An Effectiveness and Safety Study Comparing Oxybutynin Chloride Plus FLOMAX (Tamsulosin HCl) and Placebo Plus FLOMAX (Tamsulosin HCl) for the Treatment of Lower Urinary Tract Symptoms.

The objective of this double-blind (neither the patient nor the physician knows whether drug or placebo is being taken, or at what dosage), randomized (patients are assigned different treatments based on chance), parallel group trial is to evaluate the safety and effectiveness of oxybutynin extended release tablets 10 mg per day for 12 weeks in conjunction with an alpha-blocker for the treatment of lower urinary tract symptoms (LUTS). The hypothesis of the study is that oxybutynin extended release tablets 10 mg plus tamsulosin 0.4 mg will be more effective than tamsulosin 0.4 mg plus placebo in the treatment of lower urinary tract symptoms as measured by change of the total International Prostate Symptom Score (I-PSS) from baseline to Week 12 or the Final Visit. Safety assessments include Peak Flow Rate (PFR) and Post-Void Residual (PVR) volume, adverse events, vital signs and physical exams. Patients will receive oxybutynin extended release 10 mg plus tamsulosin 0.4 mg or placebo plus tamsulosin 0.4 mg every day for 12 weeks.

Inclusion criteria

• Diagnosis of lower urinary tract symptoms with urgency and frequency with or without urge incontinence
• have had at least 4 weeks of 0.4 mg/day tamsulosin therapy
• an International Prostate Symptom Score (I-PSS) >=13
• irritative component I-PSS score >= 8
• max flow >= 8ml/sec with voided volume >= 125 ml, post-void residual volume <= 150 ml on two occasions.

Exclusion criteria

• Clinically significant medical problems or other organ abnormality or pathology
• Prostate-Specific Antigen (PSA) >= 4 ng/ml
• history of inability to empty bladder completely or not at all
• uncontrolled narrow angle glaucoma
• history of any prostate surgery or treatment
• history of significant gastrointestinal problems.