Buprenorphine for OUD May Also Mitigate Risk With Concomitant Benzo, Z-Drug Use

Michael Vlessides

March 16, 2021

Buprenorphine for the treatment of opioid-use disorder (OUD) may also mitigate the risk associated with concomitant benzodiazepine and Z-drug use, which is frequent in this patient population, new research suggests.

A case-crossover study of more than 20,000 participants with OUD showed that drug treatment days in which benzodiazepines and Z-drugs were taken were associated with an 88% increase in nonfatal overdose; buprenorphine appeared to reduce this risk by almost 40%.

"One of our two primary findings is that patients with opioid use disorder can still benefit substantially from buprenorphine treatment, even if they have benzodiazepines on board," lead author Kevin Xu, MD, a resident at the Washington University School of Medicine, St. Louis, Missouri, told Medscape Medical News.

The other key finding was that "not all benzodiazepines are equal" and that some are associated with higher risk than others, Xu added.

"If anything, patients who are on buprenorphine and benzodiazepines do not necessarily need to be abruptly tapered off their benzodiazepines. Our data actually demonstrate that there are safe avenues for them," he added.

The findings were published online March 3 in the American Journal of Psychiatry.

Cloudy Relationship

Buprenorphine is commonly used to treat patients with OUD because of its ability to decrease all-cause mortality. However, up to 30% of these patients also take benzodiazepines for comorbid mood and anxiety disorders, Xu noted.

In addition, recent research shows that benzodiazepine/Z-drug use is associated with a variety of potential adverse effects, including respiratory depression, overdose, and addiction risk.

The relationship between benzodiazepine use and buprenorphine treatment outcomes is poorly characterized in individuals with OUD. Although some studies suggest benzodiazepines may enhance retention in buprenorphine maintenance treatment, others suggest a link to increased adverse events, including all-cause mortality, drug-related poisonings, and accidental injury–related emergency department visits.

In addition, there has been little research on the potential adverse effects associated with use of selective benzodiazepine receptor modulators in patients with OUD. These so-called Z-drugs include zolpidem, zaleplon, and eszopiclone.

Nevertheless, previous research in the general population shows that these medications have a range of adverse effects similar to those of benzodiazepines, with comparable dose-response effects on all-cause mortality.

"The challenge for any clinician is that many patients who are addicted to opioids are also polysubstance users," said Xu. "There are so many hopeful articles regarding the benefits of buprenorphine treatment in opioid use disorder patients, but it seems like the individuals with polysubstance use are largely ignored in the setting of the opioid epidemic.

"And this is really the back story that got me inspired to study this particular topic," he added.

Improve, Nullify, or Reverse?

Given these questions, the researchers set out to quantify the odds of nonfatal drug-related poisoning, including overdoses, associated with benzodiazepine or Z-drug use by patients with OUD who were also taking buprenorphine.

"While the drug-related poisoning variable encompasses opioid overdoses, we used a broad definition per CDC guidelines to also include other types of drug overdoses ― including poisoning events involving stimulants, overdoses involving sedatives, and overdoses involving psychotropic prescription drugs" that are commonly used by patients with OUD, said Xu.

They also wanted to determine whether the use of benzodiazepines or Z-drugs would improve, nullify, or reverse the protective effect of buprenorphine. The researchers also evaluated whether different sedative and hypnotic subtypes of these drugs were associated with different poisoning risks.

The researchers analyzed pharmaceutical claims data from 304,676 individuals (aged 12 to 64 years) in the IBM MarketScan Commercial and Multi-State Medicaid Databases. All had received buprenorphine treatment for OUD between January 1, 2006, and December 31, 2016.

Buprenorphine use was converted to a daily milligram dose and was classified as either >12 mg or ≤12 mg, because previous research suggests there may be differences in treatment retention associated with this dose. Given the case-control nature of the investigation, patients who did not experience a drug-related poisoning were excluded from the analysis.

The study's primary unit of observation was person-days, which were those days during which patients were enrolled in a health insurance plan. Participants were evaluated for 1 year before their first drug-related poisoning and 1 year after their first such poisoning. The primary outcome was nonfatal drug-related poisonings, including overdoses. The primary exposure was determined on the basis of benzodiazepine or Z-drug prescriptions.

The daily dose of benzodiazepines or Z-drugs was standardized as a function of diazepam-equivalent milligrams. Doses were classified as either high dose (diazepam-equivalent mg dose >30 mg) or low dose (≤30 mg). The drugs were also distinguished on the basis of their pharmacologic properties, such as whether they were short acting or long acting.

37% Risk Reduction

Of the original cohort of 304,676 patients with OUD, the study's final analytic sample included 23,036 patients (mean age, 30 years; 51% men), representing 14,213,075 person-days of insurance coverage. Of these, 2,210,927 person-days (15.6%) entailed claims for buprenorphine (mean daily dose, 15.4 mg; SD, 7.31 mg).

A total of 474,181 person-days included claims for benzodiazepines or Z-drugs with concurrent buprenorphine treatment. The mean daily dose of any benzodiazepine or Z-drug was 23.4 diazepam-milligram equivalents. The mean daily dose of short-acting benzodiazepines, long-acting benzodiazepines, and Z-drugs was 25.3, 31.3, and 4.9 diazepam-milligram equivalents, respectively.

Buprenorphine treatment days were associated with a 37% lower chance of drug-related poisoning (95% CI, 0.60 – 0.66) in comparison with nontreatment days. On the other hand, the odds of poisoning increased by 81% on days on which patients were treated with Z-drugs or benzodiazepines (95% CI, 1.73 – 1.91).

Interestingly, individual analyses showed that benzodiazepine and Z-drug treatment days were associated with increased odds of poisoning events (odds ratio [OR], 1.29; 95% CI, 1.19 – 1.39). Odds of poisoning events on benzodiazepine-only treatment days, on the other hand, were markedly lower (OR, 1.88; 95% CI, 1.78 – 1.98).

Subgroup analyses revealed that both short-acting and long-acting benzodiazepine treatment days were associated with comparably elevated odds of drug-related poisoning (OR, 1.86 and 1.68, respectively). High-dose benzodiazepine treatment days were associated with higher increased odds of a poisoning event (122%) in comparison with low-dose treatment days (78%).

High-dose, but not low-dose, benzodiazepine or Z-drug treatment was linked to increased poisonings when the drug was taken concurrently with buprenorphine (OR, 1.64; 95% CI, 1.39 – 1.93). However, the risk was still lower than the risk associated with taking the agents without concurrent treatment with buprenorphine (low-dose OR, 1.69; high-dose OR, 2.23).

"Not All Benzodiazepines Are Bad"

Xu noted that the findings have potentially important implications for clinical practice, beginning with the dose-dependent relationship between benzodiazepine/Z-drug use and drug-related poisonings among individuals with OUD. This indicates that lowering doses or shortening treatment duration may reduce risk, he said.

Similarly, the lower risk associated with long-acting benzodiazepines relative to short-acting beonzodiazepines – as well as the substantially lower risk associated with Z-drugs compared with either short- or long-acting benzodiazepines – suggests that switching from benzodiazepines to long-acting agents or Z-drugs may lower the risk for overdose, he added.

"Clinicians are often challenged by patients with opioid use disorder who are also on benzodiazepines or Z-drugs. There's an inclination to say no to them, because they're too high risk to start buprenorphine maintenance, or abruptly taper the benzodiazepines, which can be very destabilizing," he noted.

"Our data show that people on benzodiazepines can absolutely receive buprenorphine and still get some benefit," Xu said. "In addition, not all benzodiazepines are bad for these individuals. There are safer formulations and safer doses, too."

However, he added, he would not initiate benzodiazepine treatment if he didn't have to, especially long-term treatment.

"One of the messages from our data is that this clearly contributes to higher overdose risk. But we often inherit patients who already have benzodiazepines on board, so we need to figure out what to do. That is the question that nobody had really clearly addressed prior to this study," Xu concluded.

Vigilance Needed

Commenting on the findings for Medscape Medical News, Jerrold F. Rosenbaum, MD, Stanley Cobb Professor of Psychiatry, Harvard Medical School, Boston, Massachusetts, urged caution when combining benzodiazepines with opioids.

"There are situations where you need to be circumspect about the use of benzodiazepines, and that's clearly when people are being prescribed them in combination with other drugs that could be either sedating or respiratory depressant," said Rosenbaum, who was not involved with the research.

"This paper reminds us that physicians need to be particularly vigilant about situations where patients might be combining the two agents," he added.

Rosenbaum noted that patients who are using more medication than prescribed are at risk "for not appreciating the synergy" between the two treatments in terms of adverse events such as respiratory depression.

In addition, "if they're intending to do themselves harm, the lethality of an overdose will be certainly far more than the benzodiazepines or opiates alone," he said.

Another potential challenge for clinicians are situations in which patients are taking benzodiazepines for preexisting conditions that also require opiates. "Then you have to use special vigilance and try to use lowest doses to reduce the total burden of medication to minimize the potential risk," said Rosenbaum.

The study was funded by the National Institutes of Health. Xu has reported no relevant financial relationships.

Am J Psychiatry. Published online March 3, 2021. Abstract

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