Phosphodiesterase Type 5 Is Not Upregulated by Tadalafil in Cultures of Human Penile Cells

Long‐term incubation of human penile cells with tadalafil at concentrations above the in vitro IC50, and around the in vivo Cmax utilized in the clinical setting, did not upregulate PDE5A expression nor decrease cGMP levels. These data suggest that PDE5 upregulation is unlikely to occur in vivo on long‐term tadalafil treatment. Vernet D, Magee T, Qian A, Nolazco G, Rajfer J, and Gonzalez‐Cadavid N. Phosphodiesterase type 5 is not upregulated by tadalafil in cultures of human penile cells. J Sex Med 2006;3:84-95.