Postural Tachycardia SyndromeEarly Phase 1NCT04140721
Autonomic Determinants of POTS - Pilot 2
A Early Phase 1 study testing Moxonidine Pill in people with Postural Tachycardia Syndrome, run by Vanderbilt University Medical Center at 1 site in United States.
Trial summary
Postural tachycardia syndrome (POTS) is a relatively common condition affecting mostly otherwise healthy young women. These patients have high heart rate and disabling symptoms during standing. Quality of life may be poor. Read more about this study
- Who is it for?
- Ages 18 to 55 years, women only
- Conditions the study is for
- Postural Tachycardia Syndrome
- What is being tested?
- Moxonidine Pill
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 48 participants
- Where
- 1 siteUnited States
- Study dates
- 31 Aug 2021to 31 Dec 2026
- Phase
- Early Phase 1
- Are there results?
- Not yet: the study is under way
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
- Women only
- No healthy volunteers
- Adult
Who may be able to join
- meets criteria for postural tachycardia syndrome (POTS)
- a heart rate increase of ≥30 beats/min within 10 minutes of upright posture;
- lack of orthostatic hypotension (blood pressure fall ≥ 20/10 mmHg within 3 minutes of standing); and
- chronic symptoms during upright posture over at least 6 months, in the absence of any other acute cause.
- in the follicular phase of the menstrual cycle (days 5-13 of a 28-day cycle)
- POTS with primary central sympathetic activation (psPOTS) as defined as having resting MSNA ≥ 25 bursts/min
- able and willing to provide informed consent.
Who cannot join
- pregnancy,
- smoker,
- BMI>30 kg/m2,
- deconditioned status (if available VO2max<80% of predicted)
- unable to withdraw from medications known to affect autonomic function, blood pressure or blood volume
- systemic illnesses known to produce autonomic neuropathy, including but not limited to diabetes mellitus, amyloidosis, monoclonal gammopathies, and autoimmune neuropathies.
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- arteriosclerotic disease of carotid artery. History of neck surgery.
- conditions associated with inflammatory processes, such as coronary artery disease, hypertension, smoking, hypercholesterolemia (or on statin therapy), rheumatoid arthritis, diabetes,
- treatment with oral corticosteroids, current infections (e.g., urinary tract infection), or use of non-steroidal anti-inflammatory drugs.
- other factors which in the investigator's opinion would prevent the subject from completing the protocol including clinically significant abnormalities in clinical, mental or laboratory testing.
Trial locations and contacts
1 site in 1 country.
United States1 site
Vanderbilt University Medical Center
Nashville, Tennessee, 37221
About this study
Official title: Autonomic Determinants of Postural Tachycardia Syndrome (Chronic Pilot Study 2)
Postural tachycardia syndrome (POTS) is a relatively common condition affecting mostly otherwise healthy young women. These patients have high heart rate and disabling symptoms during standing. Quality of life may be poor. The sympathetic nerves in the autonomic nervous system help to maintain normal blood pressures and heart rates during activities of daily life.
The purpose of this study is to determine the importance of sympathetic activation as a cause of orthostatic symptoms. The investigators will assess the effects of a blood pressure medication (Moxonidine) on the symptoms during standing. Moxonidine lowers sympathetic activity. The investigators believe patients with high resting sympathetic activity might benefit from Moxonidine. It might reduce high heart rate and improve symptoms during standing. This study should help clinicians and the growing population of patients with POTS gain a better understanding of this disorder and find more personalized treatment.
Read the detailed description
Patients with POTS experience symptoms and an increase in heart rate≥30 beats/min with standing in the absence of orthostatic hypotension. As a result of considerable functional impairment, individuals with POTS are often unable to attend school or work. There is agreement that POTS is a heterogeneous disorder with multiple overlapping pathophysiologies proposed to underlie the clinical phenotype of patients. It would be important to define the underlying pathophysiological mechanisms in an individual patient to design optimal therapy. Our overarching hypothesis is that there is a subset of POTS patients (psPOTS) with a central sympathetic activation as the primary pathophysiology. We have characterized these patients by an increase in muscle sympathetic nerve activity (MSNA, a reflection of central sympathetic outflow) even at rest. In this project, we will focus on the role of primary sympathetic activation in the pathogenesis of POTS. Direct neural recordings of sympathetic activity, central sympathetic inhibition and extensive autonomic phenotyping will enable us to identify and correct the primary pathophysiology to optimally benefit psPOTS patients. This is a mechanistic study, designed to assess the effects of 4 weeks of central sympatholysis with moxonidine on orthostatic tachycardia and symptoms (Specific Aim 1), hypovolemia (Specific Aim 2) and central and peripheral baroreflex properties (Specific Aim 3) in a randomized, crossover design with POTS patients having elevated resting sympathetic nerve activity.
- Conditions
- Postural Tachycardia Syndrome
- Being tested
- Placebo oral tablet, Moxonidine Pill
- Keywords
- postural tachycardia syndrome, hyperadrenergic, moxonidine, sympatholytic, orthostatic symptoms, POTS
- Medical subject headings
- Postural Orthostatic Tachycardia Syndrome
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Placebo oral tabletDrug
Also called inactive pill
Placebo pill identical to moxonidine administered for 4 weeks
Moxonidine PillDrug
Also called Physiotens
Moxonidine pill administered for 4 weeks
| Study group | Role | What they receive |
|---|---|---|
| Moxonidine then Placebo | Experimental | After screening/baseline evaluations, patients will be discharged home on moxonidine 0.2-0.4 mg/day PO. After two weeks, the patients will be re-admitted for study testing while on moxonidine. At completion of this testing, patients will start taking matching placebo once daily PO to be continued at home. After two, the patients will be re-admitted for study testing while on placebo. Receives: Drug: Placebo oral tablet; Drug: Moxonidine Pill |
| Placebo then Moxonidine | Experimental | After screening/baseline evaluations, patients will be discharged home on placebo identical to moxonidine once daily PO. After two weeks, the patients will be re-admitted for study testing while on placebo. At completion of this testing, patients will start taking moxonidine 0.2-0.4 mg/day PO to be continued at home. After two weeks, the patients will be re-admitted for study testing while on moxonidine. Receives: Drug: Placebo oral tablet; Drug: Moxonidine Pill |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Orthostatic Symptom Burden [delta (delta VOSS)]
VOSS is a validated questionnaire that consists of 9 items: mental clouding, blurred vision, shortness of breath, rapid heartbeat, tremulousness, chest discomfort, headache, lightheadedness, and nausea. Each item is scored on a 0 to 10 scale (with 0 reflecting absence of symptoms), and the change of the total scores (range: 0-90) from supine to upright postures (delta VOSS) will be used as a measure of orthostatic symptom burden. The primary outcome measure will be the difference in orthostatic symptom burden [delta (delta VOSS)] following 4 weeks of placebo vs. moxonidine treatment.
Measured: after 30 min supine to after 15 min of 60 degrees upright tilt (delta VOSS), 2-3 hours after a dose of the treatment assigned for the previous period.
Secondary outcomes (1)
Change in Orthostatic Change in Heart Rate [delta (delta HR)]
Difference in heart rate change from supine to upright postures (delta HR) following 4 weeks of placebo vs. moxonidine treatment [delta (delta HR)].
Measured: after 30 min supine to after 15 min of 60 degrees upright tilt (delta HR), 2-3 hours after a dose of the treatment assigned for the previous period.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Oct 2019
- Study start31 Aug 2021
- Primary completion31 Dec 2025
- Study completion31 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Postural Tachycardia SyndromeStudies of the same condition, open and under way.
- More trials run by Vanderbilt University Medical CenterThe 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
- Early Phase 1
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- randomized, double blind, crossover design
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 48 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Vanderbilt University Medical Center
- Sponsor type
- University, hospital or other
- Collaborators
- National Heart, Lung, and Blood Institute (NHLBI)
- Responsible party
- Principal investigator, Andre' Diedrich, Vanderbilt University Medical Center
- Investigators
- André Diedrich, MD, PhD, Principal investigator, Vanderbilt University Medical Center
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04140721
- Sponsor's protocol ID
- VANDERBILT_IRB_191749
- Other IDs
- R01HL142583
- Status last verified
- Mar 2026
- First submitted
- 24 Oct 2019
- Last updated
- 27 Mar 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 27 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Autonomic Determinants of Postural Tachycardia Syndrome (Chronic Pilot Study 2)
- ClinicalTrials.gov ID
- NCT04140721
- Acronym / sponsor ID
- VANDERBILT_IRB_191749
- Conditions
- Postural Tachycardia Syndrome
- Keywords
- postural tachycardia syndrome, hyperadrenergic, moxonidine, sympatholytic, orthostatic symptoms, POTS
- Phase
- Early Phase 1
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 48 participants (estimated)
- Lead sponsor
- Vanderbilt University Medical CenterUniversity, hospital or other
- Collaborators
- National Heart, Lung, and Blood Institute (NHLBI)
- Study start
- 31 Aug 2021 (actual)
- Primary completion
- 31 Dec 2025 (actual)
- Study completion
- 31 Dec 2026 (estimated)
- First posted
- 28 Oct 2019 (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.
Postural tachycardia syndrome (POTS) is a relatively common condition affecting mostly otherwise healthy young women. These patients have high heart rate and disabling symptoms during standing. Quality of life may be poor. The sympathetic nerves in the autonomic nervous system help to maintain normal blood pressures and heart rates during activities of daily life.
The purpose of this study is to determine the importance of sympathetic activation as a cause of orthostatic symptoms. The investigators will assess the effects of a blood pressure medication (Moxonidine) on the symptoms during standing. Moxonidine lowers sympathetic activity. The investigators believe patients with high resting sympathetic activity might benefit from Moxonidine. It might reduce high heart rate and improve symptoms during standing. This study should help clinicians and the growing population of patients with POTS gain a better understanding of this disorder and find more personalized treatment.
Detailed description
Patients with POTS experience symptoms and an increase in heart rate≥30 beats/min with standing in the absence of orthostatic hypotension. As a result of considerable functional impairment, individuals with POTS are often unable to attend school or work. There is agreement that POTS is a heterogeneous disorder with multiple overlapping pathophysiologies proposed to underlie the clinical phenotype of patients. It would be important to define the underlying pathophysiological mechanisms in an individual patient to design optimal therapy. Our overarching hypothesis is that there is a subset of POTS patients (psPOTS) with a central sympathetic activation as the primary pathophysiology. We have characterized these patients by an increase in muscle sympathetic nerve activity (MSNA, a reflection of central sympathetic outflow) even at rest. In this project, we will focus on the role of primary sympathetic activation in the pathogenesis of POTS. Direct neural recordings of sympathetic activity, central sympathetic inhibition and extensive autonomic phenotyping will enable us to identify and correct the primary pathophysiology to optimally benefit psPOTS patients. This is a mechanistic study, designed to assess the effects of 4 weeks of central sympatholysis with moxonidine on orthostatic tachycardia and symptoms (Specific Aim 1), hypovolemia (Specific Aim 2) and central and peripheral baroreflex properties (Specific Aim 3) in a randomized, crossover design with POTS patients having elevated resting sympathetic nerve activity.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
- Model description
- randomized, double blind, crossover design
| Arm | Type | Receives |
|---|---|---|
| Moxonidine then Placebo | Experimental | Drug: Placebo oral tablet, Drug: Moxonidine PillAfter screening/baseline evaluations, patients will be discharged home on moxonidine 0.2-0.4 mg/day PO. After two weeks, the patients will be re-admitted for study testing while on moxonidine. At completion of this testing, patients will start taking matching placebo once daily PO to be continued at home. After two, the patients will be re-admitted for study testing while on placebo. |
| Placebo then Moxonidine | Experimental | Drug: Placebo oral tablet, Drug: Moxonidine PillAfter screening/baseline evaluations, patients will be discharged home on placebo identical to moxonidine once daily PO. After two weeks, the patients will be re-admitted for study testing while on placebo. At completion of this testing, patients will start taking moxonidine 0.2-0.4 mg/day PO to be continued at home. After two weeks, the patients will be re-admitted for study testing while on moxonidine. |
Who may qualify
- Ages
- 18 to 55 years
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (7 listed)
- meets criteria for postural tachycardia syndrome (POTS)
- in the follicular phase of the menstrual cycle (days 5-13 of a 28-day cycle)
- POTS with primary central sympathetic activation (psPOTS) as defined as having resting MSNA ≥ 25 bursts/min
- able and willing to provide informed consent.
Key exclusion criteria (10 listed)
- pregnancy,
- smoker,
- BMI>30 kg/m2,
- deconditioned status (if available VO2max<80% of predicted)
- unable to withdraw from medications known to affect autonomic function, blood pressure or blood volume
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 |
|---|---|---|
| Placebo oral tabletAlso: inactive pillPlacebo pill identical to moxonidine administered for 4 weeks | Drug | Moxonidine then Placebo, Placebo then Moxonidine |
| Moxonidine PillAlso: PhysiotensMoxonidine pill administered for 4 weeks | Drug | Moxonidine then Placebo, Placebo then Moxonidine |
Primary outcome
Change in Orthostatic Symptom Burden [delta (delta VOSS)]
Time frame: after 30 min supine to after 15 min of 60 degrees upright tilt (delta VOSS), 2-3 hours after a dose of the treatment assigned for the previous period.
VOSS is a validated questionnaire that consists of 9 items: mental clouding, blurred vision, shortness of breath, rapid heartbeat, tremulousness, chest discomfort, headache, lightheadedness, and nausea. Each item is scored on a 0 to 10 scale (with 0 reflecting absence of symptoms), and the change of the total scores (range: 0-90) from supine to upright postures (delta VOSS) will be used as a measure of orthostatic symptom burden. The primary outcome measure will be the difference in orthostatic symptom burden [delta (delta VOSS)] following 4 weeks of placebo vs. moxonidine treatment.
1 secondary outcome
Change in Orthostatic Change in Heart Rate [delta (delta HR)]
Time frame: after 30 min supine to after 15 min of 60 degrees upright tilt (delta HR), 2-3 hours after a dose of the treatment assigned for the previous period.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 27 Mar 2026.
- Individual participant dataSharing planned: No
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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.
André Diedrich, MD, PhD principal investigator
Vanderbilt University Medical Center
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Early Phase 1 study testing Moxonidine Pill in people with Postural Tachycardia Syndrome, run by Vanderbilt University Medical Center 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 7 inclusion and 10 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: under way, not looking for participants, as of the sponsor's last update on 27 Mar 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?
Early Phase 1 (sometimes called Phase 0) studies give a very small amount of a treatment to a few people, mainly to see how the body handles it.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
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?
Change in Orthostatic Symptom Burden [delta (delta VOSS)] (time frame: after 30 min supine to after 15 min of 60 degrees upright tilt (delta VOSS), 2-3 hours after a dose of the treatment assigned for the previous period.). 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 27 Mar 2026.