Study of Cimetidine Drug Transport in Breast Milk of Healthy Lactating Women Assessing OCT1 and BCRP Transporter Activity from 3 Weeks to 8 Months Postpartum

What this Trial Is About

Researchers are studying how the drug transporters OCT1 and BCRP work and are expressed in the breast tissue of healthy lactating women at three different times after giving birth. This phase I study aims to understand how drugs like cimetidine move through breast milk and how these transporters may affect this process. The study collects data at early, middle, and later postpartum periods to observe changes over time. Each participant will take a single oral dose of 200 mg cimetidine on three separate study days between 3 to 5 weeks, 3 to 4 months, and 6 to 8 months after delivery. Blood, urine, and breast milk samples will be collected over 12 hours following each dose. The study will measure cimetidine levels using specialized lab tests, and breast milk cells will be analyzed to quantify OCT1 and BCRP transporter expression. Each woman acts as her own control to compare results across time points. Participants will provide samples during each study visit, including blood, urine, and breast milk, to assess drug concentrations and transporter activity. Genetic testing will be done to understand individual differences in drug transporter genes. Researchers will monitor how well the breast clears cimetidine and how these transporters are expressed at the cellular level across the postpartum period. The study will help clarify drug safety and behavior in lactating women, with a total participation spanning up to eight months postpartum.

Drug Excretion in Breast Milk