The primary objective is to compare the efficacy of silodosin 4 and 8 mg once daily with placebo in the treatment of subjects with moderate to severe abacterial chronic prostatitis/chronic pelvic pain syndrome during a 12 week treatment period. The secondary objective is to compare the safety of silodosin 4 and 8 mg once daily with placebo.

A Multi-Center, Double-Blind, Placebo-Controlled Investigation of Silodosin in the Treatment of Subjects With Moderate to Severe Abacterial Chronic Prostatitis/Chronic Pelvic Pain Syndrome.

Inclusion Criteria:

• Male, at least 18 years of age
• Has a total NIH-CPSI total score of 15
• Has a NIH-CPSI pain score of 8
• Has had pain in the pelvic region for at least 3 months prior to screening

Exclusion Criteria:

• Has previously participated in a Watson study with silodosin
• Has previously received α-blocked therapy for chronic prostatitis/chronic pelvic pain syndrome or is currently receiving α-blocked therapy for any condition
• Has experience ≥2 urinary tract infections within the previous 12 months
• Has any medical condition that in the opinion of the investigator precludes safe participation in the study
• Has any medical condition that could confound the efficacy evaluation
• Is receiving ketoconazole, or other known potent inhibitors of cytochrome P450 3A4 or any medication in the opinion of the investigator that precludes safe participation in the study
• Is receiving any medication that in the opinion of the investigator that could confound the efficacy evaluation
• Has participated in a study involving the administration of an investigational agent within the past 30 days