Does Viagra enhance insulin action in patients with prediabetes?

This study examined whether sildenafil (Viagra) treatment increases insulin production and action in patients with prediabetes. The authors concluded that sildenafil treatment enhances insulin action.

Prediabetes is a condition in which blood glucose (sugar) levels are higher than normal but not high enough to be diagnosed with type 2 diabetes (T2D).

Patients with prediabetes produce insulin but have a reduction in insulin sensitivity (ability of insulin to work in the body). It is thought that sildenafil (Viagra) may increase insulin release from the pancreas and also increase insulin sensitivity.  

Reduced kidney function in individuals with prediabetes may indicate progression to T2D. It is thought that sildenafil may also enhance kidney function in individuals with prediabetes.

This study aimed to determine whether sildenafil treatment enhances insulin secretion and sensitivity in patients with prediabetes.

This study involved 42 patients with prediabetes. Participants were divided into 2 groups. One group received 25 mg of sildenafil three times daily for 3 months. The other group received a placebo (substance with no therapeutic effect) three times daily for 3 months.

Insulin secretion and sensitivity measurements were recorded at the start and end of the study. The urine albumin-to-creatinine ratio (ACR) was also measured at the start and end of the study. A low ACR indicates better kidney function.

After 3 months, insulin sensitivity significantly increased (by 1.84 mg/kg/min) in the sildenafil group compared to the placebo group. Insulin secretion did not increase in the sildenafil group after 3 months. The ACR decreased from 12.67 ug/mg to 6.84 ug/mg in the sildenafil group. The ACR did not significantly decrease in the placebo group.

This study concluded that 3-month sildenafil treatment enhanced insulin sensitivity in patients with prediabetes.

This study did not determine whether sildenafil is effective in reversing prediabetes. In addition, it is not known whether treatment for more than 3 months is effective.