Effects of Tadalafil on the volume, motility, and concentration of the semen, and the duration of erection in male dogs

The use of phosphodiesterase-5 inhibitors (tadalafil) has become the first-line treatment of erectile dysfunction nowadays. However, there is not any available study about its effect on the erection and spermatozoa characters of dogs. In this study in order to explore the effects of Tadalafil on the erection and ejaculation characters of male dogs, 20 male dogs were prepared. At first, Semen samples were collected by masturbation in all dogs, and they were encountered as the control group. The dogs fed Tadalafil tablets (20 mg, Farabi Co., Iran) after 6 to 10 days, and the new semen samples were collected after 45 minutes of the treatment. At this stage, the animals and their semen samples were encountered as the test group. All semen samples immediately sent to a laboratory in ice container. Blood pressures were examined for all dogs in the control and the test groups immediately after the semen collection. The semen indexes were analyzed with a CASA system in Tehran-Royan Institute. Results showed that the major characters such as the duration of erection (7.5 vs. 13.75 min), the volume (4.75 vs. 5.5 ml), and the concentration (231×106 vs. 250×106 cells/ml) of samples, and the rate of motile (%85.55 vs. %92) spermatozoa were significantly increased in Tadalafil treated dogs. Unfortunately, systolic (143 vs. 155mmHg) and diastolic (76 vs. 80mmHg) blood pressures were too increased. It was concluded that Tadalafil had a positive effect on spermatozoa cells, and it can be used in erection failure in male dogs.