Phosphodiesterase 5 inhibitors: preclinical and early phase breakthroughs for impotence treatments.

It is our opinion that more robust clinical trials are required before these medications can be made available in the United States. Additionally, the field of urology may benefit from pursuing other avenues of pharmacotherapy, such as injections, tablets with a different mechanism of action, or stem cell therapy, to restore the integrity of the endothelium within the penis.