By Cheryl Platzman Weinstock

(Reuters Health) - One in five drivers in a random survey had taken prescription drugs that could impair their driving ability, and most were on the road despite having been warned about the risks, a U.S. study found.

“This is the first large-scale study of prescription drug use at the roadside. It gives us direction if we want to improve our knowledge of how to better prescribe and dispense prescription drugs,” said lead study author Robin Pollini, associate director of the West Virginia University School of Public Health’s Injury Control Research Center in Morgantown.

“The interesting thing about this finding is how many of these people got some sort of warning about how their medicine could impair them, but they were still on the road,” said James Hedlund, an independent safety consultant with Highway Safety North in Ithaca, New York, who was not involved in the research.

“The big take away from this study is that physicians and pharmacists have to do a better job talking with patients about how any drug can impair a driver’s abilities,” Hedlund, a former National Highway Traffic Safety Administration (NHTSA) official, told Reuters Health in a phone interview.

As reported online October 31 in the Journal of Studies on Alcohol and Drugs, Pollini’s team analyzed data from the latest National Roadside Survey of Alcohol and Drug Use, 2013-2014, in which random drivers across 60 sites were asked about prescription drug use within the past 48 hours.

Nearly 20% of the 7,405 drivers who completed that part of the survey had used potentially dangerous medications, including sedatives, narcotics, antidepressants and stimulants - all of which can impair a person’s thinking and judgment - sometime in the past two days.

Among the drivers who answered the drug question, 8% had taken sedatives like Valium (diazepam), Xanax (alprazolam), Ambien (zolpidem) and Lunesta (eszopiclone), and 7.7% had taken antidepressants like Prozac (fluoxetine), Zoloft (sertraline) and Wellbutrin (bupropion). Narcotics like methadone, codeine, Vicodin (acetaminophen and hydrocodone) and similar prescription pain killers had been taken by 7.5%, and 3.9% had used stimulants like the ADHD medications Ritalin (methylphenidate) and Aderall (amphetamine).

Among those who used sedatives or narcotics, 85% said they received a warning from their healthcare provider or the medication label about possible impairment. However, just 63% of drivers using antidepressants and 58% of those using stimulants reported receiving warnings about their risk.

Asked if these drugs were potentially dangerous, study participants thought sleep aids, followed by morphine/codeine, most amphetamines and muscle relaxants were safe to take while driving. They thought use of ADHD medications was likely to cause a crash or result in legal ramifications, however.

Men were less likely than women to say they'd been warned about sedatives, researchers found. Night-time drivers were less likely than daytime drivers to report warnings about antidepressants and narcotics. Overall, black drivers were much more likely than non-Hispanic white drivers to report being warned about the risks of a prescription drug.

In an accompanying commentary. Dr. Benedikt Fischer of the Center for Addiction and Mental Health in Toronto notes that “prescription medications are considered therapeutic and thus seen as shielded from causing risk to individuals or society.” But this thinking is “misguided,” he writes, since many drugs have the potential to cause injury and mortality.

Driving while on prescription or illicit drugs has become increasingly common, whereas driving while intoxicated has declined more than three quarters since 1973, according to the NHTSA survey.

Drugs were detected more frequently than alcohol among fatally injured drivers in 2015, according to a report this year from the Governors Highway Safety Association, a non-profit organization of state highway safety offices. Forty-three percent of fatally injured drivers tested positive for drugs.

Pollini told Reuters Health in a phone interview that she hopes her research will remind physicians and pharmacists to have in-depth talks with their patients about the potential risks of medications. The U.S. should also take “solid steps” to improve warning label practices, she said, adding that many European countries have introduced color codes to drug labeling to increase patient safety.

SOURCES: http://bit.ly/2iqyA5B and http://bit.ly/2iU6CmC

J Stud Alcohol and Drugs 2017.