The primary purpose of this clinical trial is to compare in a double-blind randomized trial, the efficacy and safety of ciprofloxacin MR 1000 mg tablets given as a single-dose or as a multiple-dose regimen for the prevention of infectious complications in patients undergoing transrectal needle biopsies of the prostate (TRNBP).

Inclusion Criteria:

• Transrectal needle biopsy of the prostate required.
• A clean-catch midstream-urine (MSU) culture negative (<104 CFU/mL) for possible pathogens at the Pre-Therapy Visit prior to the TRNBP.
• Gastrointestinal absorption is adequate as evidenced by passage of gas or feces per rectum and patient can tolerate oral food, fluids, and medication without vomiting or diarrhea.

Exclusion Criteria:

• History of hypersensitivity to ciprofloxacin or other quinolone antibiotics
• Valvular heart disease that requires antibiotic prophylaxis to prevent bacterial endocarditis
• Concomitant use of theophylline, probenecid, or warfarin at any time during the entire study
• Renal insufficiency
• Known or suspected central nervous system disorder that may predispose to seizures or lower the seizure threshold
• Absolute neutrophil count (ANC) <1000/mm3
• Human immunodeficiency virus (HIV) infection with a CD4 count <200 cells/micL. HIV testing is NOT required
• Antibiotic administration within one week of the TRNBP
• Severe hepatic insufficiency (Child-Pugh C)