An observational study in Transgender Persons, sponsored by University of Washington. Completed at 1 site in United States. Open to participants aged 18 Years to 60 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-05-04.
Sponsored by University of Washington · Observational
This project will evaluate the effect of gender-affirming testosterone treatment on how other medications are processed by the body.
Gender-affirming hormone therapy may include testosterone, a hormone that the body creates and uses naturally. Testosterone is prepared as a medication that patients may take to increase hormone levels. Changes in testosterone concentrations in the body may affect how the body processes other medicines. The purpose of this study is to find out how testosterone therapy affects a single tracer dose of approved medicines in the blood (midazolam, digoxin, and acetaminophen) and to confirm testosterone treatment does not affect natural bacterial in the gut.
University of Washington is the lead sponsor of 1,397 studies on the registry; 225 are open to participants now.
Of its 154 completed or terminated interventional studies of FDA-regulated products, 132 (86%) have results posted.
Counted across the registry records on this site, refreshed daily.
Transgender adults planning to take testosterone treatment.
Exclusion Criteria:
Oral syrup
Oral tablet
Oral tablet
midazolam AUC ratio (treatment/control)
ratio of the area under of the plasma concentration time curve (AUC) of midazolam in the presence to absence of gender-affirming testosterone treatment.
Time frame: 0-48 hours
midazolam Cmax ratio (treatment/control)
ratio of the maximum plasma concentration (Cmax) of midazolam in the presence to absence of gender-affirming testosterone treatment
Time frame: 0-48 hours
This study is completed, as verified in Apr 2026. You cannot join it, but the record below documents what was studied.
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University of Washington