Medications in Breast Milk: A Convenience Pharmacokinetic Study (The MedMilk Study)

The benefits of breastfeeding and human milk consumption by infants has been clearly demonstrated. Benefits to the infant include reduction of infant and childhood diseases and allergies. Benefits to the woman include more rapid return to pre-pregnancy weight and reduced risk of health problems such as cardiovascular disease and diabetes in the future. Many women take medications as part of their standard of care and for multiple medical reasons in the postpartum period, when breastfeeding occurs. This creates a need for information about the transfer of drugs taken by a woman into breast milk, and ultimately, to the infant. Unfortunately, there are limited pharmacokinetic (PK) data on many of the medications commonly taken by lactating women. Additionally, there are little data on how the PK of drugs are impacted by lactation, and how this may vary from woman to woman or with time throughout lactation. Uptake of drugs into breast milk can vary due to a number of factors, including drug lipophilicity; molecular weight; drug half-life; active transport in breast epithelial cells; protein binding in milk and plasma; and lipid composition of breast milk. In silico and animal models can provide some information on transfer of drugs into breast milk, however, there are large gaps remaining in our knowledge of drug transfer into human milk. This information is crucial to better inform providers and patients about the transfer of those drugs to human breast milk. The purpose of this study is to characterize the PK of specific drugs of interest taken by lactating women as part of their standard of care. The drugs of interest (DOI) will be based on medical relevance and availability throughout the course of the study. The purpose of this study is to characterize the PK of medications taken by lactating women as part of their standard of care.