TRANSFER OF PHENPROCOUMON IN MOTHERS MILK - IS AN ORAL ANTICOAGULANT WITH PHENPROCOUMON A CONTRAINDICATION FOR BREAST-FEEDING

As the passage of phenprocoumon into human milk has not been studied y et, mothers on oral anticoagulation with Phenprocoumon are advised to stop breastfeeding in order to avoid the potential hazards of vitamin K deficiency haemorrhage in their babies. We analysed the passage of P henprocoumon into human milk in a breastfeeding mother of a premature baby (gestational age 32 weeks), who required oral anticoagulation on day 19 post partum. The mother was advised to continue collecting her milk with an electric pump, and to resume breastfeeding, if a signific ant passage of the drug was excluded. Milk Sampling (fore and hind mil k pairs (n=2), formilk (n=4), 24 h pooled collections) for the Phenpro coumon analyses with an HPLC method was performed on days 27, 28, and 31 when the Quick's Prothrombin time was stable in the therapeutic ran ge (Phenprocoumon plasma concentrations: 1.8-2.2 mug/ml). Results: Phe nprocoumon was higher in hind than in foremilk. With constant plasma c oncentrations the variability between different foremilk samples was 2 6-76 ng/ml. The Phenprocoumon concentration in the 24 h pooled sample was 33 ng/ml. Estimates of the PhenProcoumon secretion into human brea st milk should be from pooled milk samples of a 24 h collection. Phenp rocoumon in human milk is only about 1/50 of the corresponding materna l plasma concentrations. The estimated daily Phenprocoumon intake from maternal milk in a baby drinking about 200 ml/kg/day is 6-8 mug/kg. T his is much less the average maintenance requirement for anticoagulati on with Phenprocoumon in children (about 50 mug/kg/day). Mothers on or al anticoagulation with Phenprocoumon - like those on Warfarin treatme nt - may be allowed to breastfeed their babies but supplementation wit h vitamin K1 accordingly is recommended.