Has recent research indicated that Proscar is not as effective in reducing prostate gland size as originally thought?
Jonathan P. Jarow, M.D. responds: The normal growth and development of the prostate is dependent upon male hormones. The principal male hormone present in the blood stream is testosterone, which is produced in the testes. This hormone is converted into a more potent male hormone called dihydrotestosterone within the prostate gland. Proscar blocks the conversion of testosterone into dihydrotestosterone, thus lowering both blood and prostate concentrations of this potent hormone. In controlled studies Proscar has a significant effect upon the size of the prostate gland, with a consistent reduction of approximately 20 percent in all studies. However, the average improvement in urinary flow rates and reduction of symptoms in symptomatic patients receiving this drug is much less dramatic. This suggests that the reduction of urinary stream and symptoms in men with enlarged prostates may not be specifically related to prostate size but potentially, to prostate tone. This would explain why oth
