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Drugs and Lactation Database (LactMed®) [Internet]. Bethesda (MD): National Institute of Child Health and Human Development; 2006-.

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Drugs and Lactation Database (LactMed®) [Internet].

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Last Revision: September 21, 2020.

Estimated reading time: 1 minute

CASRN: 76824-35-6

image 135011273 in the ncbi pubchem database

Drug Levels and Effects

Summary of Use during Lactation

Famotidine doses in breastmilk result in infant dosages that are lower than those used in newborn infants. 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.[1] 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.[2]

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

Histamine H2-receptor blockade is known to stimulate prolactin secretion.[3] Oral famotidine usually does not affect serum prolactin levels, but rare cases of hyperprolactinemia and galactorrhea have been reported.[4,5] The prolactin level in a mother with established lactation may not affect her ability to breastfeed.

Alternate Drugs to Consider

Antacids, Cimetidine, Omeprazole, Pantoprazole, Sucralfate


Courtney TP, Shaw RW, Cedar E, et al. Excretion of famotidine in breast milk. Br J Clin Pharmacol 1988;26:639P. Abstract. PMID: 3207568.
Wang X, Zhan Y, Hankins GD, et al. Pharmacokinetics of famotidine in pregnant women. Am J Obstet Gynecol. 2011;204(1) Suppl:S72–3. Abstract.
Knigge UP. Histaminergic regulation of prolactin secretion. Dan Med Bull. 1990;37:109–24. [PubMed: 2188799]
Delpre G, Lapidot M, Lipchitz A, et al. Hyperprolactinaemia during famotidine therapy. Lancet 1993;342:868. Letter. PMID: 8104296. [PubMed: 8104296]
Guven K, Kelestimur F. Hyperprolactinemia and galactorrhea with standard-dose famotidine therapy. Ann Pharmacother 1995;29:788. Letter. PMID: 8520102. [PubMed: 8520102]

Substance Identification

Substance Name


CAS Registry Number


Drug Class

Breast Feeding


Anti-Ulcer Agents

Histamine H2 Antagonists

Gastrointestinal 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.

Copyright Notice

Attribution Statement: LactMed is a registered trademark of the U.S. Department of Health and Human Services.

Bookshelf ID: NBK501267PMID: 30000326


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