Oxybutynin may speed cognitive decline in elderly patients, but is still prescribed.
Results from a new study suggest that a drug used to treat overactive bladder is highly prescribed in the United States, despite evidence that it may cause cognitive decline.
When taken orally, oxybutynin has been linked to cognitive impairment and dementia among elderly patients, according to a study published by JAMA Internal Medicine. The study found that the drug is still being prescribed in 27.3% of cases of overactive bladder.
Overactive bladder (OAB) is common among individuals aged 65 and older. Initially, patients may be treated through behavioral modifications, followed by antimuscarinic drugs, such as oxybutynin, according to the study. Antimuscarinic drugs are compounds that inhibit the muscarinic acetylcholine receptor.
Oxybutynin is the least expensive drug in this class, and is the preferred treatment for healthcare plans, including Medicare, regardless of scientific evidence that link the drug to cognitive decline, according to the authors.
In the new study, investigators gathered data from 1968 patients seeking treatment for OAB with antimuscarinic drugs.
Oxybutynin was prescribed to more than one-quarter of patients older than 65 who were seeking initial therapy for OAB. Although the FDA advises that patients treated with oxybutynin receive close monitoring for central nervous system side effects, only 9% of elderly patients received a neurologic exam, according to the study.
"We looked at a representative sample, but when you extrapolate to the US population the figures are huge,” said lead researcher Daniel Pucheril, MD. “We estimate that over the 6 years of our analysis, 47 million individuals in the USA were taking various types of antimuscarinic drugs for OAB, with around 55% of new prescriptions going to the over 65's.”
Lifestyle modifications and antimuscarinic treatments are the most common first-line treatment administered to 16% of adults with OAB. The authors note that a majority of elderly patients are insured through Medicare, which has a tiered formulary to minimize costs.
“Oxybutynin is the least expensive antimuscarinic drug available, but its pharmacologic properties may cause significant cognitive side effects in elderly persons,” Dr Pucheril said. “Despite evidence of these side effects, physicians are not commonly checking for cognitive effects in those using these medications.”
The authors suggest that physicians should review their prescribing habits and weigh the potential cognitive risks and benefits of prescribing oxybutynin to elderly patients. Physicians should also become better informed about alternative OAB therapies, which may treat the disorder, while preserving cognitive function.
"We're not saying that everyone should change from oxybutynin to another drug -- it still has its uses, and coming off the drug without medical supervision is not recommended. Nevertheless, doctors need to look closely at the levels of prescribing,” Dr Pucheril said. “More than anything else, the funding bodies have to make it easier for doctors to prescribe newer antimuscarinics which are much less likely to cause cognitive dysfunction."