Dutasteride: A Review of Current Data on a Novel Dual Inhibitor of 5-Alpha Reductase

Dutasteride was reviewed as a dual inhibitor of 5alpha reductase, used for treating benign prostatic hyperplasia. It reduced serum prostate-specific antigen levels by about 50% in 6 months and prostate volume by 25% over 2 years. Unlike finasteride, it inhibited both isoenzymes of 5alpha reductase, leading to near-complete suppression of serum dihydrotestosterone. Trials showed its efficacy in improving symptoms, quality of life, urinary flow, and reducing urinary retention and surgery needs. Side effects included decreased libido, erectile dysfunction, ejaculation disorders, and gynecomastia, but these were only modestly higher than placebo. Long-term use over 4 years did not increase side effects, and combining dutasteride with tamsulosin was effective for large prostate volumes. Its anticancer properties were under investigation in the REDUCE trial.