Atenolol Pharmacokinetics and Excretion in Breast Milk during the first 6–8 Months Postpartum

摘要

Our objectives were to evaluate the time course for atenolol pharmacokinetics in lactating women postpartum and to quantify atenolol plasma concentrations in their 3–4 months old nursing infants. Data were collected over one dosing interval from lactating women treated with atenolol for therapeutic reasons, at 2–4 weeks (n=32), 3–4 months (n=22), and 6–8 months (n=17) postpartum. A single blood sample was collected from 15 nursing infants (3–4 months of age) of the mothers participating in the study. At 2–4 weeks, 3–4 months, and 6–8 months postpartum, atenolol infant dose, relative to the mother’s weight-adjusted dose, were 14.6 ± 7.6%, 8.3 ± 5.2% and 5.9 ± 2.9%, respectively. Over this time, maternal atenolol pharmacokinetics did not change to a clinically significant extent. Atenolol concentrations were below assay quantification limits (< 10 ng/mL) in the plasma of all 3–4 months old nursing infants studied. Our findings support the careful use of atenolol during breastfeeding, since in the vast majority of healthy, term infants, atenolol concentrations will be too low to be clinically relevant. Premature infants and those with kidney disease require further study. Infant exposure depends on maternal dose and decreases during the first 6–8 months postpartum.