title: Nitrendipine in human plasma and breast milk.
abstract: To assess the disposition of the dihydropyridine calcium antagonist, nitrendipine, in lactating mothers, we studied three breast-feeding women to determine simultaneous plasma and breast milk concentrations of nitrendipine and its inactive pyridine analog metabolite after both a single 10 mg oral dose and 5 days of continuous therapy (20 mg per day). Nitrendipine was excreted in breast milk at peak concentrations ranging from 4.3 to 6.5 ng/ml 1-2 h after acute dosing while its inactive pyridine metabolite ranged from 6.9 to 11.9 ng.ml-1. After 5 days of dosing, Cmax remained in the same range and the breast milk/whole plasma concentration ratio for nitrendipine was 0.2 to 0.5. On the fourth day of continuous dosing, average concentrations of nitrendipine from 24-h collections of the milk were 1.1 to 3.8 ng.ml-1. Thus, nitrendipine and its metabolite are excreted in very low concentrations in human breast milk. Based on a maternal dose of 20 mg daily, a newborn infant would ingest an average of 1.7 micrograms of nitrendipine per day, or a relative dose of 0.095%.
authors.affiliation: Section of Hypertension and Vascular Diseases, University of Connecticut School of Medicine, Farmington.
authors.forename: W B
authors.initials: WB
authors.lastname: White
authors.forename: S C
authors.initials: SC
authors.lastname: Yeh
authors.forename: G J
authors.initials: GJ
authors.lastname: Krol
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008895:Milk, Human / Q000378:metabolism*; D009568:Nitrendipine / Q000097:blood / Q000493:pharmacokinetics*; D011725:Pyridines / Q000097:blood
chemical_list: D011725:Pyridines; D009568:Nitrendipine