Drug Levels and Effects:

Summary of Use during Lactation:

Famotidine is used in newborn infants in higher dosages than are transmitted in breastmilk.[1] Famotidine would not be expected to cause any adverse effects in breastfed infants. No special precautions are required.

Drug Levels:

Maternal Levels.

Eight women who had "recently given birth" (not defined, but apparently within a few days postpartum) were given famotidine 40 mg orally. An average peak breastmilk level of 72 mcg/L occurred 6 hours after the dose.[2] Using the peak milk level data from this study, an exclusively breastfed infant would receive an estimated maximum of 0.01 mg/kg daily with this maternal dosage regimen or less than 2% of the maternal weight-adjusted dosage.

Seven women were given oral famotidine 40 mg daily in 2 or 4 divided doses for 3 days at 12 to 16 weeks postpartum. Average concentrations of famotidine in breastmilk were 53 and 55 mcg/L at 3 and 6 hours after a dose, respectively.[3]

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.

Possible Effects on Lactation:

Histamine H2-receptor blockade is known to stimulate prolactin secretion.[4] Oral famotidine usually does not affect serum prolactin levels, but rare cases of hyperprolactinemia and galactorrhea have been reported.[5][6] The prolactin level in a mother with established lactation may not affect her ability to breastfeed.

Alternate Drugs to Consider:



1. Orenstein SR, Shalaby TM, Devandry SN et al. Famotidine for infant gastro-oesophageal reflux: a multi-centre, randomized, placebo-controlled, withdrawal trial. Aliment Pharmacol Ther. 2003; 17(9):1097-107. PMID:12752346
2. Courtney TP, Shaw RW, Cedar E et al. Excretion of famotidine in breast milk. Br J Clin Pharmacol. 1988;26:639P. Abstract.
3. Wang X, Zhan Y, Hankins GD et al. Pharmacokinetics of famotidine in pregnant women. Am J Obstet Gynecol. 2011;204:S72-3. Abstract.
4. Knigge UP. Histaminergic regulation of prolactin secretion. Dan Med Bull. 1990;37:109-24. PMID:2188799
5. Delpre G, Lapidot M, Lipchitz A et al. Hyperprolactinaemia during famotidine therapy. Lancet. 1993;342:868. Letter. PMID:8104296
6. Guven K, Kelestimur F. Hyperprolactinemia and galactorrhea with standard-dose famotidine therapy. Ann Pharmacother. 1995;29:788. Letter. PMID:8520102

Substance Identification:

Substance Name:


CAS Registry Number:


Drug Class:

  • Anti-Ulcer Agents

  • Histamine H2 Antagonists

  • Administrative Information:

    LactMed Record Number:


    Last Revision Date:

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