Observations on the effects of buprenorphine and methadone on illicit drug use.

OBJECTIVE: To determine if the agonistic effects of buprenorphine and methadone affect drug use. METHOD: Quantitative examination of urine drug concentrations of patients treated with buprenorphine and methadone. RESULTS: Patients on buprenorphine had less opioid and methamphetamine drug use than those on methadone. CONCLUSION: Patients on buprenorphine therapy appear to use less illicit drugs.

Monitoring buprenorphine in patients on medication-assisted treatment.

BACKGROUND: Buprenorphine is used for medication-assisted treatment of opioid dependence. PURPOSE: Monitoring of medication adherence involves testing of urine or oral fluid for the drug or its metabolite. METHODS: Quantitative results using liquid chromatography tandem mass spectrometer testing defined the excretion pattern of the drug and its metabolites. RESULTS: Frequency distribution curves of buprenorphine and norbuprenorphine describe the expected drug concentrations of patients on this medication. CONCLUSION: Urine and oral fluid drug testing can be used to monitor adherence in this population.

A Comparative Analysis of Two Commonly Used FDA-Approved Immunoassays for Fentanyl Detection.

BACKGROUND: Given the opioid epidemic, fentanyl screening in urine has become increasingly important. Immunoassays remain the most common screening methodology due to the high throughput and ease of integration into automated chemistry systems. The fentanyl ARK II from Ark Diagnostics is a widely used immunoassay, while a novel fentanyl assay called FEN2 by Lin-Zhi has become available on the Roche platform. Here, we evaluate and compare their performance. METHODS: Four hundred and thirty-four urine samples were analyzed for fentanyl across the Lin-Zhi FEN2 and ARK II assays on the Cobas c502 platform. Samples were analyzed immediately upon request for drug of abuse screening or frozen for subsequent analysis. For confirmation testing, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method with a limit of detection of 1 ng/mL for fentanyl/norfentanyl was used. Any sample with either fentanyl or norfentanyl above the LC-MS/MS cutoff was deemed positive. RESULTS: The ARK II had 11 false negatives and 7 false positives, while the Lin-Zhi FEN2 had 12 false negatives and 2 false positives. This resulted in ARK II having a sensitivity and specificity of 90.4% and 97.8% respectively, while Lin-Zhi FEN2 had a sensitivity and specificity of 89.5% and 99.4%. CONCLUSIONS: Both the ARK II and Lin-Zhi FEN2 immunoassays detected fentanyl well. Overall, the Lin-Zhi assay had slightly better specificity than ARK II, in our data set. While some discrepant results were observed between the 2 immunoassay systems, most occurred near the immunoassay detection cutoffs.

Letter to Editor: Observations of Deception in Urine Drug Testing.

OBJECTIVE: Determining deception in urine drug testing. Some of the patients undergoing urine drug tests have not taken the prescribed drug and attempt to deceive the laboratory test by placing the parent drug in the collection cup. METHODS: One of the ways to determine if this is occurring is to monitor the major metabolite of the drug. By using the metabolite/parent drug ratio this attempt at deception can be uncovered. RESULTS: Of the five drugs we examined, oxycodone, hydrocodone, buprenorphine, methadone, and fentanyl, we found buprenorphine to be the most prevalent drug to this type of deception. CONCLUSION: Deception can be identified using the metabolite/parent drug ratio.

Estimates of Drug Metabolism Using Drug Excretion Concentrations.

We propose that quantitative urine drug concentrations from LC-MS/MS measurements can be used to estimate zero and first order pharmacokinetics of the drugs oxycodone, hydrocodone, buprenorphine, methadone, and fentanyl. We observed the ratio of metabolite to parent drug could be used for this estimate. As the amount of observed parent drug increased, the metabolic ratio decreased, indicating a shift from first order to zero order metabolism. After making assumptions of bioavailability, percent of drug excreted into urine, we developed estimates of the saturating dosages for these drugs.

Changing Landscape of Fentanyl/Heroin Use and Distribution.

OBJECTIVE: To understand the geopolitics of the supply of fentanyl and heroin. RESULTS: In our practice, the percent of fentanyl positive drug tests increased from years 2016 to 2022, but heroin positive drug tests decreased by 80% in the same period. CONCLUSION: Fentanyl has replaced heroin as a street drug for opioid dependent drug users.

Interpretation of urine drug testing in pain patients.

BACKGROUND: Traditionally, urine drug screens have only been concerned with positive or negative results. Those results provide physicians treating patients for pain with chronic opioid therapy with information about medication compliance, use of nonprescribed medications, and use of illicit drugs. However, the analysis of urine for drugs offers additional information that, when compiled and accurately interpreted, may also be of great value to these doctors. PURPOSE: The aim of this article was to discuss the interpretation of urine drug tests and their application to pain physician practices. METHOD: We utilized a selection of recent articles on urine drug screening applicable to the pain patient population. RESULTS AND CONCLUSIONS: The article provides pertinent information about interpretation of urine drug testing, which is separated into six categories: which drugs and metabolites to test for; which analytical cutoffs to use; pain medication metabolism; identification of alcohol use; determination of patient compliance; and which patient groups to consider for more frequent testing.

Update: Correlation of Fentanyl Positive Drug Screens with other Medications in Patients from Pain, Rehabilitation and Behavioral Programs.

OBJECTIVE: To monitor fentanyl polydrug use over past six years. METHOD: Calculate percent of fentanyl and other drugs positive in urine drug tests. RESULTS: Percent of fentanyl positive drug tests remained unchanged, but increases in fentanyl/methamphetamine and fentanyl/marijuana were observed. CONCLUSIONS: Fentanyl laced illicit drugs remain a major substance abuse problem.

Follow-Up: Effects of a Pandemic and Isolation on Alcohol and Psychoactive Medication Use in a Population of Rehabilitation and Pain Patients.

OBJECTIVE: The conjunction of the coronavirus disease lockdown and the use of illicit drugs suggests the potential increase in drug usage and opioid deaths. Because of other studies, we felt the need to examine if the lockdown has caused a change in the drug intake of our population of substance abuse and pain management patients. Our initial study indicated no increase in the use of illicit and antianxiety drugs. This study is a continuation of that work. MATERIALS: Urine drug testing is a strategy to reduce harm to patients in pain management and substance abuse treatment programs. We analyzed trends in the clinical drug testing patterns of urine specimens sent by substance abuse and pain clinics to monitor their patients. These specimens were tested by a national clinical laboratory using LC-MS/MS definitive methods. The time frame of these comparative observations was the past six years, including the two years of the pandemic. RESULTS: We observed a 30% reduction in test requests during the second quarter of 2020, the number of test requests and specimens submitted was similar during other times of the six-year period. The observed drug use pattern was similar to the earlier study. Among the patients tested, positivity decreased greatly for the illicit drugs heroin and cocaine but increased for methamphetamine and fentanyl. Use of the antidepressant and anxiolytic drugs remained consistent or declined for some drugs, relative to pre-pandemic patterns. The percent of patients prescribed the opiates morphine and oxycodone decreased, while the use of hydrocodone increased. Positivity for the drug gabapentin increased greatly. The use of alcohol did not increase significantly during the lockdown period. CONCLUSION: In summary, these findings demonstrate relatively consistent drug use, with decreased positivity for high-risk drugs and dangerous drug combinations. We speculate that monitoring of these patients mitigates the possibility of drug misuse and potential overdose and is in concordance with the goals of these monitoring programs.

Competitive dopamine receptor antagonists increase the equiactive cocaine concentration during self-administration.

Competitive dopamine receptor antagonists increase the rate of cocaine self-administration. As the rate of self-administration at a particular unit dose is determined by the satiety threshold and the elimination half-life (t(½)) of cocaine, we investigated whether dopamine receptor antagonists altered these parameters in rats. The plasma cocaine concentration at the time of each self-administration was constant during a session demonstrating that this satiety threshold concentration represents an equiactive cocaine concentration. The plasma cocaine concentration at the time of self-administration was increased by SCH23390, consistent with pharmacological theory. In rats trained to reliably self-administer cocaine, SCH23390 had no effect on the plasma steady-state cocaine concentration produced by constant infusions of cocaine. Therefore, this antagonist had no effect on cocaine t(½) at a dose that accelerated cocaine self-administration. A constant cocaine infusion at a rate that maintained steady state concentrations above the satiety threshold stopped self-administration. SCH23390, or the D2 dopamine receptor antagonist (-)eticlopride, reinstated self-administration in the presence of the constant cocaine infusion. This is consistent with SCH23390 and eticlopride raising the satiety threshold above the steady state level produced by the constant cocaine infusion. It is concluded that the antagonist-induced acceleration of cocaine self-administration is the result of a pharmacokinetic/pharmacodynamic interaction whereby the rate of cocaine elimination is faster at the higher concentrations, as dictated by first-order kinetics, so that cocaine levels decline more rapidly to the elevated satiety threshold. This results in the decreased interinjection intervals.

Drugs-of-abuse testing and therapeutic-drug monitoring.

Given the widespread prevalence of drug use and abuse, there is a great need for laboratories to provide identification of prescribed, non-prescribed, and illicit drug use. While the forensics model of drug-abuse testing continues to help provide society protection from criminal behavior, the therapeutic model of drug screening is preferred in the healthcare setting as these laboratories can provide important information to physicians to aid in their diagnosis and help them better protect their patients.

Effects of a Pandemic and Isolation on Alcohol and Psychoactive Medication Use in a Population of Rehabilitation and Pain Patients.

OBJECTIVE: The conjunction of the coronavirus disease lockdown and the use of illicit drugs suggests the potential increase in drug usage and opioid deaths. Because of other studies, we felt the need to examine if the lockdown has caused a change in the drug intake of our population of substance abuse and pain management patients. MATERIALS: Urine drug testing is a strategy to reduce harm to patients in pain management and substance abuse treatment programs. We analyzed trends in the clinical drug testing patterns of urine specimens sent by substance abuse and pain clinics to monitor their patients. These specimens were tested by a national clinical laboratory using LC-MS/MS definitive methods. The time frame of these comparative observations was the past five years, including the time of the pandemic. RESULTS: The only decrease was a 30% reduction in test requests during the second quarter of 2020. Among the patients tested, positivity decreased greatly for the illicit drugs heroin and cocaine but increased for methamphetamine and fentanyl. Use of the antidepressant and anxiolytic drugs remained consistent or declined for some drugs, relative to pre-pandemic patterns. The percent of patients prescribed the opiates morphine and oxycodone decreased, while the use of hydrocodone increased. Positivity for the drug gabapentin increased greatly. The use of alcohol did not increase significantly during the lockdown period. CONCLUSION: In summary, these findings demonstrate relatively consistent drug use, with decreased positivity for high-risk drugs and dangerous drug combinations. We speculate that monitoring of these patients mitigates the possibility of drug misuse and potential overdose and is in concordance with the goals of these monitoring programs.

Correlation of Fentanyl Positive Drug Screens with Other Medications in Patients from Pain, Rehabilitation and Behavioral Programs.

Fentanyl has been associated with many drug overdose deaths; its presence in many street drugs has been postulated to be increasing. We examined 1.3 million urine drug tests from April 2016 to April 2019 for fentanyl and other drugs. The highest relationship was observed with heroin. Approximately 30%-40% of the drug tests positive for the heroin metabolite 6-monacetylmorphine (6-MAM) were also positive for fentanyl. There was a large variance over time, but the percent positive in 2016 and 2019 were similar. In contrast, there was a definite increase in the presence of fentanyl with cocaine and methamphetamine. There was not a large increase over time associated with methadone, buprenorphine, and marijuana.

Reduction of Drug-Drug Interaction Risk; CDC Guidelines Influence on Opiate Benzodiazepine Prescribing.

We examined the results of 1.3 million drug tests performed on patients being monitored for compliance with pain medications and substance abuse rehabilitation to determine if the 2016 CDC prescribing guidelines had any impact on opiate benzodiazepine use. We observed that the combination of the opiate drugs morphine, oxycodone, and hydrocodone with the benzodiazepine metabolites oxazepam, alphahydroxyalprazolam, and 7-aminoclonazepam showed many patients were on a combination of these drugs. This ranged from approximately 9 to 16%. There was considerable variability between opiate drug pairs, but there was a general trend to fewer patients on the combination of opiate-benzodiazepine over the 2016 to 2019 time frame.

6-Acetylmorphine detected in the absence of morphine in pain management patients.

Liquid chromatography tandem mass spectrometry was used to identify and confirm the presence of 6-acetylmorphine and morphine in 22,361 urines of pain management patients. Thirty urines tested positive for 6-acetylmorphine above a cutoff of 10 ng/mL. Twenty-three percent of the patients with urinary concentrations of 6-acetylmorphine above 10 ng/mL had urinary morphine concentrations below 300 ng/mL.

LC-MS/MS extends the range of drug analysis in pain patients.

The current study addresses the distribution of low concentrations of excreted drugs in the pain patient population in an effort to establish a more rational set of cutoffs for this cohort. To wit, 19 analytes in approximately 8000 urine specimens from pain patients were measured using liquid chromatography tandem mass spectroscopy (LC-MS/MS) methodology. The lower limits of quantitation for the LC-MS/MS were set as the nominal cutoffs for the determination of positive and negative results. The measured concentrations were compared with the Substance Abuse & Mental Health Services Administration (SAMHSA) nominal immunoassay cutoffs, and a subset of "missed samples" was identified for each of the 19 analytes. This "missed samples" subset contained all samples that measured above the LC MS/MS cutoff for a given analyte but below the SAMHSA immunoassay cutoff. The number of "missed samples" divided by the total number of samples measured positive by the LC-MS/MS method defines the percentage of this population that would have been found falsely negative if a prescreen by immunoassay using SAMHSA cutoffs had been conducted. For example, 69% of the specimens that were positive for hydromorphone by LC-MS/MS would have been falsely scored as negative by immunoassay.

Anomalous observations of codeine in patients on morphine.

Urine drug monitoring is used by physicians treating chronic pain patients with opioid therapy. Patients are tested in part to insure that they are not taking other drugs. Therefore, the finding of codeine in a patient who is only prescribed morphine has clinical implications. Morphine preparations are known to have small amounts of codeine as an impurity estimated to be about 0.04%. In a population of 535 pain patients prescribed morphine, Kadian, MS Contin, and/or Avinza, the investigators observed 24 samples that contained codeine >20 ng/mL. Fifteen of the 24 contained codeine >20 and <50 ng/mL. Of the 9 samples that were >50 ng/mL, 7 had high levels of codeine (indicating codeine use), 1 was from a patient who had a prescription for codeine, and 1 was also positive for 6-acetylmorphine, indicating heroin use. A control group of 680 patients taking oxycodone was negative for codeine. The finding of codeine was ascribed to the manufacturing process of the morphine medications. Clinicians and laboratories testing urine for drugs should be aware of this possibility.

Unstable propoxyphene metabolite excreted in human urine is detected by liquid chromatography-tandem mass spectrometry.

A "dilute and shoot" method for measuring norpropoxyphene in human urine using liquid chromatography-tandem mass spectrometry distinguishes two different metabolites of propoxyphene, norpropoxyphene (m/z 326) and a dehydrated rearrangement product (m/z 308). The metabolite formed from the rearrangement and dehydration of norpropoxyphene is excreted in human urine and also may be formed from the chemical degradation of norpropoxyphene. Previously, these two metabolites were indistinguishable by gas chromatography- mass spectrometry methods that use an alkaline extraction that converts norpropoxyphene into its rearrangement product. The degradation of norpropoxyphene presents a challenge for its analytical quantitation, and methods for circumventing these issues are presented.