Anticholinergic Therapy for Overactive Bladder in Parkinson's Disease

Inclusion Criteria: * Diagnosis of idiopathic PD (ICD9=332.0) * MMSE 24, able to give informed consent and complete questionnaires and voiding diaries. * Urological work-up within 3 months of enrollment to: * Rule out treatable causes of urinary symptoms * Urinalysis (UA) * Post-void residual ultrasound (PVR) * Urinary cytology * Documented symptoms OAB on screening 3-day voiding diary: * Average of 1 urgency episode / 24 hours, and * Average of 8 micturitions / 24 hours * Subjective complaints of symptoms for 3 months Exclusion Criteria: * Exposure to anticholinergics or antispasmodics within the last 4 weeks (among them: atropine, tolterodine, benztropine, trihexyphenidyl, dicyclomine, hyoscyamine, and scopolamine) * Exposure to drugs with known effects on cognition (i.e. opioids, benzodiazepines or sedating antihistamines) within the last week * Exposure to drugs contraindicated or cautioned in use with the 2 study medications (drugs that also use the cytochrome P450 enzyme, primarily CYP3A4). These include: ketoconazole, itraconazole, miconazole, erythromycin, clarithromycin, ritonavir, nelfinavir, nefazodone, flecainide, thioridazine and tricyclic antidepressants. * Nonpharmacological treatment of OAB within the last 4 weeks (for example: biofeedback, physical therapy, acupuncture) * Uncontrolled narrow angle glaucoma * History of gastric or urinary retention / dysmotility (ulcerative colitis, myasthenia gravis and severe constipation) * History of hepatic or renal impairment * History of severe gastro-esophageal reflux disease and/or use of bisphosphonates, patients at risk for esophagitis * Previous exposure to anticholinergic for OAB symptoms that resulted in side effects that caused cessation of the medication