Dutasteride: a review of current data on a novel dual inhibitor of 5alpha reductase.

Dutasteride is used in the treatment of benign prostatic hyperplasia. Like finasteride, it reduces serum prostate-specific antigen levels by approximately 50% at 6 months and total prostate volume by 25% in 2 years. It differs from finasteride in that it inhibits both isoenzymes of 5alpha reductase and results in near-complete suppression of serum dihydrotestosterone. Randomized placebo-controlled trials over 2 years have shown the efficacy of dutasteride in symptomatic relief, improvements in quality of life and peak urinary flow rate, and reduction of acute urinary retention events and need for surgery. Side effects occurring in therapy with dutasteride are decreased libido, erectile dysfunction, ejaculation disorders, and gynecomastia. However, when dutasteride treatment is compared with placebo, these sexual adverse events are only modestly elevated. Long-term use over 4 years did not increase side effects. An efficient treatment of side effects is the combination of dutasteride and tamsulosin, especially for patients with large prostate volumes. Finally, the anticancer properties of dutasteride have been shown in placebo-controlled trials and are being investigated in the ongoing Reduction by Dutasteride of Prostate Cancer Events (REDUCE) trial.