Toxicology Topics: Drug Levels for Buprenorphine: Efficacy, Diversion, and Compliance

Drug monitoring is a nearly universal component of treatment for patients with opioid use disorder on medication therapies, as is drug testing in general in clinical addiction medicine. To apply clinical drug testing appropriately for buprenorphine, providers need to understand the various methods of testing, specifically their accuracy, cost, limitations, and the interpretation of results for different matrices (e.g., urine, hair, saliva). In addition to understanding basics about drug testing, such as whether false positives or negatives can occur for a specific analyte and how specimen validity testing is performed, providers should be aware of the array of testing options at their disposal, including the qualitative analysis of urine and saliva, confirmatory testing, and specific levels of buprenorphine, metabolites, and naloxone. Additionally, there are nuances in the interpretation of buprenorphine levels, including total vs. differentiation of free and conjugated levels for buprenorphine and its metabolites and the creatinine normalization of levels. Understanding test characteristics, the utility of ordering different analyte combinations, and the correct interpretation of results is essential if applying this to practice. The pharmacokinetics of buprenorphine and naloxone can be complex, but understanding this is vital to quantitative laboratory analysis; reviewing these concepts will allow providers to understand and interpret the various buprenorphine assays afford additional opportunities to support patients with treatment of buprenorphine for opioid use disorder.The discussion will focus on the utility of the individual concentrations and ratios of buprenorphine and metabolites and whether they can be interpreted to indicate compliance, misuse, or diversion of buprenorphine formulations. We will also discuss whether levels are patient-specific and if reference ranges are generalizable to a population. The presence and levels of naloxone in these assessments will be addressed as well. Given that quantitative buprenorphine levels are not routinely available in all treatment settings, we will cover the reliability and interpretation of buprenorphine determined by urine immunoassay tests and from oral fluid or saliva testing. We will also provide an overview of published research and reports on use of drug testing in general and on the interpretation of buprenorphine results in drug testing identifying resources available to providers to assist with analysis and interpretation.This session will address these topics through a combined, interactive case-based and didactic session that will be provided by a panel of medical toxicology and addiction medicine expert faculty that allows for active audience engagement via question and answer. . We will discuss the different buprenorphine and naloxone tests, the interpretation of results, impact on patient management, and review the available literature in this area.