The prostate is a walnut-sized gland that forms part of the male reproductive system. The gland is made of two lobes, or regions, enclosed by an outer layer of tissue. The prostate also surrounds the urethra, the canal through which urine passes out of the body.
As the prostate enlarges, the layer of tissue surrounding it stops it from expanding, causing the gland to press against the urethra like a clamp on a garden hose. The bladder wall becomes thicker and irritable. The bladder begins to contract even when it contains small amounts of urine, causing more frequent urination. Eventually, the bladder weakens and loses the ability to empty itself. Urine remains in the bladder. The narrowing of the urethra and partial emptying of the bladder cause many of the problems associated with benign prostatic hyperplasia.
Avodart prevents the change of testosterone to dihydrotestosterone in the body. Dihydrotestosterone is involved in the progress of benign prostatic hyperplasia. Benign prostatic hyperplasia is enlargement of the prostate and occurs only in males.