finasteride

n a drug that causes shrinkage of the prostate gland. It is administered by mouth both to relieve the symptoms of urinary retention caused by an enlarged gland obstructing the outflow of urine from the bladder and to reduce the risk of urinary retention. The drug acts by reducing androgenic stimulation of the prostate, inhibiting the enzyme responsible for converting testosterone to its more active metabolite, 5-dehydroxytestosterone (5-DHT), within the gland. It is sometimes also prescribed in men who have recurrent bleeding from the prostate.