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 . 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 . 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 .
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 . 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 .
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.
Ebony Evans was a summer intern at Aging and Alzheimer's Prevention at the Alzheimer's Drug Discovery Foundation. She is a Doctor of Pharmacy candidate at the Ohio State University College of Pharmacy. Ms. Evans was previously a pharmacy intern at Ohio State's Medication Management Program (OSU-MMP). She received her bachelor of science degree in health science with a minor in public service from Long Island University.
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