Clinical Course of the Benign Prostate Hyplasia Patients during the Intermittent Use of 5-Alpha Reductase Inhibitors

Purpose 5-Alpha reductase inhibitors (5ARI), inhibit the conversion of testosterone to dihydrotestosterone, which is essential in prostate hyperplasia, and decreases the prostate volume directly. On the other hand, 5ARI have a range of side effects, such as sexual dysfunction. After the discontinuation of 5ARI, prostate regrowth occurs rapidly until it reaches the baseline size. This study examined the effects of 5ARI when used intermittently. Materials and Methods Between March 2009 and May 2017, patients who visited one physician's outpatient clinic and were diagnosed with BPH underwent transrectal ultrasonography. The selected patients began to take 5ARI until the prostate size decreased at least 10% of the baseline (the first medication). After confirming adequate prostate shrinkage, the patients stopped medication until prostate regrowth reached 50% of the decreased size. After regrowth, they restarted medication for one year (second medication). The prostate size, serum prostate specific antigen (PSA) levels, international prostate symptom score (IPSS) scores, and maximum flow rate (Qmax) in uroflowmetry were collected after the first and second medication and compared using paired t-tests. Results Sixty patients with a mean age of 65.1 years were included in the study. The prostate size and serum PSA level increased after the second medication compared to the first, and the prostate reduction and Qmax in uroflowmetry decreased significantly. On the other hand, the symptoms felt by the patients surveyed by the IPSS scores showed no significant difference. Conclusions 5ARI appear to be less effective in reducing the prostate volume and improving uroflowmetry after discontinuation.