The results showed that oxybutynin was prescribed in 27.3% of the elderly population who were receiving a prescription for an antimuscarinic for the first time.
Importantly, oxybutynin is the least pharmacologically appropriate of the antimuscarinics, Dr Meyer said. While the study did not explore why physicians opted for oxybutynin rather than other antimuscarinic agents for older OAB patients, he believes it’s probably due at least in part to Medicare policy.
Tiered Medicare formularies require patients to start with oxybutynin, which is a less expensive, generic antimuscarinic.
He also pointed out that only 9% of elderly patients underwent neurologic assessment at the time that they were initially prescribed oxybutynin, despite the fact that the US Food and Drug Administration recommends that patients initiating oxybutynin therapy be closely monitored for central-nervous–system side effects.
Cognitive impairment is an especially worrisome adverse effect in older patients, since even modest cognitive impairment, such as memory lapses and mild confusion, may interfere with the patient’s ability to live independently, Dr Meyer pointed out. What’s more, medications that increase cognitive impairment and cumulative anticholinergic load can increase the risk of falls in elderly patients.
Finally, he said that the investigation “is the first population-based study showing both the alarming rate of oxybutynin prescription and the lack of a proper safety net for a growing and vulnerable elderly population.”
Meyer C, Pucheril D, Karabon P, et al. “Antimuscarinic Use in the Elderly: A Poisoned Apple?” 32nd Annual European Association of Urology Congress in London, UK. Abstract number 533.