Effects of Systemic Tadalafil on Skin Flap Survival in Rats

Objective: Phosphodiesterase-5 inhibitors, used to increase penile blood flow in erectile dysfunction patients, have recently been postulated to increase blood flow and flap survival in cutaneous flaps based on random blood supply. This study aims to investigate the phosphodiesterase-5 inhibitor tadalafil, administered orally, on random flap survival. Methods: Modified McFarlane flaps measuring 8 cm × 2.5 cm were raised on the backs of 37 male Sprague-Dawley rats. Rats received were divided into a control group, a low-dose group (10 mg/kg tadalafil), and a high-dose group (20 mg/kg tadalafil). Treatment doses were administered once preoperatively and every 24 hours postoperatively for a total of 7 doses. On postoperative day 7 and 14, the area of flap survival was calculated and compared. Results: All rats survived and thrived throughout the experimental period. Control group rats showed an average flap survival of 77% ± 11% at 7 days and 77% ± 9% at 14 days. Low-dose-group rats showed an average flap survival of 82% ± 10% at 7 days (P=0.21), and 81% ± 12% at 14 days (P=0.41). High-dose group rats showed an average flap survival of 81% ± 11% at 7 days (P = 0.45) and 80% ± 12% at 14 days (P = 0.53). Statistical analysis was performed using the Mann-Whitney test. Conclusions: Our results indicate a trend toward increased random-pattern flap survival with both high- and low-dose oral tadalafil in a rat model. Because this trend did not achieve statistical significance, further studies are warranted.