Hi Dale Conrad,   You can read about Avodart here in the drugs database. Here is more information on Flomax.  Avodart shrinks the prostate by reducing the hormones that is responsible for the prostate growth. Flomax shrinks the prostate by relaxing the muscles in the bladder neck and prostate. Avodart lists several side effects, one of which is impotency, Flomax does not list impotency as a main side effect. Your doctor has prescribed the medication he thinks will treat your particular condition the best.    While online sites are great places to get information, they can not take the place of your doctor's care and advice. Stay in touch and let us know how you are doing! Vicki M