The Effects of Prazosin on Dopamine in Healthy Humans: A PET Pilot Study

May 17, 2019 updated by: Bernard Le Foll, Centre for Addiction and Mental Health

Exploring the Effects of Prazosin on Basal Dopamine in Healthy Humans: A [11C]-(+)-PHNO PET Pilot Study

The purpose of this study is to find out whether short term treatment with a antihypertensive medication prazosin, can influence the levels of a dopamine in the brain. We will examine the levels of dopamine in the the brain using Positron Emission Tomography (PET) and Magnetic Resonance Imaging (MRI). We hypothesize that there will be no significant changes in dopamine levels in healthy individuals taking prazosin.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

The purpose of this study is to find out whether short term treatment with a antihypertensive medication prazosin, can influence the levels of dopamine in the brain. We will examine the levels of dopamine in the the brain using Positron Emission Tomography (PET) and Magnetic Resonance Imaging (MRI). The study will involve three PET scans and one MRI. One PET scan will be performed before the participants take prazosin for approximately three weeks, and the last two PET scans will be performed after the prazosin medication phase. We hypothesize that there will be no significant changes in dopamine levels in healthy individuals taking prazosin.

Study Type

Interventional

Enrollment (Actual)

20

Phase

  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Canada
    • Ontario
      • Toronto, Ontario, Canada, M5T 1R8
        • Centre for Addiction and Mental Health

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

15 years to 41 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Healthy males and females of any ethnic origin between 19 and 45 years old

Exclusion Criteria:

  • Use of any illicit drugs in past 3 months prior to randomization and/or have a current or past diagnosis of drug abuse/dependence (including alcohol)
  • Current or past DSM-IV diagnosis of any Axis I psychiatric disorder
  • Major psychiatric illness and/or substance dependence in first order relatives
  • Current active or past suicidal ideation
  • Baseline systolic blood pressure outside the normal range
  • Current use of medications that could interact with prazosin (e.g. beta blockers, phosphodiesterasetype 5 inhibitors, indomethacin, verapamil, modafinil, clonidine)
  • Current use or use during the previous month of medication that may affect the CNS at the time of scanning (e.g. neuroleptics, bupropion)
  • Any significant abnormalities in baseline blood results (e.g. CBC, renal and hepatic indicators) or ECG readings that would preclude the use of prazosin
  • Pregnancy, trying to become pregnant or breastfeeding
  • Presence of metal objects in the body (e.g. some artificial joints, bone pins, surgical clips, skull plate, certain part of dental braces) or implanted electronic devices (e.g. cardiac pacemaker, neurostimulator), that preclude safe MR scanning
  • Claustrophobia
  • Participation in any nuclear medicine procedures that, including the dose received during participation in this study, will bring the total radiation dose over the currently approved guideline of 20mSv in a 12-month period
  • Cardiovascular or cerebrovascular diseases
  • History of or current neurological illnesses including seizure disorders, migraine, multiple sclerosis, movement disorders, head trauma, CVA or CNS tumor
  • Abnormal body mass (defined as not within 20% of normal BMI
  • Learning disability, amnesia or other conditions that impede memory and attention

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Prazosin Hydrochloride
Gradual upward titration to 15mg/day (or highest dose tolerated) for approximately three weeks.
Drug: Prazosin Hydrochloride
Gradual upward titration to 15mg/day for approximately three weeks.
Other Names:
  • Minipress
  • Prazosin
  • Teva-Prazosin

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Changes in [11C]-(+)-PHNO Binding (Measured as Binding Potential) in Dorsal Caudate (DC)
Time Frame: 3 weeks after taking prazosin
Binding potential (an estimate of the ratio of Bmax/kd) was measured by positron emission tomography to determine if taking prazosin alters the amount of tracer bound to receptors. A negative change in binding potential means a decrease in binding potential and a positive change in binding potential represents an increase. Bmax is the total density of receptors. kd is the affinity of a drug for the target
3 weeks after taking prazosin

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Centre for Addiction and Mental Health

Collaborators

Pfizer
Ontario Lung Association

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

November 1, 2013

Primary Completion (Actual)

August 1, 2016

Study Completion (Actual)

August 1, 2016

Study Registration Dates

First Submitted

November 26, 2013

First Submitted That Met QC Criteria

November 26, 2013

First Posted (Estimate)

December 3, 2013

Study Record Updates

Last Update Posted (Actual)

May 30, 2019

Last Update Submitted That Met QC Criteria

May 17, 2019

Last Verified

May 1, 2019

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 224/2012

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

No

Study Data/Documents

  1. Publication

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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