Effect of tadalafil administration on insulin secretion and insulin sensitivity in obese men

Aim: To evaluate the effect of tadalafil administration on insulin secretion and insulin sensitivity in obese men without diabetes. Methods: A randomized, double-blind, placebo-controlled clinical trial was carried out in obese male patients between 30 and 50years of age. Eighteen subjects were randomly assigned to two groups of nine patients each. During a 28-day period, subjects received 5mg orally of tadalafil or placebo each night. Patients were evaluated before and after the intervention. Total insulin secretion and first phase of insulin secretion were calculated by insulinogenic index and Stumvoll index, respectively, and insulin sensitivity was calculated using the Matsuda index. Tolerability and compliance were evaluated permanently throughout the study. Results: There were no significant differences after administration of tadalafil in total insulin secretion (0.820.45 vs. 0.61 +/- 0.27, p=0.594), first phase of insulin secretion (1332 +/- 487 vs. 1602 +/- 800, p=0.779) and insulin sensitivity (4.6 +/- 1.2 vs. 4.9 +/- 2.5, p=0.779). No significant differences were shown in other measurements. Conclusion: Tadalafil administration for 28days did not modify insulin secretion or insulin sensitivity in obese men.