Korea has newly adopted 8mg Silodosin once daily. Against these backdrops, this clinical study is designed to demonstrate that the newly adopted dose is not inferior to the existing dose in its efficacy and safety.

Silodosin is a highly selective α1A-adrenoceptor antagonist for the treatment of the signs and symptoms of BPH. 4mg Silodosin twice daily has been approved in Asia including Japan and Korea. In US, 8mg Silodosin once daily with the FDA approval is already available. Korea has newly adopted 8mg Silodosin once daily. Against these backdrops, this clinical study is designed to demonstrate that the newly adopted dose is not inferior to the existing dose in its efficacy and safety. The study used double-blind, random assignment in Korean men with signs and symptoms of BPH for 12 weeks.

Inclusion Criteria:

Patients who have been diagnosed with BPH through digital rectal exam or ultrasonographic findings and meet the following criteria.

• Outpatients aged 50 or over
• Patients with a total I-PSS score of 8 or higher and a QoL score of 3 or higher
• Patients with a prostate volume measured by transabdominal ultrasonography, or TRUS of 20 ml or greater
• Patients with a maximum urinary flow rate (Qmax_) of 15ml/sec or below (whose a void urinary volume of 120ml or greater)

Exclusion Criteria:

• Patients with a residual urinary volume of 200ml or greater
• Patients with a history of prostatectomy
• Patients with a history of intrapelvic radiation therapy
• Patients with a history of prostatic hyperthermia
• Patients with prostate cancer or suspected prostate cancer
• Patients with complications considered likely to affect urinary passing such as neurogenic bladder, bladder calculus and active urinary tract infection. UTI
• Patients conducting self-catheterization
• Patients with renal impairment (serum creatinine of 3.0 mg/dl or greater)
• Patients with severe heptic disorders (hepatic insufficiency, cirrhosis, jaundice, hepatoma) or with a total bilirubin of 3.0mg/dL or greater or AST/ALT 2.5 times higher than normal level
• Patients with history of severe arrhythmia, cardiac failure, cardiac infarction, unstable angina, cerebral infarction within 6 months
• Patients with a history of an allergy to α-blockers
• Patients with orthostatic hypotension at around screening visit
• Patients with an experience of other investigational product treatments within 4 weeks form screening visit.
• Patients with a PSA of 10 or over, Patients with tumor identified by a prostate biopsy with a PSA of 4 or over (For patients taking 5α-reductase inhibitors for more than 3 months are presumed to have double than their actual PSA levels.)
• Patients who have taken unstable doses of antidepressants within the 3 months or who are expected to take unstable doses during the study
• Patients who have taken alpha blockers within the 2 weeks from the start of the therapy
• Patients who have taken unstable doses of 5α-reductase inhibitors within the 3 months from the start of the therapy or who are expected to take unstable doses during the study.
• Patients disqualified by the investigator.