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Posttraumatic Stress DisorderPhase 3PREDICTNCT03539614

Predicting Responses to PTSD Treatment With Iris and Cardiovascular Tests

A Phase 3 study testing Prazosin in people with Posttraumatic Stress Disorder, run by VA Office of Research and Development at 1 site in United States.

Active, not recruiting

Under way, not looking for participants. Everyone needed has enrolled. The study is still running.

Official record
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Trial summary

Post-traumatic stress disorder (PTSD) affects many individuals who experience a traumatic event. There are a variety of treatment options for PTSD, including psychotherapy (talk therapy) options, as well as medications, such as the drug prazosin. Read more about this study

Who is it for?
Ages 21 to 75 years
Conditions the study is for
Posttraumatic Stress Disorder
What is being tested?
Prazosin
Type of treatment
Pill or oral medicine
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
87 participants
Where
1 siteUnited States
Study dates
4 Jun 2018to 31 Dec 2026
Phase
Phase 3
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 21 to 75 years
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Veteran of the U.S. Armed Forces
  • Current diagnosis of PTSD (as documented in clinical chart and/or per participant report; a rule out diagnosis from a VA provider accompanied by a referral to the VA PTSD Outpatient Clinic (POC) will also be considered sufficient for inclusion)
  • Woman of childbearing potential must agree to abstain from sexual relations that could result in pregnancy or use an effective method of birth control acceptable to both participant and study clinician during the study. Men are not required to use contraception during the study.

Who cannot join

  • Psychiatric:
  • Any known diagnosis of a primary psychotic or major neurocognitive disorder, including schizophrenia, brief psychotic disorder, or Alzheimer's or other dementia, as well as bipolar type I
  • Severe psychiatric instability or severe situational life crises, including evidence of being actively suicidal or homicidal, or any behavior which poses an immediate danger to participant or others.
  • Note: Nonsuicidal depression comorbid with PTSD will not be exclusionary. Participants may continue in any concurrent psychotherapy or pharmacotherapy in which they are participating, other than pharmacotherapeutic agents specifically listed above. Participants with active suicidal ideation or with depression severe enough to require psychiatric hospitalization will be excluded.
  • Medical:
  • Significant bilateral visual loss (would preclude performing the PLR measurements)
Show all 15Show fewer
  • Current pregnancy or lactation
  • Allergy or previous adverse reaction to prazosin or other alpha-1 antagonist
  • Acute or unstable chronic medical illness, including unstable angina, recent myocardial infarction (within 6 months), congestive heart failure, preexisting hypotension (systolic <110) or orthostatic hypotension (systolic drop > 20mmHg after two minutes standing or any drop accompanied by dizziness); autoimmune disorders; insulin-dependent diabetes
  • Chronic renal or hepatic failure, acute pancreatitis, Meniere's disease, benign positional vertigo, or narcolepsy
  • Medication / treatment:
  • Any use within the 7 days prior to baseline of prazosin, doxazosin, clonidine, guanfacine, trazodone, or nonbenzodiazepine hypnotics, and/or unwillingness to avoid these medications for the duration of the study
  • Use of avanafil (Stendra), sildenafil (Viagra), tadalafil (Cialis), and vardenafil (Levitra) will be not be permitted during the study dose titration period because of increased risk of hypotension in combination with alpha-1 blockers, but will be allowed at 1/2 the usual starting dose following dose titration
  • Current use of nitrates, or of alternative medications or supplements with significant vasodilatory properties (e.g., nitrate containing supplements)
  • Participants may also be excluded at the discretion of PI or study clinicians if they appear to be unsuitable for this research study for a reason not detailed here.

Trial locations and contacts

1 site in 1 country.

United States1 site
  • VA Puget Sound Health Care System Seattle Division, Seattle, WA

    Seattle, Washington, 98108-1532

Other trials in United States

About this study

Official title: Noradrenergic Biomarkers in PTSD: Precision Medicine & Mechanisms

Post-traumatic stress disorder (PTSD) affects many individuals who experience a traumatic event. There are a variety of treatment options for PTSD, including psychotherapy (talk therapy) options, as well as medications, such as the drug prazosin. Each of the treatment options available is effective at significantly reducing the symptoms of PTSD in some, but not all, individuals with PTSD. However, investigators are not yet able to predict in advance who is likely to respond to which of the available treatments. Neither are the investigators able to explain what changes in the brain after exposure to a traumatic stressors, and why it results in persistent symptoms of PTSD for some people, but not for others.

In this study, the investigators are testing two things: First, is testing whether two simple, easy tests of how an individual's blood pressure changes with standing and how an individual's eye reacts to a pulse of light may be able to predict whether that person is likely to respond to the medication prazosin for PTSD. Second, is testing whether those who have been exposed to a traumatic stress show differences in how their body regulates the response to the stress-signal noradrenaline.

Read the detailed description

In this study, individuals will undergo an assessment that includes taking a history of their previous exposure to traumatic events, an assessment of current mental health symptoms including those associated with PTSD, and an assessment of physiologic measures, such as blood pressure and pupillary responses to light. For individuals who have current symptoms of PTSD and for whom use of the medication prazosin is a reasonable and safe option, a second phase of the study will be offered. In this second phase, how the individual's PTSD symptoms change when taking prazosin will be assessed. In addition, to test whether any changes are related to the prazosin itself or are part of a placebo effect, the individual will be randomly assigned to periods where he or she is taking a pill that looks like prazosin but is actual placebo (a pill with no active ingredient), and periods where he or she is taking a pill that looks the same but this time is actual prazosin.

Of note, there is also an additional observational portion of the protocol that is not a direct part of the interventional trial described here, but data from which will be used to help to interpret the data from the interventional trial; because reporting of study results depends on both portiosn, the study completion date estimates/reports will reflect when both the interventional and observational trial components are complete.

Being tested
Prazosin, Placebo
Keywords
Prazosin, Nightmares, N-of-1
Medical subject headings
Stress Disorders, Post-Traumatic

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • PrazosinDrug

    Also called Minipress

    This is an antagonist of the alpha1 receptor for noradrenaline. It is FDA approved for the treatment of hypertension, and has also been used for benign prostatic hypertrophy (BPH). Most recently, it has been found to be helpful for symptoms of PTSD in some but not all participants.

  • PlaceboDrug

    This is a capsule containing an inert substance, in order to provide blinding to participants and study staff of when participants are on active medication and when they are not during the later portions of the trial.

Study groups in NCT03539614
Study groupRoleWhat they receive
Open label, blinded discontinuation, prazosin, placeboExperimentalAll participants in this study will begin with 8 weeks of active treatment (prazosin), followed by a 4 week "blinded discontinuation" block where they will take a capsule that will start out as active treatment (prazosin), but will at some point change to placebo. Following these phases of the study, participants will be randomized to two arms. In this first arm, participants will spend 4 weeks on active treatment (prazosin), followed by 4 weeks on placebo.
Receives: Drug: Prazosin; Drug: Placebo
Open label, blinded discontinuation, placebo, prazosinExperimentalAll participants in this study will begin with 8 weeks of active treatment (prazosin), followed by a 4 week "blinded discontinuation" block where they will take a capsule that will start out as active treatment (prazosin), but will at some point change to placebo. Following these phases of the study, participants will be randomized to two arms. In this second arm, participants will spend 4 weeks on placebo, followed by 4 weeks on active treatment (prazosin).
Receives: Drug: Prazosin; Drug: Placebo

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Change in total PTSD Checklist for DSM 5 (PCL5) score

    The PTSD Checklist for Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM 5) is a self-reported rating scale where an individual rates the severity of each symptom of PTSD on a Likert scale. The ratings on individual items are summed to create a total score, which ranges from 0 to 80, with higher scores indicating more symptoms. The relationship between changes in participants' total PCL scores at different time points and prazosin exposure - and whether this relationship is moderated by baseline biomarker values - will be analyzed using a linear mixed effects model.

    Measured: The PCL5 total score is assessed at baseline, during each stage of the study, and at the endpoint of the study. Thus, measurements will be scheduled to occur at the following time points, relative to the baseline visit: 0, 4, 8, 9-12, 16, and 20 weeks

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted29 May 2018
  2. Study start4 Jun 2018
  3. Primary completion1 Jan 2026
  4. Study completion31 Dec 2026 (estimated)

Resources

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 3
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Crossover
Model description
This study is a modified cross-over study, also called an aggregated N-of-1 study. Each participant who meets criteria for participation in and completes the treatment portion of the study will spend time on open-label prazosin, blinded prazosin, and placebo.
Masking
Triple blind
Who is masked
Participant, Care provider, Outcomes assessor
Enrolment
87 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT03539614
Sponsor's protocol ID
MHBB-003-17F
Other IDs
1IK2CX001774-01
Acronym
PREDICT
Status last verified
Aug 2026
First submitted
2 May 2018
Last updated
14 Aug 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
No

Questions about this trial

What is this clinical trial studying?

A Phase 3 study testing Prazosin in people with Posttraumatic Stress Disorder, run by VA Office of Research and Development 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 15 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 14 Aug 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 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.

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 total PTSD Checklist for DSM 5 (PCL5) score (time frame: The PCL5 total score is assessed at baseline, during each stage of the study, and at the endpoint of the study. Thus, measurements will be scheduled to occur at the following time points, relative to the baseline visit: 0, 4, 8, 9-12, 16, and 20 weeks). 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 14 Aug 2026.

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