Propecia (finasteride) is a medicine popularly prescribed for male pattern baldness. It can be also used for patients diagnosed with benign prostatic hyperplasia. If you are taking this medicine for the treatment of hair loss, make sure you do not miss any doses, as you may not achieve the results desired. Propecia will be efficient for as long as you carry on with your treatment, so you may need to be taking it for the rest of your life. Propecia is not known to interact with any other medications, but that dose not mean you are not supposed to inform your doctor of any drugs you intend to be taking along with it. Tell your health care provider before starting the treatment if you have or used to have abnormal liver enzyme tests, stricture of the urethra, inability to urinate, liver disease, bladder muscle disorder, or prostate cancer, as your dose may need to be revised to make sure you will get maximum benefits from your treatment. Such mild side effects as headache, decreased sexual desire, decreased amount of semen, swelling or tenderness in your breasts, pain in the testicles, runny nose, or impotence are not expected to get worse with time and therefore do not need to be reported to your health care provider.