A drug linked to a raised risk of dementia is taken by millions of older Americans who have an overactive bladder, researchers say.
More than one-quarter of patients with the urinary problem had been prescribed the drug oxybutynin (Ditropan), an international team of investigators found.
Yet, “oxybutynin is a particularly poor drug for overactive bladder in elderly patients,” said study lead author Dr. Daniel Pucheril, a urologist at Henry Ford Hospital in Detroit.
Prior studies have linked the drug to thinking problems and increased risk of dementia in older people, possibly because of the way it affects brain chemicals, he said.
“It’s a great and effective drug for younger patients, but is a risky drug for older patients,” Pucheril said. It boosts dementia risk even when not taken indefinitely, he said.
Alternatives exist but they’re more expensive and may not be covered by insurance, at least initially, the study authors explained.
For instance, “most Medicare Part D plans have a tiered drug formulary, which means that patients must try and ‘fail’ oxybutynin before they will be eligible for the newer generation of [so-called] antimuscarinic medications,” Pucheril said.
Also, there’s debate over the safety of alternatives.
The Urology Care Foundation estimates 33 million Americans have an overactive bladder. These people often need to urinate urgently, frequently or both. Some also suffer from incontinence.
Non-medical treatments — including changes in diet, exercises and scheduled urination — are usually the first line of treatment. Surgery is sometimes an option, as are prescription antimuscarinic medications like oxybutynin.
To determine how often oxybutynin is prescribed to seniors, researchers examined 2006-2012 statistics from the U.S. National Ambulatory Medical Care Survey. The investigators focused on about 2,600 patients aged 65 and older who received prescriptions for oxybutynin or similar medications for overactive bladder. The drug was prescribed 27 percent of the time for those patients.
Only 9 percent of those who took the drug underwent a neurological exam, even though the U.S. Food and Drug Administration recommends monitoring these patients for any signs of brain problems, the researchers pointed out.
“We cannot tell if patients are being monitored for neurologic problems in other ways,” Pucheril noted.
In addition, some doctors — but certainly not all — may be unaware of the mental side effects of oxybutynin, the researchers said.
Although alternatives exist, not everyone agrees they’re safer. A 2011 paper in Current Urology Reports described darifenacin (Enablex), tolterodine (Detrol), trospium (Sanctura) and solifenacin (Vesicare) as “having little or no risk” of oxybutynin-like effects on the brain.
However, urologist Dr. David Staskin contended that “no one has ever shown that tolterodine, darifenacin, or solifenacin is safer.” He said only trospium has been shown to not penetrate very deeply into the central nervous system.
“The problem here is whether it would eliminate the risk to switch everyone to another antimuscarinic,” said Staskin, an associate professor of urology at Tufts University School of Medicine in Boston.
According to Pucheril, other possible options include a newer class of medications called beta-3 agonists, neuromodulation (zapping nerves with electricity), and Botox delivered into the bladder.
A Canadian specialist noted that immediate-release oxybutynin is the form most linked to dementia. “Older patients on the drug should consider a review with their clinician,” said Dr. Adrian Wagg, director of geriatric medicine at the University of Alberta.
There’s no evidence that a family history of dementia adds to the drug’s risk, he said, or that people who already have dementia will face the same added risk as others.
The study was released Monday at the European Association of Urology conference in London. Research presented at meetings should be considered preliminary until published in a peer-reviewed journal.
One of the study authors reported receiving a grant from the pharmaceutical company Genentech via the American Society of Clinical Oncology.