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A Trial of Tadalafil and Glycemic Traits

This study has been completed.
Information provided by (Responsible Party):
Thomas J. Wang, MD, Massachusetts General Hospital Identifier:
First received: August 3, 2011
Last updated: February 5, 2014
Last verified: February 2014
The purpose of this study is to find out if tadalafil can help overweight and obese people metabolize blood sugar more efficiently. The investigators also want to find out if 20 mg/day of tadalafil for 3 months is safe to take without causing too many side effects. The investigators are plan to enroll 100 subjects at Massachusetts General Hospital (MGH).

Condition Intervention Phase
Cardiovascular Disease
Insulin Resistance
Glucose Intolerance
Drug: Tadalafil
Drug: Placebo
Phase 3

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, Investigator)
Primary Purpose: Treatment
Official Title: Phase 3 Randomized Trial of Tadalafil and Glycemic Traits

Resource links provided by NLM:

Further study details as provided by Massachusetts General Hospital:

Primary Outcome Measures:
  • Insulin Resistance, as measured by HOMA-IR [ Time Frame: 3 months ] [ Designated as safety issue: No ]
    The primary endpoint is defined as the change in insulin resistance (as measured by HOMA-IR).

Secondary Outcome Measures:
  • Insulin Sensitivity, as measured by the Matsuda index [ Time Frame: 3 months ] [ Designated as safety issue: No ]
    Change in insulin sensitivity (as measured by the Matsuda index).

  • Endothelial function [ Time Frame: 3 months ] [ Designated as safety issue: No ]
    reactive hyperemia index, using EndoPAT device

  • Insulin sensitivity, as measured by the Stumvoll sensitivity index [ Time Frame: 3 months ] [ Designated as safety issue: No ]
    Change in insulin sensitivity (as measured by the Stumvoll index)

  • Pancreatic beta-cell function, as measured by HOMA-B [ Time Frame: 3 months ] [ Designated as safety issue: No ]
    Change in pancreatic beta-cell function

  • Insulin release, as measured by the insulinogenic index [ Time Frame: 3 months ] [ Designated as safety issue: No ]
    Change in insulin release

  • Composite of insulin resistance and sensitivity, as measured by the oral disposition index [ Time Frame: 3 months ] [ Designated as safety issue: No ]
    Change in composite of insulin resistance and sensitivity

  • Arterial stiffness, as measured by applanation tonometry [ Time Frame: 3 months ] [ Designated as safety issue: No ]
    Change in arterial stiffness

Enrollment: 63
Study Start Date: August 2011
Study Completion Date: March 2013
Primary Completion Date: March 2013 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: Tadalafil
20 mg Tadalafil tablet taken by mouth once a day for 3 months
Drug: Tadalafil
20 mg Tadalafil taken once a day for 3 months
Other Name: Adcirca, Cialis
Placebo Comparator: Placebo
Placebo tablet taken by mouth once a day for 3 months
Drug: Placebo
Placebo tablet taken by mouth once a day for 3 months
Other Name: Sugar pill

Detailed Description:

This study is examining changes in insulin resistance and glucose tolerance following 3 months of treatment with oral, once daily tadalafil.

The investigators primary hypotheses are that measurable decreases in insulin resistance (as measured by HOMA-IR) and increases in insulin sensitivity (as measured by the Matsuda index) will occur following 3 months of treatment with oral tadalafil 20 mg daily compared to placebo.

The investigators secondary hypotheses are that improvements in average glycemia (as measured by hemoglobin A1C), pancreatic beta cell function (as measured by the oral disposition index), and body composition (including weight, waist circumference, body mass index, and waist-hip ratio) will occur as a result of tadalafil-mediated changes in the cGMP pathway.


Ages Eligible for Study:   18 Years to 50 Years   (Adult)
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Age > 18 years and < 50 years
  • BMI > 30 kg/m2
  • Fasting insulin > 10 uU/mL

Exclusion Criteria:

  • Systolic blood pressure (SBP) < 100, > 150 mmHg
  • Current anti-hypertensive medication use, including diuretics
  • Current use of organic nitrates
  • Current use of PDE-5 inhibitors (sildenafil, tadalafil, vardenafil)
  • History of reaction to PDE-5 inhibitors
  • Known HIV infection
  • Use of medications that strongly alter CYP3A4 activity
  • History of myocardial infarction, angina, uncontrolled cardiac arrhythmia, stroke, transient ischemic attack, or seizure
  • Known non-arteritic ischemic optic retinopathy (NAIOR)
  • History of hearing loss
  • Estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m2 by the modified diet in renal disease (MDRD) equation
  • Hepatic transaminase (AST and ALT) levels greater than three times the upper limit of normal
  • Known pregnancy or those unwilling to avoid pregnancy during the course of the study
  • History of priapism
  • Use in excess of four alcoholic drinks daily
  • History of diabetes mellitus or use of anti-diabetic medications
  • Known anemia (men, Hct < 38% and women, Hct < 36%)
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT01444651

United States, Massachusetts
Massachusetts General Hospital
Boston, Massachusetts, United States
Sponsors and Collaborators
Thomas J. Wang, MD
Principal Investigator: Thomas J Wang, MD Massachusetts General Hospital
  More Information

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Thomas J. Wang, MD, Associate Professor of Medicine, Harvard Medical School, Massachusetts General Hospital Identifier: NCT01444651     History of Changes
Other Study ID Numbers: 2010P-001519 
Study First Received: August 3, 2011
Last Updated: February 5, 2014
Health Authority: United States: Institutional Review Board

Keywords provided by Massachusetts General Hospital:
Phosphodiesterase 5 Inhibitors
Cyclic Guanylyl Monophosphate Pathway
Pharmacologic Actions
Vasodilator Agents
Cardiovascular Agents
Glycemic Traits
Insulin Resistance
Glucose Metabolism

Additional relevant MeSH terms:
Cardiovascular Diseases
Insulin Resistance
Glucose Intolerance
Glucose Metabolism Disorders
Metabolic Diseases
Phosphodiesterase 5 Inhibitors
Vasodilator Agents
Phosphodiesterase Inhibitors
Enzyme Inhibitors
Molecular Mechanisms of Pharmacological Action
Urological Agents processed this record on December 09, 2016