A recently published paper addressed the interesting topic of prevention of erectile dysfunction (ED) with tadalafil, a phosphodiesterase-type 5 inhibitor (PDE5i) in patients undergoing radiation therapy for localized prostate cancer. Tadalafil 5 mg or placebo was administered once-daily for 24 weeks in patients undergoing external-beam radiotherapy (EBRT) or brachytherapy (BT) for prostate cancer. This randomized trial did not show superior efficacy of the active drug compared with placebo 4-6 weeks after stopping the study drug. Furthermore, patients younger than 65 years did not respond significantly better than older patients.