Effect of gender-affirming Estrogen therapy on drug metabolism, transport, and gut microbiota

What: This is up to a 24-week study of your gender-affirming estrogen therapy.

Purpose: The purpose of this study is to determine the effect of estrogen therapy on the amount of certain medicines in your blood and on the natural bacteria in your gut.

To be eligible: At the screening visit, the study coordinator will review all the study eligibility criteria with you, and you will have blood tests and an ECG to determine if you can participate in the study. A few key criteria that must all be met to participate in the study are listed below:

● Self-identified trans* adult at least 18 years of age and
● Not currently taking gender-affirming hormone therapy and
● Planning to start estrogen therapy for feminization through your provider for medical care.

Study Visits: Participants will be asked to attend four study visits (before and 12-weeks after starting estrogen therapy):

1. Study Visit 1 will take place at the University of Washington Medical Center Translational Research Unit for an overnight visit (approximately 24 hours). During that time, you will be provided with a single dose of three approved medications by mouth (midazolam, digoxin, acetaminophen) and by injection into your vein (midazolam). Your blood will be drawn 20 times from a small tube placed in your arm. Your urine will also be collected. You will be asked by the study coordinator to collect a stool sample before this visit and bring it with you. You will be asked to collect your urine overnight and return the next morning to the School of Pharmacy for one 45- minute follow-up visit. During this follow-up, your blood will be drawn one time and the study coordinator will collect your overnight urine sample.

2. Study Visit 2 (12 weeks after starting estrogen therapy) will be similar to Study Visit 1.

Cost: There is no cost to participate in this study. Hormone therapy is not provided by the study.

Stipend: Participant compensation is available up to $1115

For more information, please contact:

Lauren Cirrincione (she/her),

Study Investigator

School of Pharmacy, University of Washington

Call/text: 650-353-7782

Email: [email protected]

Effect of Estrogen Treatment on Drug Metabolism and Transport