Conditions: Cardiovascular Disease Insulin Resistance Glucose Intolerance Obesity
Keywords: Tadalafil Phosphodiesterase 5 Inhibitors Cyclic Guanylyl Monophosphate Pathway Pharmacologic Actions Vasodilator Agents Cardiovascular Agents Obesity Glycemic Traits Insulin Resistance Glucose Metabolism
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 73
Healthy volunteers: yes

Brief summary:
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).

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.

Arms:
arm 1: 20 mg Tadalafil tablet taken by mouth once a day for 3 months arm 2: Placebo tablet taken by mouth once a day for 3 months

Interventions: intervention 1: Tadalafil intervention 2: Placebo
Intervention descriptions: intervention 1: 20 mg Tadalafil taken once a day for 3 months intervention 2: Placebo tablet taken by mouth once a day for 3 months

Protocol document: