Pharmacokinetics and Safety of Commonly Used Drugs in Lactating Women and Breastfed Infants (CUDDLE)


This groundbreaking study, conducted by the PTN, is designed to assess the safety of commonly used off-patent medications when they are given to breastfeeding mothers.

It is common for new mothers to have symptoms or medical conditions that must be treated with drugs. These mothers often struggle with their decision to take their medications because of the fear that the drugs will harm their children. With this study, PTN aims to find doses of commonly used drugs that are safe for both mothers and their breastfed infants.

The study enrolled its first participant in October 2018 and will enroll approximately 50 lactating women, per drug, along with their breastfed infants, for each drug studied. Initially 10 off-patent drugs will be studied, including medications used to treat bacterial infections, depression and anxiety, high blood pressure, diabetes, and chronic pain. Mothers will be enrolled in the study only if they are already taking one of the following study drugs as part of their routine care.

  • Azithromycin
  • Clindamycin
  • Escitalopram
  • Labetalol
  • Metformin
  • Nifedipine
  • Ondansetron
  • Oxycodone
  • Sertraline
  • Tranexamic Acid
  • Ciprofloxacin
  • Doxycycline
  • Levofloxacin
  • Methylphenidate
  • Sumatripan

Mothers who participate in the study provide samples of breastmilk, their blood, their infants’ blood, or a combination to help researchers understand which drugs pass into breastmilk and determine the safest dose. Mothers and infants will be co-enrolled and followed up to infant age ≤180 days.



    Enrolling identifier:

    Principal Investigator:

    Kanecia Zimmerman, MD, MPH
    Duke Health, Durham, NC


    Stephen Balevic
    Duke Health, Durham, NC

    Kevin Watt, MD, PhD
    University of Utah School of Medicine


    • Groundbreaking study to assess safety of drugs passed through breastmilk The Pediatric Trials Network (PTN) is undertaking a groundbreaking study to assess the safety of commonly used off-patent medications when they are given to breastfeeding mothers. The study will track how different drugs are passed through breastmilk to determine dosing levels that are safe for both mom and baby. Although the U.S. Food and Drug Administration ...