Prescription data alone underestimated how many patients combined opioids and benzodiazepines, an analysis of Quest Diagnostics drug test data indicated.
Among a selected sample of patients whose drug test indicated concurrent benzodiazepine and opioid use, 64% had at least one benzodiazepine or opioid that was not prescribed, according to Quest researcher Leland McClure, PhD, and colleagues in a poster presentation at the 2018 PAINWeek conference.
“Clinicians need to be aware if their patients are using potentially dangerous combinations of drugs like benzodiazepines and opioids,” McClure told MedPage Today. “Because state-based prescription drug monitoring programs are limited to drugs prescribed, more effective detection of drug use is achieved by supplementing the prescribed drug database information with objective methods like drug testing.”
Benzodiazepines can increase the respiratory depressant effects of opioids: a recent review of health claims data showed that among opioid users, concurrent use of benzodiazepines more than doubled the risk of an overdose-related emergency room or inpatient visit. An estimated 23% of people who died of an opioid overdose in 2015 also tested positive for benzodiazepines. Both prescription opioids and benzodiazepines now carry FDA boxed warnings highlighting the dangers of using these drugs together.
The Quest Diagnostics analysis was based on 456,675 sets of test results from 276,953 patients in 50 states and the District of Columbia in 2017. Specimens were from patients who were prescribed at least one drug and who were tested for both opioids and benzodiazepines. All results included a report indicating what tested medication was prescribed and whether the prescribed drugs were detected in a specimen.
The laboratories performed drug testing with quantitative definitive tandem mass spectrometry; presumptive immunoassay screens preceded some of these tests. Immunoassays were performed using tests modified to detect target drugs exhibiting low cross-reactivity. “Our analysis defined relationship groups to ensure that drugs that could be metabolites of other drugs did not falsely inflate positivity rates,” McClure added.
In this cohort, 68.2% of specimens tested positive for opioids (including buprenorphine and methadone) and 29.2% tested positive for benzodiazepines. Overall, 20.6% of specimens tested positive for concurrent use of benzodiazepines and opioids. Of these patients, 36% had been prescribed both drug classes and 64% had at least one non-prescribed drug.
About 16% of specimens that tested positive for prescribed opioids also tested positive for non-prescribed benzodiazepines. Similarly, about 13% of specimens that tested positive for prescribed benzodiazepines tested positive for non-prescribed opioids.
“The extent of concurrent use of benzodiazepines and opioids, particularly non-prescribed use, cannot be determined by prescription drug database monitoring programs alone,” the researchers concluded.
The CDC recommends reviewing prescription drug monitoring program data to determine whether a patient is receiving combinations like opioids and benzodiazepines that may create a high risk for overdose, performing urine drug tests before starting patients on opioid therapy, and considering drug testing at least annually to assess for prescribed medications and illicit drugs.
The analysis has several limitations: With 68% of specimens testing positive for opioids, the results may be more representative of a monitored group of patients than the general population; also, complete prescribing information may not have been available.
This analysis was funded by Quest Diagnostics.
The authors are employees of Quest or consultants for the company; they reported having no other conflicts of interest.
Primary Source
PAINWeek
Source Reference: Gudin J, et al “Concurrent use of opioid and benzodiazepine:what the prescription drug monitoring database does not tell you” PAINWeek 2018; Abstract 44.
PAINWeek
Source Reference: Gudin J, et al “Concurrent use of opioid and benzodiazepine:what the prescription drug monitoring database does not tell you” PAINWeek 2018; Abstract 44.
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