To evaluate the efficacy and safety of solifenacin succinate as add-on therapy for overactive bladder (OAB) symptoms in men who have been treated for benign prostatic hyperplasia (BPH) with tamsulosin hydrochloride for at least 6 weeks

Study drugs are administered for 14 weeks in total, including a 2-week run-in period (single blind) and a 12-week treatment period (double blind). After written informed consent, study drugs for the run-in period are orally administered once daily after breakfast for two weeks to subjects who fulfill the inclusion and exclusion criteria. Then, subjects are randomized and orally treated with study drugs for the treatment period once daily after breakfast for 12 weeks

Inclusion Criteria:

• Patients with benign prostatic hypertrophy who have been treated with tamsulosin for at least 6 weeks
• Patients with urgency episodes and frequent micturitions
• Written informed consent has been obtained
• Uroflowmetry-Q max ≥ 5 mL/sec, and Post Void Residual Volume < 50 mL

Exclusion Criteria:

• Patients with suspected symptoms of OAB whose onset is only transient (drug-induced, psychogenic, etc.)
• Patients with obvious stress urinary incontinence
• Patients with complications or who have a past history of a bladder tumor
• Patients with urethral stricture or bladder neck stenosis
• Patients with a history of surgery causing damage to the pelvic plexus
• Patients with history of hypersensitivity to α receptor blockers, a/b receptor blockers, or anticholinergic drugs
• Patients with orthostatic hypotension, ulcerative colitis, hyperthyroidism, dementia or cognitive dysfunction, Parkinson's disease, or cerebrovascular disorder