There’s another type of prescription drugs, besides opioid painkillers, that’s involved in thousands of drug overdose deaths in the US every year.
The drugs are benzodiazepines, which are widely known by their brand names Xanax and Valium and commonly prescribed to help treat anxiety. These drugs were involved in nearly 9,000 overdose deaths in 2015, according to federal data. But there’s a catch: Such overdoses seem to be very closely tied to the opioid epidemic, with the majority of benzodiazepine overdose deaths involving both benzodiazepines and opioids.
A new study published in BMJ looked at just how much the concurrent use of these two drugs increases the risk of overdose versus the risk of only using opioids. Drawing on a huge sample of nearly 320,000 patients who were continuously enrolled in private health insurance plans from 2001 and 2013, researchers compared those who were prescribed just opioids versus those who were prescribed both, and what their additional risk of an emergency room visit or inpatient admission was in the period they were prescribed both.
The study found that among all opioid users, concurrent use of benzodiazepines more than doubled the risk of an emergency room or inpatient visit for a drug overdose.
The study also found that eliminating concurrent benzodiazepine and opioid use could reduce the risk for an opioid overdose–related emergency room or inpatient visit by 15 percent. If that reduced risk applies to overdose deaths as well, eliminating concurrent opioid and benzodiazepine use could have prevented up to 2,630 opioid painkiller–related overdose deaths in 2015.
Keith Humphreys, a drug policy expert at Stanford University and one of the authors of the study, said this reveals an underappreciated policy lever for reducing drug overdoses: making sure patients prescribed to opioids aren’t also prescribed to benzodiazepines, and vice versa. “Even if we didn’t change opioid prescribing at all, the data here suggest that we could cut overdoses dramatically just [by] getting prescribers to not put people on a benzodiazepine at the same time,” Humphreys said.
Yet the study suggests the opposite has happened. From 2001 to 2013, co-prescriptions to opioids and benzodiazepines among the studied pool of patients increased from 9 percent to 17 percent — a nearly 89 percent jump.
For some patients, eliminating these co-prescriptions could involve some tough trade-offs. If someone genuinely suffers from pain and anxiety, doctors and patients will need to work out which condition is more important to treat and which one can be treated with alternatives — to avoid a potentially deadly overdose. (Hopefully while keeping in mind that there’s no good scientific evidence that opioids can treat chronic pain, so opioids aren’t the right treatment for chronic pain in the first place.)
There are some caveats to the study. For one, emergency room visits and inpatient admissions for opioid overdoses likely aren’t a perfect one-to-one proxy for overdoses that didn’t involve a trip to a doctor. The study also only looked at legally prescribed opioid painkillers and benzodiazepines, missing the effects of concurrent use of illegally obtained pills or drugs. And since the research relied on patients who were continuously insured throughout the study period, it’s possible the findings don’t exactly apply to people with spottier coverage. (Although sensitivity analyses in the study for people who had lapses in insurance produced similar results.)
Finally, since the study looked at correlation (not causation), it’s possible that it missed some other factor driving up overdose deaths among concurrent benzodiazepine and opioid users — perhaps, for whatever reason, these users may be more likely to misuse their drugs.
Still, it’s well established that benzodiazepine and opioids compound each other’s overdose risk. So it’s not really controversial to conclude that simultaneously using opioids and benzodiazepines dramatically increases the risk of drug overdose — or, conversely, that stopping the concurrent use of these two drugs could reduce the risk of overdose.
Given that the opioid epidemic has quickly turned into the deadliest drug crisis in US history, it’s important — and potentially lifesaving — for doctors and policymakers to at least consider the study’s findings.
For more on the opioid epidemic, read Vox’s in-depth explainer, the abridged explainer, or the maps and charts explainer.