Does Tadalafil Increase The Uptake of Finasteride into Prostate Tissue? A Biochemical and Histological Evaluation in Rats.

Abstract

To histopathologically and biochemically evaluate the hypothesis that tadalafil increases the uptake of a second medication into the prostate tissue by increasing the blood supply in the prostate. Forty 12-week-old Sprague Dawley male rats were equally divided into 5 groups and were administered drugs orally as follows: Group 1 - no drugs, Group 2 - 10 days of finasteride, Group 3 - 10 days of finasteride + tadalafil, Group 4 - 30 days of finasteride, and Group 5 - 30 days of finasteride + tadalafil. At the end of 10 days of drug administration in Group1, 2, and 3, and at the end of 30 days of drug administration in Group 4 and 5,blood samples were collected from rats and analyzed for serum androgen levels. In addition, prostate tissues were removed for histological examination. The mean DHT level as well as the minimum and maximum epithelial thicknesses in Group 3 were lower than those in Group 2. However, there was no statistical significant difference (P = 0.989, P = 0.176, and P = 0.070, respectively). The mean DHT level as well as the minimum and maximum epithelial thicknesses in Group 5 were lower than those in Group 4. However, there was no statistical significant difference (P = 0.984, P = 0.147, and P= 0.478, respectively). The mean minimum and maximum epithelial thicknesses in Group 3 and Group 4 were not statistically different (P = 0.488 and P = 0.996, respectively). The similarity of the mean minimum and maximum epithelial thickness in Group 3 and Group 4 may be indicate that the combination therapy provides an early histological effect. However, the fact that there was no statistical significant difference between Group 2 and Group 3, and between Group 4 and Group 5, in terms of the mean DHT level and minimum-maximum epithelial thicknesses suggests that longer term studies with more rats are necessary to test the validity of our hypothesis.