← Back to Search

Alpha Blocker

Sympathetic Vasoconstriction Blockade for Obesity

Nashville, TN
Phase 1
Waitlist Available
Research Sponsored by Vanderbilt University Medical Center
Eligibility Criteria Checklist
Specific guidelines that determine who can or cannot participate in a clinical trial
Must have
Insulin resistance defined as homeostasis model assessment 2 insulin resistance (HOMA2-IR) score >1.6 (never diagnosed or treated type 2 diabetic), or being a well-controlled type 2 diabetic on metformin only.
Insulin resistance defined as homeostasis model assessment 2 insulin resistance (HOMA2-IR) score >1.6 (never diagnosed or treated type 2 diabetic), or being a well-controlled type 2 diabetic on metformin only
Must not have
Cardiovascular disease other than hypertension such as myocardial infarction within 6 months prior to enrollment, presence of angina pectoris, significant arrhythmia, congestive heart failure (LV hypertrophy acceptable), deep vein thrombosis, pulmonary embolism, second or third-degree heart block, mitral valve stenosis, aortic stenosis, or hypertrophic cardiomyopathy
Evidence of type I diabetes
Timeline
Screening 3 weeks
Treatment Varies
Follow Up before clamp and 15 minutes after clamp

Summary

This trial is testing whether removing sympathetic vasoconstriction can improve insulin-mediated vasodilation and sensitivity to insulin-mediated glucose uptake.

See full description
Who is the study for?
This trial is for adults aged 18-60 with obesity (BMI between 30-40) and insulin resistance, but not severe diabetes. Participants can be well-controlled type 2 diabetics on metformin. Exclusions include those on anticoagulants, with morbid obesity or cardiovascular disease, drug abuse history, heavy smokers, or certain medication users.Check my eligibility
What is being tested?
The study tests if blocking sympathetic vasoconstriction improves insulin-induced vasodilation and glucose uptake in obese individuals. It involves administering Phentolamine (blocks adrenaline effects), Saline (a placebo), and Sodium Nitroprusside (enhances blood flow).See study design
What are the potential side effects?
Potential side effects may include low blood pressure, dizziness, headache from Phentolamine; irritation at the infusion site from Saline; and possible rapid heartbeat or changes in blood oxygen levels from Sodium Nitroprusside.

Eligibility Criteria

Inclusion Criteria

You may be eligible if you check “Yes” for the criteria below
Select...
I have insulin resistance or am a well-controlled type 2 diabetic on metformin.
 show original
Select...
I have insulin resistance or am a well-controlled type 2 diabetic on metformin.
 show original
Select...
My BMI is between 30 and 40.
 show original

Exclusion Criteria

You may be eligible for the trial if you check “No” for criteria below:
Select...
I do not have serious heart conditions like recent heart attacks or severe heart failure.
 show original
Select...
I have been diagnosed with type 1 diabetes.
 show original
Select...
I have a history of immune or blood disorders.
 show original
Select...
My liver tests (AST or ALT) are higher than normal.
 show original
Select...
I have been on long-term steroid treatment for over a week in the past month.
 show original
Select...
My BMI is over 40.
 show original
Select...
I am a current smoker or have a history of heavy smoking.
 show original
Select...
I am unable to understand or decide about participating in this study.
 show original
Select...
I am currently taking medication for depression or anxiety.
 show original
Select...
I am currently taking blood thinners.
 show original
Select...
I have had a serious stroke or similar brain issue.
 show original
Select...
I am taking medication for erectile dysfunction.
 show original
Select...
My kidney function is impaired with high creatinine levels.
 show original

Timeline

Screening ~ 3 weeks
Treatment ~ Varies
Follow Up ~before clamp and 15 minutes after clamp
This trial's timeline: 3 weeks for screening, Varies for treatment, and before clamp and 15 minutes after clamp for reporting.

Treatment Details

Study Objectives

Study objectives can provide a clearer picture of what you can expect from a treatment.
Primary study objectives
Contrast Enhanced-Ultrasonography (CEU)

Trial Design

3Treatment groups
Experimental Treatment
Active Control
Placebo Group
Group I: Blocked DayExperimental Treatment1 Intervention
Phentolamine
Group II: Vasodilator ComparisonActive Control1 Intervention
Sodium Nitroprusside
Group III: Intact DayPlacebo Group1 Intervention
Saline

Find a Location

Closest Location:Autonomic Dysfunction Center· Nashville, TN

Logistics

Participation is compensated

You will be compensated for participating in this trial.

Who is running the clinical trial?

Vanderbilt University Medical CenterLead Sponsor
919 Previous Clinical Trials
938,719 Total Patients Enrolled
10 Trials studying Insulin Resistance
824 Patients Enrolled for Insulin Resistance

Media Library

Insulin Resistance Research Study Groups: Intact Day, Blocked Day, Vasodilator Comparison
Insulin Resistance Clinical Trial 2023: Phentolamine Highlights & Side Effects. Trial Name: NCT03318094 — Phase 1
Phentolamine (Alpha Blocker) 2023 Treatment Timeline for Medical Study. Trial Name: NCT03318094 — Phase 1
Insulin Resistance Patient Testimony for trial: Trial Name: NCT03318094 — Phase 1
~3 spots leftby Nov 2025
Unbiased ResultsWe believe in providing patients with all the options.
Your Data Stays Your DataWe only share your information with the clinical trials you're trying to access.
Verified Trials OnlyAll of our trials are run by licensed doctors, researchers, and healthcare companies.
Back to top