(Reuters Health) - - Many older drivers are taking multiple medications that may increase the risk of car crashes, a new U.S. study suggests.

Half of older drivers interviewed for the AAA Foundation for Traffic Safety study were taking seven or more medications, and one quarter were taking 11 or more, researchers found.

And nearly one in five were taking medications the American Geriatrics Society has called potentially inappropriate medications, or PIMs. According to the society, these medications should be avoided by seniors because they have very limited benefit, pose excess harm, or both.

Most of these PIMs, which include benzodiazepines and some antihistamines, have been shown to cause impairments, such as blurred vision, confusion, fatigue or incoordination. Other research has shown that these medications can raise the risk of a crash by up to 30 percent, the AAA Foundation researchers note in their report.

Currently, 42 million adults age 65 and older are driving on U.S. roads and the number is expected to increase substantially over the next decade, according to AAA.

“The good news is that a lot of things can be done about this,” said Jake Nelson, AAA director of Traffic Safety Research and Advocacy. “By working shoulder to shoulder with healthcare providers and pharmacists we can mitigate the risks by letting older drivers take the medications they need while allowing them to drive safely. The bad news is that patients are not having the necessary conversations with their doctors and pharmacists.”

In fact, an earlier study found that “when it came to families discussing driving behaviors with older members, 83 percent reported they had never had a conversation,” said Tara Kelley-Baker, data and information group leader at the AAA Foundation for Traffic Safety in Washington, DC. Another earlier study found that fewer than 2 in 10 older patients said they had received a warning from healthcare providers about how their prescriptions might impact their driving.

For the new report, researchers from the AAA Foundation and study sites in five states analyzed data from 2,949 seniors participating in the AAA LongROAD study. When the seniors enrolled, they were aged 65 to 79 and were asked to put all their medications, including vitamin and food supplements and over-the-counter drugs, in a bag and bring them to be reviewed.

Participants brought a total of 24,690 medications to the review sessions. Overall, while 3 percent of participants took no medications and 10 percent took two or fewer, 10 percent took 16 or more and 1 percent took 26 or more.

Seventy-three percent of participants took at least one drug for heart disease and 70 percent took a drug that affects the central nervous system.

Of particular concern to the researchers were the medications that were potentially inappropriate for older adults, which would include drugs that impair physical or mental function, such as narcotic pain medications, anti-anxiety medications like benzodiazepines and sleep aids. Along with the potential negative effects on driving ability, these medications are also associated with adverse effects, such as hip fractures, depression and incontinence.

The researchers also note that the odds of an older adult falling are 6 times higher if they are using 10 or more medications.

The bottom line on this study “is it confirms what a lot of internists and geriatricians suspect,” said Dr. Zaldy Tan, an associate chief of geriatric medicine at the David Geffen School of Medicine at the University of California, Los Angeles.

A big part of the problem is that older people often see multiple physicians, said Tan, who was not involved in the new research. Their physicians often don’t know about all the medications a patient is taking, just the ones they themselves prescribed.

Tan suggests older patients bring a list of all their medications, as well as the reason each was prescribed, to their primary care physician. “If they are taking more than 10 then I would start looking very carefully to see if any of them can be taken away,” Tan said.

The foundation also offers a website (www.roadwiserx.com) where users can check the effects and interactions of the medications they’re taking.

SOURCE: bit.ly/2P4lr0x AAA Foundation for Traffic Safety, online November 28, 2018.