Oxybutynin Case Study – No Efficacy!

MS is a 78-year-old female with a history of overactive bladder with urinary frequency and urge incontinence. Her current medications include: Oxybutynin 5 mg twice daily, Hydrochlorothiazide 25 mg daily, Lisinopril 10 mg daily, Sertraline 25 mg daily, Lorazepam 0.25 mg daily PRN anxiety (no use in the last month), Acetaminophen 500 mg TID, and Calcium and Vitamin D supplements.

Mary presents to the clinic with complaints of increased confusion, two recent falls within the last month, and no significant improvement in urinary frequency despite being on oxybutynin for the past three months.

Mary was started on oxybutynin 5 mg twice daily three months ago for urinary frequency and urge incontinence due to overactive bladder. She has been experiencing urinary frequency (up to 10 times per day) for the past year, which has been impacting her quality of life. Despite medication, she reports no significant reduction in the frequency of urination. Additionally, over the past month, Mary’s daughter has noticed increased confusion, forgetfulness, and lethargy. She has also fallen twice in the past two weeks, though there was no serious injury.

Her daughter is particularly concerned about the changes in Mary’s mental status, as she was previously mentally sharp and independent. Mary is having trouble remembering daily tasks, and her balance seems to have worsened, especially when getting up from a chair or moving around the house.

Without any use of the lorazepam, this is a pretty easy case to assess. Oxybutynin is an anticholinergic medication commonly used to treat overactive bladder. However, in older adults, anticholinergic agents can have significant adverse effects, including confusion, delirium, dry mouth, constipation, and an increased risk of falls (excellent board exam question). Older adults are particularly susceptible to these side effects due to changes in pharmacokinetics and pharmacodynamics with aging, as well as increased sensitivity to medications that affect the central nervous system. The oxybutynin can cause all of these potential side effects and the part that bugs me the most is we are getting no benefit from this medication. I would’ve liked to have seen this medication reassessed sooner (i.e. after 2-4 weeks) for efficacy. If we had done this sooner, we could have reduced the risk of these adverse effects occurring.

Oxybutynin should be discontinued and hopefully fall risk will be reduced and cognition and lethargy will improve. For the ongoing urinary frequency, it would be reasonable to consider reassessing other options to replace hydrochlorothiazide. If medication therapy is still desired and altering hydrochlorothiazide is not effective, an alternative medication to treat OAB would be a beta-3 agonist such as mirabegron or vibegron.

My biggest take-home point with all medications used for OAB, urge incontinence, or urinary frequency symptoms is to reassess whether the medication is helping the patient. If it isn’t, these medications need to be discontinued as they are associated with a significant number of adverse effects!

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