Although interpatient variability exists, the dose of ranitidine in breastmilk is less than the dose used in newborn infants. Maternal ranitidine would not be expected to cause any adverse effects in breastfed infants. No special precautions are required.
Six women with established lactation who were 6 to 10 days postpartum were given a single dose of 150 mg of ranitidine orally. Average milk levels were 1.28, 1.42 and 1.02 mg/L at 2, 4 and 8 hours, respectively, after the dose; however, there was great interpatient variability in both peak levels and the time of the peak.
After 5 oral doses of ranitidine 150 mg every 12 hours in a 54-day postpartum woman, the highest measured milk level occurred 5.5 hours after the 5th dose and was 2.6 mg/L. The estimated half-life in milk was 2.9 hours.
Using the average peak milk level data from these 2 papers, an exclusively breastfed infant would receive an estimated maximum of 300 mcg/kg daily with a maternal dosage of 150 mg daily. This dosage is 20% of the dosage used intravenously in newborn infants for stress ulcer prophylaxis.
Relevant published information was not found as of the revision date.
Effects in Breastfed Infants:
One 54-day-old breastfed infant had no observable adverse effects after maternal ingestion of ranitidine 150 mg every 12 hours for 2 days.
Possible Effects on Lactation:
Histamine H2-receptor blockade is known to stimulate prolactin secretion. Ranitidine in intravenous doses over 100 mg or during long-term oral use have increased serum prolactin in some studies, but no reports of galactorrhea or effects on breastfeeding women were found as of the revision date. The prolactin level in a mother with established lactation may not affect her ability to breastfeed.
1. Riley AJ, Crowley P, Harrison C. Transfer of ranitidine to biological fluids: milk and semen. In: Misiewicz JJ, Wormsley KG, eds. The clinical use of ranitidine. Oxford: Medicine Publishing Foundation, 1982:78-81. 2. Kearns GL, McConnell RF Jr, Trang JM et al. Appearance of ranitidine in breast milk following multiple dosing. Clin Pharm. 1985;4:322-4. PMID:4039999 3. Knigge UP. Histaminergic regulation of prolactin secretion. Dan Med Bull. 1990;37:109-24. PMID:2188799 4. Perret G, Hugues JN, Louchahi M et al. Effect of a short-term oral administration of cimetidine and ranitidine on the basal and thyrotropin-releasing hormone-stimulated serum concentrations of prolactin, thyrotropin and thyroid hormones in healthy volunteers. A double-blind cross-over study. Pharmacology. 1986;32:101-8. PMID:3081918 5. Delitala G, Devilla L, Pende A et al. Effects of the H2 receptor antagonist ranitidine on anterior pituitary hormone secretion in man. Eur J Clin Pharmacol. 1982;22:207-11. PMID:6125393 6. Knigge U, Wollesen F, Dejgarrd A et al. Comparison between dose-responses of prolactin, thyroid stimulating hormone and growth hormone to two different histamine H-2 receptor antagonists in normal men. Clin Endocrinol (Oxf). 1981;15:585-92. PMID:6276054
CAS Registry Number:
Histamine H2 Antagonists
LactMed Record Number:
Last Revision Date:
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.