Enzyme Inhibitors
Enzyme inhibitors (also called 5-alpha reductase inhibitors) block or inhibit the enzyme called 5-alpha reductase. This enzyme is responsible for converting testosterone to dihydrotestosterone (DHT) -- the form of testosterone that stimulates growth of prostate glandular tissue. The result of taking an enzyme inhibitor is a lowering of DHT levels in the prostate, and eventually, a shrinking of the prostate. This may improve symptoms and urinary function in men whose primary problem is an obstructed urethra caused by an enlarged gland. This treatment seems to work best in men with larger prostates. Drugs in this class include finasteride (Proscar, Propecia) and dutasteride (Avodart).









