benzos
Another type of prescription drug is implicated in thousands of opioid ODs each year.

The United States is in the grips of the worst drug overdose crisis ever, with prescription opioids and illicit opiates like heroin killing tens of thousands of people each year, but many of those people aren't dying from opioids alone. Another class of prescription drugs is too often involved.

Those drugs are the benzodiazepines—with brand names like Valium and Xanax—and are prescribed by the millions to treat anxiety, They can be deadly on their own, with federal data showing nearly 9,000 fatal benzo ODs in 2015. But here's the kicker: Nearly half of all fatal benzo ODs involve both them and opioids.

And a new study published in the British Medical Journal provides further evidence of the risks of doing benzos and opioids together. That study drew on a sample of more than 300,000 patients continuously enrolled in private health insurance plans between 2001 and 2013, and researchers looked at emergency room visits for drug overdoses among those prescribed only opioids versus those prescribed both opioids and benzos.

The results were dramatic: People prescribed both types of drugs had nearly double the risk of an ER or inpatient visit for a drug overdose. Based on the results, researchers estimated that cutting benzo prescriptions for opioid users reduced the risk of ER visits by 15%. If that figure holds true for overdose deaths, some 2,630 opioid-related overdose deaths could have been prevented in 2015 alone.

The policy implications are clear, said study co-author and Stanford University drug policy expert Keith Humphreys: Don't prescribe benzos to people being prescribed opioids.

"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.

That would require a real shift in prescribing practices. The number of patients in the study being prescribed both benzos and opioids nearly doubled between 2001 and 2013, from 9% to 17%.

Reducing co-prescriptions could be problematic for some patients. If they are suffering both pain and anxiety, they and their doctors will have to work together to decide which issue is most serious and which could be treated with alternatives. But making such tough choices could lead to a reduced risk of fatal overdose.

The BMJ study has its limits. It looked only at legally prescribed benzos and opioids, missing the effects of concurrent use of illicit drugs, and it looked only at ER and inpatient visits, not fatal overdoses. And it only demonstrated correlation, not causation. It's possible some factor other than co-prescribing was driving up overdose rates among study patients, but given that the overdose risks of mixing benzos and opioids are well established, suggesting that co-prescribing them results in increased overdoses is not exactly controversial.

Doctors can do their part to reduce the number of overdose deaths by reducing benzo and opioid co-prescribing, but since much benzo and opioid use occurs outside legal medical channels, users in non-medically supervised settings are also going to have to be keenly aware of the dangers of mixing those drugs. If they are, the evidence suggests they can save some lives.