Transgender PersonsPhase 4NCT05469204
Effect of Estrogen Treatment on Drug Metabolism and Transport
A Phase 4 study testing Midazolam oral solution, Digoxin Oral Tablet and Acetaminophen Oral Tablet in people with Transgender Persons, run by University of Washington at 1 site in United States.
Trial summary
This project will evaluate the effect of estrogen treatment on how other medications are processed by the body. Read more about this study
- Who is it for?
- Ages 18 to 55 yearsHealthy volunteers can take part
- Conditions the study is for
- Transgender Persons
- What is being tested?
- Midazolam oral solution, Digoxin Oral Tablet and Acetaminophen Oral Tablet
- Type of treatment
- Pill or oral medicine, Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 22 participants
- Where
- 1 siteUnited States
- Study dates
- 1 Nov 2022to 30 Jul 2025
- Phase
- Phase 4
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 55 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Self-identified trans* adult 18-55 years of age.
- Not taking estradiol treatment currently.
- Planning to start injectable estradiol or estradiol tablets for gender-affirming medical care.
Who cannot join
- Unwilling/unable to return for project follow-up visits.
- Unwilling/unable to provide written informed consent.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Effect of Gender-Affirming Estrogen Therapy on Drug Metabolism, Transport, and Gut Microbiota
This project will evaluate the effect of estrogen treatment on how other medications are processed by the body.
Read the detailed description
Estradiol is prepared as a medication that patients may take to increase hormone levels. Changes in estradiol concentrations in the body may affect how the body processes other medicines. The purpose of this study is to find out how estradiol therapy affects a single tracer dose of approved medicines in the blood (midazolam, digoxin, and acetaminophen) and to confirm estradiol treatment does not affect natural bacterial in the gut.
- Conditions
- Transgender Persons
- Being tested
- Midazolam oral solution, Digoxin Oral Tablet, Acetaminophen Oral Tablet, Midazolam Injectable Solution
- Keywords
- hormone therapy, estrogen treatment
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Midazolam oral solutionDrug
2 mg single-dose before and during estradiol treatment.
Digoxin Oral TabletDrug
0.25 mg single-dose before and during estradiol treatment.
Acetaminophen Oral TabletDrug
500 mg single-dose before and during estradiol treatment.
Midazolam Injectable SolutionDrug
1 mg intravenous single-dose before and during estradiol treatment.
| Study group | Role | What they receive |
|---|---|---|
| Healthy transgender adults | Other | Healthy transgender adults will be studied on two separate study days and serve as their own control. Receives: Drug: Midazolam oral solution; Drug: Digoxin Oral Tablet; Drug: Acetaminophen Oral Tablet; Drug: Midazolam Injectable Solution |
What is being measured
The primary outcome is the main question the study is designed to answer.
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 estradiol treatment.
Measured: 0-6 hours
digoxin renal clearance (treatment/control)
ratio of digoxin renal clearance in the presence to absence of gender-affirming estradiol treatment.
Measured: 0-48
Secondary outcomes (1)
midazolam Cmax ratio (treatment/control)
ratio of the maximum plasma concentration (Cmax) of midazolam in the presence to absence of gender-affirming estradiol treatment
Measured: 0-6 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Jul 2022
- Study start1 Nov 2022
- Primary completion30 Jul 2025
- Study completion30 Jul 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Transgender PersonsStudies of the same condition, open and under way.
- More trials run by University of WashingtonThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 4
- Primary purpose
- Other
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 22 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Washington
- Sponsor type
- University, hospital or other
- Collaborators
- National Institute of General Medical Sciences (NIGMS)
- Responsible party
- Principal investigator, Lauren Cirrincione, University of Washington
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05469204
- Sponsor's protocol ID
- STUDY00014091
- Other IDs
- 1K23GM147350
- Status last verified
- Jan 2026
- First submitted
- 19 Jul 2022
- Last updated
- 9 Jan 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 9 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effect of Gender-Affirming Estrogen Therapy on Drug Metabolism, Transport, and Gut Microbiota
- ClinicalTrials.gov ID
- NCT05469204
- Acronym / sponsor ID
- STUDY00014091
- Conditions
- Transgender Persons
- Keywords
- hormone therapy, estrogen treatment
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 22 participants (actual)
- Lead sponsor
- University of WashingtonUniversity, hospital or other
- Collaborators
- National Institute of General Medical Sciences (NIGMS)
- Study start
- 1 Nov 2022 (actual)
- Primary completion
- 30 Jul 2025 (actual)
- Study completion
- 30 Jul 2025 (actual)
- First posted
- 21 Jul 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This project will evaluate the effect of estrogen treatment on how other medications are processed by the body.
Detailed description
Estradiol is prepared as a medication that patients may take to increase hormone levels. Changes in estradiol concentrations in the body may affect how the body processes other medicines. The purpose of this study is to find out how estradiol therapy affects a single tracer dose of approved medicines in the blood (midazolam, digoxin, and acetaminophen) and to confirm estradiol treatment does not affect natural bacterial in the gut.
Study design
- Primary purpose
- Other
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Healthy transgender adults | Other | Drug: Midazolam oral solution, Drug: Digoxin Oral Tablet, Drug: Acetaminophen Oral Tablet, Drug: Midazolam Injectable SolutionHealthy transgender adults will be studied on two separate study days and serve as their own control. |
Who may qualify
- Ages
- 18 to 55 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (3 listed)
- Self-identified trans* adult 18-55 years of age.
- Not taking estradiol treatment currently.
- Planning to start injectable estradiol or estradiol tablets for gender-affirming medical care.
Key exclusion criteria (2 listed)
- Unwilling/unable to return for project follow-up visits.
- Unwilling/unable to provide written informed consent.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Midazolam oral solution2 mg single-dose before and during estradiol treatment. | Drug | Healthy transgender adults |
| Digoxin Oral Tablet0.25 mg single-dose before and during estradiol treatment. | Drug | Healthy transgender adults |
| Acetaminophen Oral Tablet500 mg single-dose before and during estradiol treatment. | Drug | Healthy transgender adults |
| Midazolam Injectable Solution1 mg intravenous single-dose before and during estradiol treatment. | Drug | Healthy transgender adults |
Primary outcome
midazolam AUC ratio (treatment/control)
Time frame: 0-6 hours
ratio of the area under of the plasma concentration time curve (AUC) of midazolam in the presence to absence of gender-affirming estradiol treatment.
digoxin renal clearance (treatment/control)
Time frame: 0-48
ratio of digoxin renal clearance in the presence to absence of gender-affirming estradiol treatment.
1 secondary outcome
midazolam Cmax ratio (treatment/control)
Time frame: 0-6 hours
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 9 Jan 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Midazolam oral solution, Digoxin Oral Tablet and Acetaminophen Oral Tablet in people with Transgender Persons, run by University of Washington at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 2 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 9 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
midazolam AUC ratio (treatment/control) (time frame: 0-6 hours). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 9 Jan 2026.