FRIDAY, Feb. 15, 2019 (HealthDay News) -- The damage wrought by the opioid epidemic has spread to America's highways, with the percentage of fatal car crashes involving a driver who was high on the powerful painkillers tripling in the past 25 years.
Study co-author Dr. Guohua Li said the finding "adds important information for understanding the ripple effects of the opioid epidemic, particularly its adverse effect on driving safety."
And it suggests that the "use of prescription opioids plays a significant role in the causation of fatal motor vehicle crashes," he added.
Li is director of the Center for Injury Epidemiology and Prevention at Columbia University Medical Center, in New York City.
Li explained that prescription opioids (such as OxyContin) "are potent pain medications that can cause drowsiness, nausea, and impaired cognitive functions and psychomotor skills, including reduced reaction time, alertness, attention and concentration."
On average, he said, the impact that prescription opioids have on driving is comparable to that of alcohol consumption that clocks in at a blood alcohol concentration (BAC) reading of 0.05 percent. In most states, a BAC reading of 0.08 warrants a "driving under the influence" (DUI) conviction.
Regardless, Li stressed that when an individual takes an opioid and gets behind the wheel, their driving behavior is inevitably less safe. In fact, the study showed that use of prescription opioids more than doubled the risk of causing a fatal two-car crash.
The findings stem from a review of data on more than 18,000 deadly two-car crashes that occurred across the United States between 1993 and 2016.
Among those accidents, 55 percent of the driving errors committed by drivers who tested positive for prescription opioids involved the failure to stay in their lane.
Li described that as "a particularly dangerous driving error." And the researchers determined that it was, in fact, the key factor in more than four in 10 fatal two-car crashes, making it the most common cause of deadly auto accidents.
Booze is still a major player in car accidents, however. The team found that compared with drivers who were cleared of responsibility for instigating an accident, at-fault drivers were more likely to test positive for alcohol. Nearly three in 10 at-fault drivers tested above the legal drinking limit, compared with just one in 10 among no-fault drivers.
"Although alcohol involvement in fatal crashes has declined slightly in the past decade, it remains the most important substance that impairs driving and causes injuries and fatalities," Li said. He noted that alcohol-impaired driving is currently about six times more common than driving while high on prescription opioids.
But opioid use doubled the risk for a deadly two-car collision whether or not any of the drivers involved had been drinking as well, the researchers added.
As to how to confront the issue going forward, Li acknowledged that testing drivers for opioid use is more difficult and more expensive than testing for drinking.
"It is also more difficult to detect drug-impaired driving than alcohol-impaired driving through field sobriety tests," he said.
"But law enforcement is making effort to tackle the drugged driving problem," Li noted. "For example, many states are expanding their drug recognition expert programs, which would train more police to become certified field evaluators of driving under the influence of drugs."
On the drivers' side, Li said it's important that prescribing physicians "take into consideration the adverse effect on driving safety of pain medications, particularly opioid analgesics."
J.T. Griffin, chief government affairs officer for Mothers Against Drunk Driving (MADD), suggested that the findings are to be expected.
"With the rising use of opioids, it is not surprising that there is an increase in the number of drivers with opioids in their systems," he said.
"Any drug that causes drowsiness, slows reaction times, or affects judgment and mobility in any way is a threat to public safety," Griffin noted. "It's important that people do not drive anytime they are drinking or using any kind of impairing substance."
Meanwhile, Griffin suggested that police officers should be encouraged to get better drug detection training, and to deploy so-called "sobriety checkpoints" to catch driver impairment, whatever the underlying cause may be.
The report was published online Feb. 15 in JAMA Network Open.
There's more on opioids and driving at the U.S. Drug Enforcement Administration.