1. Primary Objective:

   To evaluate the dose-response relationship of tarafenacin on efficacy.

2. Secondary Objectives:

   • To compare 12 weeks' efficacy of different doses of tarafenacin to that of placebo in patients suffering from Overactive Bladder. .
   • To compare the tolerability of different doses of tarafenacin to that of placebo in patients suffering from Overactive Bladder. .

< Inclusion Criteria>

1. Patient of either sex aged 20 to 80 years (both inclusive);

2. Patients suffering from Overactive Bladder. based on cardinal symptoms (urgency, nocturia, frequency with or without urge incontinence) for at least 6 months prior to inclusion;

3. Patients who document the following symptoms in a 3-day diary card during the 14 day placebo run-in period

   • An average of ≥8 micturitions/24 hours;
   • Greater than or equal to three incontinence episodes
   • A total of ≥3 urgency episodes.

<Exclusion Criteria>

1. Patients with Clinically significant bladder outlet obstruction
2. Patients with predominant stress incontinence (>2 episode/week)
3. Patients with significant urogenital disease such as recurrent urinary tract infection (more than 2/6 months), bladder calculi, interstitial cystitis, urothelial tumours, hysterectomy or prostatectomy in the previous six months;
4. Females diagnosed with bladder cancer
5. Males diagnosed with bladder cancer
6. Patients with obstructive disease of the gastrointestinal tract, intestinal inflammatory disease, severe ulcerative colitis, inflammatory bowel disease, toxic megacolon, intestinal atony or paralytic ileum
7. Patients with acute Noehyeolgwangye disease, significant Cardiovascular Disease (arrhythmias, unstable angina pectoris, myocardial infarct, or are using a pacemaker), significant Orthostatic hypotension in the previous six months
8. Patients diagnosed with closed angle glaucoma or shallowness of the anterior chamber
9. Patients with any contraindication to antimuscarinic drugs