Debruyne F et al. (2004) Efficacy and safety of long-term treatment with the dual 5α-reductase inhibitor dutasteride in men with symptomatic benign prostatic hyperplasia. Eur Urol 46: 488–495

Dutasteride has been investigated as a treatment for men with benign prostatic hyperplasia (BPH). The drug suppresses serum dihydrotestosterone (DHT) by selectively inhibiting both type 1 and type 2 5α-reductase isoenzymes. Prostate volume is reduced as a consequence, and other symptoms of BPH are improved. Debruyne et al. have recently reported long-term safety and efficacy results for dutasteride in this setting.

The new data were pooled from a 2-year open-label extension period that followed three randomized, phase III trials comparing dutasteride with placebo. A total of 2,340 men were included in the extension phase, all of whom received dutasteride 0.5 mg daily. In the preceding double-blind periods, patients had received dutasteride (n = 1,188; group D/D) or placebo (n = 1,152; group P/D) for 2 years.

A reduction in total prostate volume was seen in both study groups during the open-label phase, along with improvements in disease symptoms and urinary flow. Patients in the D/D group showed the greater improvement. The incidence of acute urinary retention and BPH-related surgery was low in both groups. Sexual adverse events tended to become less frequent with continued treatment, although a low incidence of gynecomastia persisted throughout the study.

In conclusion, the improvements in BPH disease measures seen in the phase III trials appeared to continue during long-term therapy, and Debruyne et al. note that the drug was well tolerated.