Exploring the Effects of Prazosin on Basal Dopamine in Healthy Humans: A [11C]-(+)-PHNO PET Pilot Study
Trial Snapshot
- Phase
- Phase 1
- Status
- Completed
- Enrollment
- 20
- Locations
- 1
- Primary Endpoint
- Changes in [11C]-(+)-PHNO Binding (Measured as Binding Potential) in Dorsal Caudate (DC)
Study Overview
Brief Summary
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.
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 Design
- Study Type
- Interventional
- Allocation
- Na
- Intervention Model
- Single Group
- Primary Purpose
- Basic Science
- Masking
- None
Eligibility Criteria
- Ages
- 19 Years to 45 Years (Adult)
- Sex
- All
- Accepts Healthy Volunteers
- Yes
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
Arms & Interventions
Prazosin Hydrochloride
Gradual upward titration to 15mg/day (or highest dose tolerated) for approximately three weeks.
Intervention: Prazosin Hydrochloride (Drug)
Outcomes
Primary Outcomes
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
Secondary Outcomes
No secondary outcomes reported
Investigators
Bernard Le Foll
Principal Investigator
Centre for Addiction and Mental Health