Finasteride is an antiandrogen which acts by inhibiting 5-alpha reductase, the enzyme that converts testosterone to dihydrotestosterone. It is used in benign prostatic hyperplasia (BPH) in low doses, and in prostate cancer in higher doses. Additionally, it is registered in many countries for male-pattern baldness. Drug trade names include Propecia? and Proscar ? both products of Merck & Co. (the former is marketed for hair loss in male pattern baldness, and the latter for BPH).

The Prostate Cancer Prevention Trial (PCPT) showed at a dosage of 5mg per day, as is commonly prescribed for BPH, though much higher than the 1mg generally prescribed for hair loss, participants taking finasteride were 25% less likely to have developed prostate cancer at the end of the trial compared to those taking a placebo.[1] However, the cancers that developed in the men taking finasteride looked like they were more likely to grow and spread. The reason for this is not known. The study researchers are continuing to watch these men to see if these cancers truly are more aggressive. At lower doses, this effect is less well-defined. Finasteride is not indicated for use by women.

Finasteride lowers levels of a key hormone called DHT (dihydrotestosterone), which is a major cause of prostate growth. Lowering DHT leads to shrinkage of the enlarged prostate gland in most men. This can lead to gradual improvement in urine flow and symptoms over the next several months. Finasteride will help reduce the risk of developing a sudden inability to pass urine and the need for surgery. However, since each case of BPH is different, you should know that:

• Even though the prostate shrinks, you may NOT notice an improvement in urine flow or symptoms.
• You may need to take Finasteride for six (6) months or more to see whether it improves your symptoms.
• Therapy with Finasteride may reduce your risk for a sudden inability to pass urine and the need for surgery.

Before taking any prescription medicine, it is important that you consult your doctor!