5α-Reductase Inhibitors

In the 1997 document, finasteride, a 5α-reductase inhibitor, was shown to be effective in treating benign prostatic hyperplasia (BPH) by reducing prostate size and improving urinary flow rates, with a decrease in serum DHT by about 70% and prostatic DHT by about 90%. It also demonstrated potential in treating male pattern baldness, with a 1-year study showing a 107-hair improvement over placebo and 48% of men experiencing improvement. For hirsutism, finasteride at 5 mg daily showed significant improvement without adverse side effects in women. However, it was not effective for acne due to the predominance of type 1 5α-reductase in sebaceous glands. While finasteride did not affect the size of metastatic prostate cancer lesions, it delayed the increase in PSA levels post-surgery. An ongoing trial with 18,000 men was investigating its potential to prevent prostate cancer. The safety profile of finasteride was considered favorable, with a low incidence of side effects. Further long-term studies were needed to confirm these findings.