Can Overactive Bladder Medication Harm Your Cognitive Health?

Overactive bladder (OAB) is a common disorder affecting about 33 million Americans and 30% of people over 65. Research suggests that one of the most popular OAB medications, oxybutynin, may harm brain health and increase dementia risk.

OAB is a combination of urinary tract symptoms including frequent urination and the inability to control urination. Oxybutynin is a common treatment for OAB that works by relaxing bladder muscles. Its benefits combined with the high prevalence of OAB in the elderly make it a very popular drug—over a quarter of all elderly people with OAB have been prescribed oxybutynin. It remains popular despite several studies linking oxybutynin use to cognitive side effects and increased dementia risk. This is troubling because elderly patients are already more at risk for dementia, and oxybutynin may worsen the situation.

WHAT THE EVIDENCE SAYS
One clinical trial of 12 subjects with an average age of 69 reported that oxybutynin treatment for 6 weeks resulted in significant decreases in 7 out of 15 cognitive measures [1]. A recent observational study was even more alarming. It found that oxybutynin treatment was associated with a 2.3-fold increased risk of dementia in people with diabetes compared to those who did not take this class of medication [2]. However, the evidence is mixed; another study found that oxybutynin treatment did not result in cognitive impairment compared to placebo in nursing home residents with cognitive impairment [3].

It doesn't appear that all OAB medications carry the risk of cognitive side effects. Several studies have compared the chemical properties of OAB medications and how they may affect dementia risk. When compared to other OAB medications such as tolterodine, trospium, solifenacin, and darifenacin, oxybutynin had the highest percentage of patients reporting side effects such as headache, sleepiness, and dizziness. There was little to no incidence of such side effects with patients on darifenacin, trospium, or fesoterodine. These drugs are newer than oxybutynin and designed to mitigate many of its issues. Drugs such as trospium, tolterodine, and darifenacin have chemical properties that make them unlikely to reach the brain, and therefore less likely to cause cognitive side effects [4][5]. However, these drugs are newer and less commonly prescribed so we may not know the full extent of their cognitive side effects yet. Another study suggested that Oxytrol, a transdermal patch formulation of oxybutynin, causes fewer side effects compared to the oral formulation because of differences in how the drug is metabolized [6].

WHAT YOU CAN DO
Although the evidence isn't conclusive, there is still reason to be cautious before and while using oxybutynin, particularly if you have other risk factors for dementia. If you have OAB and are concerned about the side effects of your medication, talk to your doctor about your options. Research suggests there are several alternatives to oxybutynin that have similar efficacy without the potential risk to cognitive health.

1. Katz IR, Sands LP, Bilker W et al. (1998) Identification of medications that cause cognitive impairment in older people: the case of oxybutynin chloride. J Am Geriatr Soc 46, 8-13.
2. Yang YW, Liu HH, Lin TH et al. (2017) Association between different anticholinergic drugs and subsequent dementia risk in patients with diabetes mellitus. PLoS One 12, e0175335.
3. Lackner TE, Wyman JF, McCarthy TC et al. (2008) Randomized, placebo-controlled trial of the cognitive effect, safety, and tolerability of oral extended-release oxybutynin in cognitively impaired nursing home residents with urge urinary incontinence. J Am Geriatr Soc 56, 862-870.
4. Chancellor M, Boone T (2012) Anticholinergics for overactive bladder therapy: central nervous system effects. CNS Neurosci Ther 18, 167-174.
5. Munjuluri N, Wong W, Yoong W (2007) Anticholinergic drugs for overactive bladder: a review of the literature and practical guide. The Obstetrician & Gynaecologist 9, 9-14.
6. Cohn JA, Brown ET, Reynolds WS et al. (2016) An update on the use of transdermal oxybutynin in the management of overactive bladder disorder. Ther Adv Urol 8, 83-90.

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