Finasteride in the treatment of benign prostatic hypertrophy: an update. New indications for finasteride therapy.

A phenomenon of the prostate gland, which is also shared by hair follicles, is that it is little influenced by testosterone (T) for androgenic stimulation, but instead by its metabolite 5alpha-dihydrotestosterone (DHT). By blocking the conversion of T to DHT, the circulating level of DHT is reduced by 80%, the size of the prostate gland is reduced by about 20% and the level of prostate-specific antigen (PSA) by about 50%. Treatment of patients with obstructive benign prostatic hypertrophy (BPH) with the drug Finasteride leads to a moderately improved urinary flow, symptomatic improvement and halts the natural progress of the disease. Since DHT potentiates the effect of testosterone on erectile function, the side-effects are impotence in 3% of patients, decreased ejaculatory volume, and gynaecomastia in 0.4% of patients. The drug could be regarded as a safe way to treat moderately symptomatic BPH. The efficacy of the drug is long-lasting (more than 7 years). It has also been tried in prostate cancer, but is less effective. It reduces PSA levels by 50% and, in combination therapy, therefore, PSA levels remain low for longer when Finasteride is added. An important finding is the efficacy of Finasteride treatment in haematuria from BPH. The drug interacts with vascular endothelium growth factor and efficiently prevents new bleeding. It could be regarded as a first-line therapy for this type of haematuria. Finasteride can also be used to stop male baldness. It seems particularly effective in men aged 20-40 years; 85% of patients stopped losing hair when given Finasteride. When the treatment was stopped hair loss continued, thus therapy may have to be "lifelong".