1997;32(5):288-92. PMID:9596854
4. Foulds G, Miller D, Knirsch AK et al.Sulbactamkinetics and excretion into breast milk in postpartum women. Clin Pharmacol Ther. 1985;6:692-6. PMID:2998677
5. 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;1:23-17-23/22.
6. 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. PMID:8498418
7. 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.

Substance Identification:

Substance Name:

Ampicillin andSulbactam

CAS Registry Number:


Drug Class:

  • Antiinfective Agents

  • Antibacterial Agents

  • Penicillins

  • Administrative Information:

    LactMed Record Number:


    Last Revision Date:

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