What's known on the subject? and What does the study add? Phosphodiesterase type-5 (PDE5) inhibitors (tadalafil, vardenafil, and sildenafil) are well-known treatment options for men with erectile dysfunction and should be taken before anticipated sexual activity. Tadalafil is also approved for once daily use in men with erectile dysfunction. Recent 12-week studies in men with benign prostatic hyperplasia (BPH) have shown once daily use of tadalafil significantly reduced their urinary symptoms. This article is the first to report the long-term safety and maintenance of efficacy for once-daily use of tadalafil in men with urinary symptoms secondary to BPH. OBJECTIVE center dot To evaluate the 1-year safety of 5 mg of tadalafil once daily in men with lower urinary tract symptoms secondary to benign prostatic hyperplasia (BPH-LUTS); efficacy measures were included to evaluate the maintenance of efficacy after an additional year of treatment. PATIENTS AND METHODS center dot In total, 427 men who completed a 12-week, placebo-controlled, dose- finding study assessing once-daily tadalafil (2.5, 5, 10 or 20 mg) or placebo elected to continue into the open-label extension period. Safety and efficacy parameters were assessed after 1 month and every 3 months. RESULTS center dot In total, 299 patients (69.9%) completed the 1-year, open-label extension period. Treatment-emergent adverse events (TEAEs) were reported by 57.6% of patients, with most TEAEs being mild (44%) or moderate (45%) in severity; the most common TEAEs (>= 2%) were dyspepsia, gastro-oesophageal reflux disease, back pain, headache, sinusitis, hypertension and cough. Twenty-two patients (5.2%) discontinued as a result of AEs. During the open-label extension period, mean prostate-specific antigen increased from 1.6 +/- 1.3 ng/mL to 1.8 +/- 1.4 ng/mL. center dot Mean post-void residual volume was 61.1 +/- 60.4 mL at study entry and 42.2 +/- 64.1 mL after the open-label extension period. Changes in the total International Prostate Symptom Score (IPSS), IPSS irritative and obstructive subscores, IPSS health-related quality of life and BPH Impact Index were maintained after 1 year. In sexually-active patients with erectile dysfunction, improvements in the International Index of Erectile Function-Erectile Function domain were maintained after 1 year. CONCLUSION center dot In men with BPH-LUTS, 5 mg of tadalafil once daily during 1 year of treatment was well tolerated and efficacy changes were maintained.