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Drugs and Lactation Database (LactMed) [Internet]. Bethesda (MD): National Library of Medicine (US); 2006-.

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Drugs and Lactation Database (LactMed) [Internet].

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Last Revision: November 16, 2020.

Estimated reading time: 1 minute

CASRN: 435-97-2

image 134974499 in the ncbi pubchem database

Drug Levels and Effects

Summary of Use during Lactation

Phenprocoumon is not approved for sale by the U.S. Food and Drug Administration (FDA). Limited information indicates that anticoagulant maternal doses of phenprocoumon produce low levels in milk. Until more data are available, shorter-acting anticoagulants are preferred, especially if the infant is younger than 2 months.

Drug Levels

Maternal Levels. One mother required anticoagulation postpartum was given phenprocoumon as an anticoagulant. Milk samples were obtained on days 27, 28 and 31 postpartum when her prothrombin time and phenprocoumon serum concentrations were stable. Milk phenprocoumon concentrations varied between 26 and 76 mcg/L and concentrations were higher in hindmilk than foremilk. A complete 24-hour milk collection contained a concentration of 33 mcg/L of phenprocoumon.[1]

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

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


von Kries R, Nocker D, Schmitz-Kummer E, et al. Monatsschr Kinderheilkd. 1993;141:505–7. [Transfer of phenprocoumon in breast milk. Is oral anticoagulation with phenprocoumon a contraindication for breastfeeding?] [PubMed: 8336747]

Substance Identification

Substance Name


CAS Registry Number


Drug Class

Breast Feeding



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.


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