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Completed

NCT Number: NCT05116293

Effect of Testosterone Treatment on Drug Metabolism and Transport

This project will evaluate the effect of gender-affirming testosterone treatment on how other medications are processed by the body.

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Key information

Conditions

Transgender Persons

Age range

18 year–60 year

Sex eligibility

All sexes

Study type

Observational

Primary location

University of Washington

Seattle, Washington, 98195, United States

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Self-identified trans* adult at least 18 years of age.
  • Not taking testosterone treatment currently.
  • Planning to start testosterone treatment through care provider for gender-affirming medical care.

Exclusion criteria

  • Unwilling/unable to return for project follow-up visits.
  • Unwilling/unable to provide written informed consent.

Treatment and study plan

Midazolam oral solution

Drug

Oral syrup

Digoxin Oral Tablet

Drug

Oral tablet

Acetaminophen Oral Tablet

Drug

Oral tablet

Primary outcomes

  1. midazolam AUC ratio (treatment/control)

    Time frame: 0-48 hours

    ratio of the area under of the plasma concentration time curve (AUC) of midazolam in the presence to absence of gender-affirming testosterone treatment.

Secondary outcomes

  1. midazolam Cmax ratio (treatment/control)

    Time frame: 0-48 hours

    ratio of the maximum plasma concentration (Cmax) of midazolam in the presence to absence of gender-affirming testosterone treatment

Sponsors and collaborators

Lead sponsor

University of Washington

Other

Registry information

Official study title

Effect of Gender-Affirming Testosterone Therapy on Drug Metabolism, Transport, and Gut Microbiota

Important dates

Study start
2021
Primary completion
2024
Study completion
2025
First posted
Nov 11, 2021
Registry last updated
May 4, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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