Methotrexate use while Breastfeeding
Drugs containing Methotrexate: Otrexup, Trexall, Rasuvo, Methotrexate LPF Sodium, Rheumatrex Dose Pack, Folex PFS
Methotrexate Levels and Effects while Breastfeeding
Summary of Use during Lactation
Most sources consider breastfeeding to be contraindicated during maternal high-dose antineoplastic drug therapy with methotrexate. An abstinence period of at least 1 week after chemotherapy doses of methotrexate has been suggested. Limited information indicates that a maternal dose of methotrexate up to 65 mg (or 50 mg/square meter) produces low levels in milk, leading some authors to state that low single or weekly doses, such as those used for ectopic pregnancy or rheumatoid arthritis, are of low risk to the breastfed infant. If breastfeeding during long-term, low-dose methotrexate use is undertaken, monitoring of the infant's complete blood count and differential could be considered.
Maternal Levels. One patient who was 1 month postpartum given 22.5 mg (15 mg/square meter) methotrexate daily by mouth for choriocarcinoma. Milk was collected at various times of the first 12 days of therapy. A peak milk level of 2.3 mcg/L occurred 10 hours after the first dose. However, the milk level was relatively constant during the period from 4 to 10 hours after the dose, after which it began to drop. Peak milk levels on the second and third days of administration were 2.7 mcg/L. The authors estimated that a cumulative amount of 0.32 mcg would be excreted in milk during the first 12 hours after this dose.
A woman was given a single intramuscular dose of 65 mg (50 mg/square meter) of methotrexate for ectopic pregnancy. Six milk samples were obtained from 1 to 24 hours after the dose. Methotrexate was undetectable (<22.7 mcg/L) in all milk samples.
A woman with rheumatoid arthritis received hydroxychloroquine, sulfasalazine and prednisone 10 mg daily during pregnancy and postpartum. On day 151 postpartum, methotrexate 25 mg was given subcutaneously. Breastmilk samples were obtained at 2, 12 and 24 hours after the dose. Milk levels were 0.05 micromolar (22.7 mcg/L) in all samples which was considered detectable, but not quantifiable. If the infant were fully breastfed, it would receive 3.4 mcg/kg in the first 24 hours after administration, or about 1% of the weight-adjusted maternal dosage.
Infant Levels. Relevant published information was not found as of the revision date.
Effects in Breastfed Infants
On day 151 postpartum, weekly methotrexate 25 mg subcutaneously begun a nursing mother. The estimated intake of the infant at that time was 3.4 mcg/kg in the first 24 hours after administration. The mother continued to breastfeed (extent not stated) for an additional 9 months while receiving subcutaneous methotrexate 25 mg weekly. No adverse effects were noted in the infant.
Effects on Lactation and Breastmilk
Relevant published information was not found as of the revision date.
Alternate Drugs to Consider
1. Pistilli B, Bellettini G, Giovannetti E et al. Chemotherapy, targeted agents, antiemetics and growth-factors in human milk: How should we counsel cancer patients about breastfeeding? Cancer Treat Rev. 2013;39:207-11. PMID: 23199900
2. Johns DG, Rutherford LD et al. Secretion of methotrexate in human milk. Am J Obstet Gynecol. 1972;112:978-80. PMID: 5042796
3. Moretti ME, Lee A, Ito S. Which drugs are contraindicated during breastfeeding? Can Fam Physician. 2000;46:1753-7. PMID: 11013791
4. Ostensen M. Management of early aggressive rheumatoid arthritis during pregnancy and lactation. Expert Opin Pharmacother. 2009;10:1469-79. PMID: 19505214
5. Tanaka T, Walsh W, Verjee Z et al. Methotrexate use in a lactating woman with an ectopic pregnancy. Birth Defects Res A Clin Mol Teratol. 2009;85:494. Abstract. Assay sensitivity per Shinya Ito, MD. DOI: doi:10.1002/bdra.20605
6. Thorne JC, Nadarajah T, Moretti M, Ito S. Methotrexate use in a breastfeeding patient with rheumatoid arthritis. J Rheumatol. 2014;41:2332. PMID: 25362724
CAS Registry Number
Abortifacient Agents, Nonsteroidal
Folic Acid Antagonists
LactMed Record Number
Last Revision Date
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