Pilot Deprescribing of Antimuscarinic Overactive Bladder Medications in Parkinson Disease

Evaluating the Effect of Deprescribing Antimuscarinic Overactive Bladder Medications on Cognitive Function and Quality of Life of Individuals With Parkinson Disease: A Pharmacist-led Series of N-of-1 Trials

This is an unblinded, non-randomized National Institute of Health (NIH) Stage I of Behavioral Intervention Development trial. The investigators will enroll 20 subjects with Parkinson disease (PD) for a series of 20 of N-of-1 trials. The investigators will use a single-arm crossover titration/reversal design ("ON" [A] vs. "OFF" [B]) with up to 4 periods. All participants will follow the sequence ABAB. Each period will last up to 10 weeks, allowing for sufficient time for up-titration and onset of drug action, and down-titration and washout. Each participant will have the option to participate in less (2-3) or more (3-4) periods depending on whether additional information is needed to make an informed decision about continuing or discontinuing the overactive bladder (OAB) antimuscarinic at the end of the study. The intervention drug will be an OAB antimuscarinic, previously prescribed to the participants by their physician. The investigators will reduce the dose of each OAB antimuscarinic by 25-50% every 1-2 weeks during the "OFF" [B] period, with the goal to completely discontinue the medication.

Inclusion Criteria:

1. 60+ years old at time of enrollment
2. Have a diagnosis of Parkinson disease (PD) made by a movement disorders specialist
3. Life expectancy of at least six months
4. Are on an antimuscarinic for overactive bladder (OAB) symptoms (without concurrent use of a beta-3 agonist) for at least 3 months
5. Are able to provide informed consent
6. Are able to complete online surveys/questionnaires
7. Are able to receive telephone calls and Zoom calls/telehealth meeting

Exclusion Criteria:

1. Have untreated or uncontrolled hypertension (blood pressure [BP] ≥180/110 mmHg),
2. Have active urinary tract infection (UTI) or chronic/recurrent UTI (≥2 UTIs in six months or ≥3 in one year)
3. Have moderate or severe hepatic impairment (Child-Pugh Score Class B or C)
4. Have severe renal impairment (Estimated Glomerular Filtration Rate [eGFR] <30 mL/min/1.72 m2) or end-stage renal disease (on dialysis or renal replacement therapy)
5. Have prior history of hypersensitivity or intolerance to mirabegron or vibegron
6. Have existing cognitive impairment (Montreal Cognitive Assessment [MoCA] score <22/30) or psychiatric disorder that preclude informed consent
7. Have any other condition that, in Principal Investigator (PI) and Co-PI's opinion, makes the individual unsuitable for study participation
8. On non-oral form of OAB antimuscarinics, the oral solution formulation of oxybutynin chloride or the oral suspension formulation of solifenacin succinate (due to complicated tapering process)