Medication Effects on Driving Skills

Some common medications — including antidepressants, sleeping pills and pain relievers — can impair older people’s driving skills, a new study finds.

Many different classes of medications have been linked to the risk of driving problems, as anyone who has ever read the label warning "do not operate heavy machinery" might have guessed.

But the new study took a particularly rigorous approach to investigating the problem: following older adults for up to 10 years and evaluating their driving skills with annual road tests. And it turned out that those who used certain classes of medications had a higher risk of failing the road test at some point.

Importance  

Older adults are increasingly prescribed medications that have adverse effects. Previous studies have found that an increased risk of car accidents is associated with the use of certain medications.

Aim  

To determine whether specific medication classes were associated with decreased performance as assessed by a standardized practice test in a community sample of cognitively healthy older adults, to evaluate additional associations of poor performance on the practice test with comorbid medical conditions and demographic characteristics. , and to test the hypothesis that certain specific medication classes (antidepressants, benzodiazepines, sedatives or hypnotics, anticholinergics, antihistamines, and nonsteroidal anti-inflammatory drugs or acetaminophen) would be associated with an increased risk of impaired driving performance over time.

Design, environment and participants  

This was a prospective cohort study of 198 cognitively healthy adults aged 65 years or older with a valid driver’s license who were followed annually, with continuous enrollment.

Data were collected from participants in St Louis, Missouri and neighboring Illinois who were enrolled in the Knight Alzheimer’s Disease Research Center. Data was collected from August 28, 2012 to March 14, 2023 and analyzed from April 1 to April 25, 2023.

Participants with healthy cognition, defined as a clinical dementia rating score of 0 at baseline and subsequent visits, who had clinical information, neuropsychological data, practical tests, and self-reported medication were included.

Exposure  

Use of medications potentially harmful to the driver.

Main results and measures  

The primary outcome measure was performance on the University of Washington practical exam (pass or marginal/fail). Multivariable Cox proportional hazards models were used to evaluate associations between potentially harmful driver medication use and road test performance.

Results 

Of the 198 adults included (mean [SD] baseline age, 72.6 [4.6] years; 87 women [43.9%]), 70 (35%) received a marginal/fail score on the practical test during a mean (SD) follow-up up to 5.70 (2.45) years.

Any use of antidepressants (adjusted hazard ratio [aHR], 2.68; 95% CI, 1.69-4.71), serotonin-norepinephrine reuptake inhibitors (aHR, 2.68; 95% CI , 1.54-4.64), sedatives or hypnotics (aHR, 2.70; 95% CI, 1.54-4.64); 95% CI, 1.40-5.19) or nonsteroidal anti-inflammatory drugs (aHR, 2.72; 95% CI, 1.31-5.63) was associated with an increased risk of receiving a grade of marginal/failed in the practical test compared to the control individuals.

In contrast, participants taking lipid-lowering agents had a lower risk of receiving a marginal/fail rating compared to control individuals.

Conclusions and relevance  

In this prospective cohort study, specific medication classes were associated with an increased risk of poor performance on practical tests over time. Doctors should consider this information and advise patients accordingly when prescribing these medications.

Comments

When older people took antidepressants, sedatives/hypnotics (sleeping medications), or nonsteroidal anti-inflammatory drugs (NSAIDs), they were almost three times more likely to get a failing or "marginal" grade than non-users.

The findings do not prove that medications are to blame, said lead researcher Dr. David Carr, a geriatric medicine specialist at Washington University School of Medicine in St. Louis. It can be difficult, he said, to draw a direct line between a particular medication and decreased driving skills: Is it that medication, the medical condition it’s treating, or another medication an older adult is taking?

However, in this study, Carr and her colleagues were able to take into account many factors, including participants’ medical conditions, memory and thinking skills, vision problems, and whether they lived in more affluent or disadvantaged neighborhoods. And certain groups of medications were still linked to worse driving performance.

Beyond that, Carr said, many of the drugs in question are known to act on the central nervous system, with potential side effects, such as drowsiness and dizziness, that could affect driving.

"The bottom line is we need to pay attention to this and counsel our patients," Carr said, adding that he doubts this is happening routinely.

Unfortunately, he added, during busy, time-limited doctor visits, discussions about medication side effects can fall by the wayside. That’s where patients need to be proactive, Carr said: asking questions about possible side effects when getting a new prescription. And if you wonder if your slowness or other symptoms could be due to a medication, talk to your healthcare provider.

"We wouldn’t want anyone to stop taking their medications on their own," Carr emphasized. "Talk to your healthcare provider about any changes."

Jake Nelson, director of traffic safety research and advocacy at the nonprofit AAA, echoed that point. The good news, Nelson said, is that his doctor could make some changes, such as switching to a different medication or adjusting the dosage or time of day a particular medication is taken. "Don’t feel like a burden by asking these questions," said Nelson, who was not involved in the study. "It’s about putting your health and safety first."

However, he also highlighted the role of the pharmaceutical industry in addressing the issue. There are better ways, Nelson said, to alert drug users about the risk of driving problems, which is often hidden in the "fine print."

The study, published September 29 in JAMA Network Open , involved 198 adults who were 73 years old, on average, at the beginning. None had signs of cognitive impairment (problems with memory, judgment, or other thinking skills).

Study participants underwent annual checkups, including a practical test with a professional driving instructor, for up to 10 years (about five years, on average). During that period, 35% received a failing and marginal grade on the practical exam at some point.

Older people taking antidepressants, sleeping pills or NSAIDs were at higher risk. The odds were higher for those taking antidepressants or sleeping medications: Between 16 and 17 percent had poor road performance per year overall. That compares with rates of 6% to 7% of their peers who don’t use those medications.

There were a couple of surprises , Carr said. The researchers found no link between antihistamines or anticholinergic medications and driving performance in older people.

Antihistamines are known to cause drowsiness in their users. Anticholinergic medications are used to treat a variety of conditions, from overactive bladder to chronic obstructive pulmonary disease (COPD) and Parkinson’s symptoms. They can cause side effects such as sedation and blurred vision.

But, Carr said, it’s possible that the older drivers in this study were using newer, non-drowsy antihistamines or that there were too few people taking anticholinergics to detect a significant effect.

Regardless of what medications they are using, Carr said older adults should talk to their doctor about any red flags, such as feeling drowsy or having a slower reaction, or having been "in danger" on the road.