Viagra ups insulin sensitivity in prediabetes

by Bruce Sylvester: Treatment with sildenafil, marketed as Viagra and other trade names, appears to improve insulin sensitivity in persons with prediabetes, as well as lowering a biological signal of elevated risk of kidney and heart disease. Researchers reported these findings on Nov. 18, 2015 in the Journal of Clinical Endocrinology & Metabolism.

“We need additional strategies to help slow the progression from prediabetes to diabetes,” said investigator Nancy Brown, MD, of Vanderbilt University School of Medicine in Nashville, TN. “Weight loss and exercise regimens can be difficult to maintain, and some current medications have been limited by concerns about adverse effects. Sildenafil and related drugs could offer a potential avenue for addressing the rising number of diabetes diagnoses.”

As background, the authors noted that over 29 million Americans have diabetes. Among all adults, 3 in 10 have prediabetes. Without intervention, up to 30 percent of those with prediabetes are likely to develop Type 2 diabetes within five years.

The researchers enrolled 51 overweight subjects diagnosed with prediabetes.

They randomized the subjects to treatment for 3 months with sildenafil 25 mg three times a day or matching placebo.

“The objective was to test the hypothesis that chronic phosphodiesterase 5 inhibition with sildenafil improves insulin sensitivity and secretion without diminishing fibrinolytic function. The primary outcomes of the study were insulin sensitivity and glucose-stimulated insulin secretion,” the authors wrote.

Forty-two subjects, 21 in each group, completed treatment.

At 3 months, the insulin sensitivity index was significantly greater in the sildenafil group compared to the placebo group (p = .049), after adjusting for baseline insulin sensitivity and body mass.

Notably, the investigators found no effect of 3-month treatment with sildenafil on acute or late-phase glucose-stimulated insulin secretion (p > .30).

Sildenafil lowered plasminogen activator inhibitor-1 (p = .01), and did not change tissue-plasminogen activator.

In contrast to placebo, sildenafil also decreased the urine albumin-to-creatinine ratio from 12.67 ± 14.67 to 6.84 ± 4.86 μg/mg Cr. This effect persisted for 3 months after sildenafil treatment ended.

“Three-month phosphodiesterase 5 inhibition enhances insulin sensitivity and improves markers of endothelial function,” the authors concluded.