Combining opioids and benzodiazepines may increase your odds of ending your night in the ER, researchers at Stanford University recently concluded. And if you've ever taken either drug, that's probably not the most shocking news. "It's not a secret," says Eric Sun, the study's co-author. "It's well known that these drugs are a dangerous mix."
What is surprising from the study, published in the BMJ, is how often the two drug types are prescribed together despite the known risk they present.
Sun and his collaborators examined the histories of more than 300,000 privately insured Americans who were prescribed an opioid painkiller sometime between 2001 and 2013. In 2001, only nine percent of opioid users also received a script for a benzodiazepine, like Xanax or Klonopin, a drug category often used to treat anxiety or insomnia. By 2013, concurrent use of opioids and benzos increased to 17 percent, an uptick of 80 percent.
The study found that use of both drugs at once was associated with a substantially higher risk of admission to an emergency room or inpatient program for an overdose than using opioids alone. In fact, nearly 30 percent of fatal overdoses blamed primarily on opioids also involved benzodiazepines.
The two categories comprise the bulk of America's most often abused prescription drugs. Opioid abuse has crept up on the US over the past 20 years, killing more than 33,000 people in 2015 alone (compared to 4,030 in 1999). OD deaths from benzodiazepines are comparatively small, claiming 8,791 Americans in 2015. But like opioid deaths, they are on a dramatic rise, having undergone an eight-fold increase from 1,135 deaths in 1999.
Opioid fatalities are caused by the drugs' effect on the central nervous system's control of breathing. Benzos also suppress air intake. "There is a synergetic effect," Sun says. "Take them together and some of the moving parts might cause a shutdown in breathing." Last year, the Food and Drug Administration put a "black box" warning on the medications, noting the potentially lethal effects of drug interaction.
So why are doctors prescribing the two together if it presents such a hazard? Well, they might not be, Sun says.
"There's no central database for what prescriptions you're on," he says. "Two doctors might not know what you are taking." Unless they are in the same health network, the primary-care physician who prescribed Vicodin is probably not communicating with the psychiatrist who gave the same patient a script for Valium. Pharmacists might not know about the concurrent use, either, Sun says. "Walgreens doesn't communicate with CVS. Only your insurer knows for sure what drugs you are on."
That's why he recommends a system by which insurance companies warn patients of bad drug interactions. There's also a simpler solution, he adds. "If you, the patient are on both drugs at the same time, make sure your doctor knows."
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