Finasteride and Dutasteride
Finasteride and dutasteride are drugs used to lower the amount of male sex hormones made by the body. These drugs block the enzyme that changes testosterone into dihydrotestosterone (DHT). Higher than normal levels of DHT may play a part in developing prostate cancer. Taking finasteride or dutasteride has been shown to lower the risk for prostate cancer, but it is not known if these drugs lower the risk of death from prostate cancer.
The Prostate Cancer Prevention Trial (PCPT) studied
whether the drug finasteride can prevent prostate cancer in healthy men 55
years of age and older. This prevention study showed there were fewer prostate cancers in the group of men that took finasteride compared with the group of men that did not. Also, the men who took finasteride who did have prostate cancer had more aggressive tumors. The number of deaths from prostate cancer was the same in both groups. Men who took finasteride reported more side effects compared with the group of men that did not, including erectile dysfunction, loss of desire for sex, and enlarged breasts.
The Reduction by Dutasteride of Prostate Cancer Events Trial (REDUCE) studied whether the drug dutasteride can prevent prostate cancer in men aged 50 to 75 years at higher risk for the disease. This prevention study showed there were fewer prostate cancers in the group of men who took dutasteride compared with the group of men that did not. The number of less aggressive prostate cancers was lower, but the number of more aggressive prostate cancers was not. Men who took dutasteride reported more side effects than men who did not, including erectile dysfunction, loss of desire for sex, less semen, and gynecomastia (enlarged breasts).