An Opioid Hiding in Plain Sight: Loperamide-Induced False-Positive Fentanyl and Buprenorphine Immunoassay Results.

BACKGROUND: Loperamide (Imodium®), a commonly used anti-diarrheal, is a mu opioid receptor agonist that, like all opioids, reduces gastrointestinal tract peristalsis. Loperamide is considered to have low abuse potential as it does not produce an analgesic or euphoric effect due to low bioavailability and first-pass metabolism. However, reports of individuals misusing loperamide through the use of super-therapeutic doses, alone or in combination with P-glycoprotein and/or CYP450 enzyme inhibitors, is increasing. We hypothesized that loperamide could potentially cross-react with laboratory immunoassay drug screens. METHODS: Drug-free urine was spiked with loperamide or its principal metabolite, N-desmethyl loperamide (dLop), and assayed on multiple fentanyl and buprenorphine assays. Fentanyl immunoassay screen-positive results at one institution were examined by high-resolution mass spectrometry (MS) for the presence of loperamide and quantified by liquid chromatography- tandem MS when positive. RESULTS: Loperamide produced positive results on the Thermo DRI Fentanyl and Immunalysis Fentanyl assays at concentrations greater than 5.72 mg/L and 23.7 mg/L. dLop generated positive results for the Thermo DRI and Immunalysis fentanyl assays at concentrations exceeding 6.9 mg/L and 35.7 mg/L. dLop also produced positive buprenorphine results on the Thermo CEDIA buprenorphine assay at concentrations exceeding 12.2 mg/L. High-resolution MS analysis of 225 fentanyl immunoassay positives (Thermo DRI) yielded 5 specimens containing loperamide and/or dLop, 4 of which contained measurable quantities of fentanyl in addition to loperamide/dLop. CONCLUSIONS: Laboratories using these assays should be aware of the potential for false-positive screening results due to the presence of high concentrations of loperamide and its metabolite dLop.

Investigation of buprenorphine-related deaths using urinary metabolite concentrations.

Quantitative analysis of postmortem urine, instead of blood, for buprenorphine and metabolites may provide additional evidence for the diagnosis of fatal buprenorphine poisoning. In this study, 247 autopsy urine samples, previously testing positive for buprenorphine or norbuprenorphine, were quantitatively reanalysed with a recently developed liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for unconjugated buprenorphine (BUP), norbuprenorphine (NBUP), naloxone (NAL), and their respective conjugated metabolites, buprenorphine glucuronide (BUPG), norbuprenorphine glucuronide (NBUPG), and naloxone glucuronide (NALG). The cases were divided, according to medical examiners' decision, to buprenorphine poisonings and other causes of death. The groups were compared for urinary concentrations and metabolite concentration ratios of the six analytes. All median concentrations were higher in the buprenorphine poisoning group. The median concentration of BUPG was significantly higher and the median metabolite ratios NBUP/BUP, NBUPG/BUPG, and NBUPtotal/BUPtotal were significantly lower in poisonings than in other causes of death. Naloxone-related concentrations and ratios were not significantly different between the groups.

Norbuprenorphine Interferences in Urine Drug Testing LC-MS-MS Confirmation Methods from Quetiapine Metabolites.

Norbuprenorphine interferences were observed in urine drug testing LC-MS-MS confirmation methods used to assess patient compliance with prescribed buprenorphine for chronic pain and opioid use disorder. The interferences were observed in the norbuprenorphine MS-MS transitions, m/z 414.4/83.1 and 414.4/187.2, at and near the norbuprenorphine retention time at multiple laboratories using different sample preparation procedures and chromatographic conditions. When the interferences were present, a norbuprenorphine result could not be reported. Upon investigation, the interferences were correlated with prescribed quetiapine (Seroquel, Seroquel XR), a second-generation antipsychotic medication approved for the treatment of schizophrenia, bipolar disorder and more recently as an adjunct treatment for major depressive disorder. In addition to the approved indications, quetiapine is prescribed off-label for other conditions including insomnia and anxiety disorders. Off-label prescribing has increased in recent years, thereby exacerbating this analytical issue. Here, we present the study of four quetiapine metabolites found to have significant direct or potential interferences in norbuprenorphine quantitation. The four metabolites were putatively identified as two hydroxyquetiapine acids differing in the site of hydroxylation and a quetiapine sulfoxide acid diastereomer pair. As a result of this study, interference-free norbuprenorphine MS-MS transitions, m/z 414.4/340.2 and 414.4/326.1, were found that were selective for norbuprenorphine while maintaining an acceptable 10 ng/mL lower limit of quantitation.

Determination of buprenorphine, norbuprenorphine, naloxone, and their glucuronides in urine by liquid chromatography-tandem mass spectrometry.

A liquid chromatography-tandem mass spectrometry method for the simultaneous quantification of buprenorphine (BUP), norbuprenorphine (NBUP), naloxone (NAL), and their glucuronide conjugates BUP-G, NBUP-G, and NAL-G in urine samples was developed. The method, omitting a hydrolysis step, involved non-polar solid-phase extraction, liquid chromatography on a C18 column, electrospray positive ionization, and mass analysis by multiple reaction monitoring. Quantification was based on the corresponding deuterium-labelled internal standards for each of the six analytes. The limit of quantification was 0.5 µg/L for BUP and NAL, 1 µg/L for NAL-G, and 3 µg/L for NBUP, BUP-G, and NBUP-G. Using the developed method, 72 urine samples from buprenorphine-dependent patients were analysed to cover the concentration ranges encountered in a clinical setting. The median (maximum) concentration was 4.2 µg/L (102 µg/L) for BUP, 74.7 µg/L (580 µg/L) for NBUP, 0.9 µg/L (85.5 µg/L) for NAL, 159.5 µg/L (1370 µg/L) for BUP-G, 307.5 µg/L (1970 µg/L) for NBUP-G, and 79.6 µg/L (2310 µg/L) for NAL-G.

Trends in Urine Drug Monitoring Among Persons Receiving Long-Term Opioids and Persons with Opioid Use Disorder in the United States.

BACKGROUND: Practice guidelines recommend urine drug monitoring (UDM) at least annually in the setting of chronic opioid therapy as an objective assessment of substance use. However, empirical evidence on who gets tested and how often testing occurs is lacking. OBJECTIVES: This study investigates 10-year UDM trends in the United States based on 2 factors: (1) the duration of prescription opioid treatment, and (2) having an opioid use disorder (OUD) diagnosis and medications for opioid use disorder (MOUD) prescriptions. STUDY DESIGN: Observational cross-sectional study. SETTING: Research was conducted using administrative claims data from Optum's deidentified Clinformatics Data Mart Database for the period 2007 to 2016. The dataset contained information on the plan enrollment and health care claims from 50 states and the District of Columbia. METHODS: To examine trends in UDM based on the duration of prescription opioid treatment, persons receiving prescription opioid analgesics were categorized into 4 groups based on the number of days covered: (a) less than 90 days, (b) 90 to 179 days, (c) 180 to 269 days, and (d) at least 270 days. To examine trends based on an OUD diagnosis and MOUD prescriptions, persons diagnosed with OUD were identified and categorized based on the presence of MOUD prescriptions as follows: (a) OUD with buprenorphine (BPN) and naltrexone (NTX) in the same year; (b) OUD with BPN only; (c) OUD with NTX only; (d) OUD with chronic prescription opioid analgesics (>= 90 days); (e) OUD without prescription opioid analgesics, BPN, or NTX; and (f) chronic prescription opioid analgesics (>= 90 days) without an OUD diagnosis. For analysis, the percent receiving UDM was estimated per group per year. Then the data were restricted to those receiving at least one UDM to estimate the average number of UDM per person. RESULTS: Data included an average of 364,485 persons per year receiving prescription opioid analgesics for chronic use, and 10,277 per year receiving an OUD diagnosis. Among those receiving prescription opioid analgesics, less than 50% received UDM. For those receiving at least one UDM, one additional UDM was performed per person as the duration of opioids increased by 90 days. Among persons with OUD, the percent receiving UDM was the highest for those receiving both BPN and NTX (87%), followed by those receiving BPN only (80%), chronic opioids (79%), NTX only (72%), and those not receiving any MOUD/opioids (54%). LIMITATIONS: Methadone dispensing for OUD treatments was not captured in administrative claims data. CONCLUSIONS: Although recommended for patients with chronic pain, UDM is provided less than half of the time for these patients. However, once patients received at least one UDM, they would continue to receive it on a fairly regular basis. Compared with those with chronic pain, persons diagnosed with OUD are more likely to receive UDM at a more frequent interval.

Are point-of-care urine drug testing devices suitable for antenatal drug screening? A study verifying the Alere® Drug Screen Test Cup for the detection of six classes of drug in a pregnant population.

BACKGROUND: Currently, there are no national guidelines for antenatal drug testing. At Colchester Hospital, we use a strategy of screen-only using point-of-care testing to detect illicit drug use in pregnancy. To determine the suitability of this approach, we have compared the results of urine analysis by point-of-care testing with another NHS specialist clinical toxicology service that uses confirmation mass spectrometry. METHODS: A total of 482 anonymized random urine specimens from antenatal clinics were tested for six drug classes: amphetamine, benzodiazepines, buprenorphine, cocaine, methadone and opiates using the Alere™ Drug Screen Urine Test Cup. The manufacturer's claims for positive cut-off and result stability were verified using spiked blank urine. Confirmatory testing was performed using ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) for detection of 26 individual drugs. RESULTS: Of 473 urine samples with adequate volume for point-of-care screening, 4.4% tested positive: 19 opiate and 2 cocaine. Concordance between point-of-care screening and UPLC-MS/MS confirmation was 97.9% for all drugs and 78.9% for opiates. Using spiked urine, only positive results for opiates were stable when read up to the manufacturer's recommended time of 60 min. CONCLUSIONS: The key advantages of using point-of-care devices to detect drug use in pregnancy are that is convenient and cheap. However, the clinical utility of point-of-care testing is limited by its poor sensitivity. Best practice is to confirm results using a more specific and sensitive method. As a result of this study, we are now reviewing our own procedures to consider introducing routine confirmation by mass spectrometry.

Dispersive solid-phase extraction of buprenorphine from biological fluids using metal-organic frameworks and its determination by ultra-performance liquid chromatography.

In this work, various types of metal-organic frameworks were synthesized, and their affinities toward buprenorphine were evaluated using dispersive solid-phase extraction. The extracted buprenorphine was determined by ultra high performance liquid chromatography-ultraviolet detection system. The highest extraction recovery was observed by employing zeolitic imidazole framework-67. Then, a facile and fast extraction method was designed for the extraction and purification of the target drug. Optimization of the extraction method was carried out by the design of experiment approach. A linearity range of 1-1000 µg/L with the limit of detection of 0.15 µg/L and relative standard deviations (50 µg/L, n = 5) of 3.4% was obtained for standard sample analysis. Under optimized experimental and instrumental conditions, the relative recoveries were in the range of 95 to 111%. Eventually, zeolitic imidazole framework-67 was successfully employed for the extraction and determination of buprenorphine in the biological fluids with satisfactory results.

High Prevalence of Buprenorphine in Prenatal Drug Screens in an Appalachian City.

OBJECTIVES: To define the magnitude of buprenorphine presence in the urine drug screens of pregnant women and to assess the presence of illicit buprenorphine use versus the presence of prescribed buprenorphine use. METHODS: Initial prenatal drug screen results for all pregnant patients in our practice for a 1-year period were analyzed and tabulated. RESULTS: Buprenorphine was found in the urine drug screens of 16% of pregnant patients. The presence of buprenorphine was by far the highest for any substance associated with neonatal abstinence syndrome (NAS). We estimate that the exposure to buprenorphine of approximately one-third of individuals in our population is associated with illicit buprenorphine use. CONCLUSIONS: The high rate of NAS in our region is primarily associated with both illicit and prescribed buprenorphine rather than other substances. Buprenorphine usage at the time that prenatal care is initiated, rather than opiate use at the onset of prenatal care, is the underlying factor that must be addressed if our region is to successfully combat our high rates of NAS.

Buprenorphine Treatment for Opioid Use Disorder in Community-Based Settings: Outcome Related to Intensity of Services and Urine Drug Test Results.

BACKGROUND AND OBJECTIVES: Variables contributing to the outcome of buprenorphine treatment for opiate use disorder have been studied, including patient characteristics and the treatment approach applied. It is also valuable to study the types of clinical facilities that can affect outcome. METHODS: We evaluated patients (N = 20 993) in 573 facilities where buprenorphine was prescribed. Urine drug test results were analyzed for those (N = 13 281) who had buprenorphine prescribed at least twice in the period January 2015 through June 2017. Facilities were divided into three categories: medication management (MM) only, limited psychosocial (LP) therapy, and recovery-oriented (with more extensive counseling and a 12-step orientation) (RO). RESULTS: Urine drug tests negative for other opioids at the time of the second buprenorphine prescription were 34% for MM, 56% for LP, and 62% for RO (P < .001). A comparison was made between the most recent and the established patients at the facilities. The decrement in urinalyses positive for other opioids in this latter comparison was 3% for MM, 7% for LP, and 23% for RO (P < .001). DISCUSSION AND CONCLUSIONS: In a large sample of community settings, buprenorphine patients' urinalyses positive for opioids can vary considerably across treatment facilities, and more intensive recovery orientation may yield a better outcome in terms of secondary opioid use. SCIENTIFIC SIGNIFICANCE: The majority of buprenorphine patients are treated in community facilities. It is important that research be done by facility type in such settings in order to plan for optimal treatment. (© 2020 The Authors. The American Journal on Addictions published by Wiley Periodicals, Inc.;00:00-00).

Use of urinary naloxone levels in a single provider practice: a case study.

BACKGROUND: Urine drug monitoring for medications for opioid use disorder (MOUD) such as buprenorphine can help to support treatment adherence. The practice of introducing unconsumed medication directly into urine (known as "spiking" samples) has been increasingly recognized as a potential means to simulate treatment adherence. In the laboratory, examination of the ratios of buprenorphine and its metabolite, norbuprenorphine, has been identified as a mechanism to identify "spiked" samples. Urine levels of naloxone may also be a novel marker in cases where the combination buprenorphine-naloxone product has been administered. This case study, which encompasses one provider's practice spanning two sites, represents a preliminary report on the utility of using urinary naloxone as an indicator of "spiked" urine toxicology samples. Though only a case study, this represents the largest published evaluation of patients' naloxone levels to date. CASE PRESENTATION: Over a 3-month period across two practice sites, we identified 1,223 patient samples with recorded naloxone levels, spanning a range of 0 to 12,161 ng/ml. The average naloxone level was 633.65 ng/ml with the majority (54%) of samples < 300 ng/ml. 8.0% of samples demonstrated extreme values of naloxone (> 2000 ng/ml). One practice site, which had increased evidence of specimen tampering at collections, had a greater percent of extreme naloxone levels (>  2000 ng/ml) at 9.3% and higher average naloxone level (686.8 ng/ml), in contrast to a second site (570.9 ng/ml; 6.4% at > 2000 ng/ml) that did not have known reports of specimen tampering. CONCLUSIONS: We postulate that naloxone may serve as an additional flag to identify patient "spiking" of urine samples with use of the combination product of buprenorphine-naloxone.

Drug screening during pregnancy: Urine dip cups measure up.

BACKGROUND: Substance use during pregnancy is a major medical and public health concern. Determination of the most appropriate screening protocol remains a clinical conundrum. Interviews and/or laboratory drug screens may be costly, inaccurate, and are frequently inadequate to identify patterns of substance use for a given population or geographic area. We compared commercially available urine "dip cup" toxicology screens obtained in the clinic to university hospital drug toxicology results. METHODS: 267 observed urine samples were collected from pregnant women with known substance use disorders enrolled in a specialized treatment program that included access to buprenorphine medication-assisted treatment. Each urine sample was tested by commercial dip cup with temperature confirmation and then sent to the university hospital laboratory for analyses. The number of substances detected and cost for each screening method were compared. RESULTS: Uniformly, the dip cup had comparable detection of amphetamines, barbiturates, cocaine, methadone, opiates, and tetrahydrocannabinol to the university hospital laboratory with the exception of benzodiazepines. In addition, the dip cup detected use of buprenorphine (a commonly misused opiate receptor ligand not included in the hospital screen) and was significantly less expensive. CONCLUSIONS: Commercially available urine dip cups are cost-effective, equally comparable to hospital based screening, and provide 'real time' results germane to clinical care and treatment planning.

Highly selective extraction and voltammetric determination of the opioid drug buprenorphine via a carbon paste electrode impregnated with nano-sized molecularly imprinted polymer.

An electrochemical sensor for the opioid drug buprenorphine (BUP) is described. Molecularly imprinted polymer nanoparticles (nanoMIP) were prepared and used to modify a carbon paste electrode (CPE). The BUP-imprinted polymer was synthesized using precipitation polymerization. The resulting polymer along with multiwalled carbon nanotubes (MWCNT) was used to fabricate the modified CPE which exhibited an anodic peak at about +0.73 V (vs. Ag/AgCl) for BUP. The MIP on the CPE functions as selective recognition element with an imprinting factor of 5.6. The assay consists of two-steps, viz. analyte extraction at the electrode surface and differential pulse voltammetric determination of BUP. The effects of various parameters on the electrochemical signal were optimized, and the selectivity of the modified CPE over cross reactants was studied. At optimum experimental conditions, the response is linear in the 1 nM to 50 µM BUP concentration range, and the detection limit is 0.6 nM (at S/N = 3). This method was applied to the determination of BUP in spiked urine with acceptable relative standard deviations (3.2-4.4%). Graphical abstract Schematic representation of buprenorphine (BUP) recognition and voltammetric determination at the surface of carbon paste electrode modified with imprinted polymer and carbon nanotubes.

Urine is superior to oral fluid for detecting buprenorphine compliance in patients undergoing treatment for opioid addiction.

BACKGROUND: Buprenorphine (BUP) is commonly used in opioid agonist medication-assisted treatment (OA-MAT). Oral fluid (OF) is an attractive option for compliance monitoring during OA-MAT as collections are observed and evidence suggests that OF is less likely to be adulterated than urine (UR). However, the clinical and analytical performance of each matrix for monitoring BUP compliance has not been well studied. METHODS: We collected 260 paired OF and UR specimens. Concentrations of buprenorphine (BUP) and norbuprenorphine (NBUP) were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in each matrix. The glucuronide metabolites and naloxone concentrations were also measured in UR by LC-MS/MS. Medications were reviewed and UR creatinine concentrations were determined. RESULTS: 147/260 specimens (57%) were positive for BUP and/or metabolites in one or both matrices. BUP and/or metabolites were more likely to be detected in UR (p < 0.001). 1 OF specimen and 12 UR specimens were considered adulterated/substituted. The majority of patients prescribed BUP were positive for BUP in UR (97%) as opposed to OF (78%). The detection of undisclosed use approximately doubled in UR. CONCLUSIONS: UR is the preferred matrix for detecting both buprenorphine compliance and undisclosed use. Clinicians should consider the ease of collection, risk of adulteration and detection of illicit drug use when deciding on an appropriate matrix. If OF testing is clinically necessary, UR should be measured in conjunction with OF at least periodically to avoid false negative BUP results.

Enzymatic assay for urine lactose in the assessment of recent intravenous abuse of buprenorphine.

Urine samples were analyzed for lactose to investigate if elevated lactose concentrations indicate recent (< 48 hours) intravenous abuse of substances containing lactose as an excipient. Elevated lactose levels were found in samples given by patients who had recently injected substances intravenously, verified by fresh injection marks. Urine lactose assay can support clinical and toxicological findings when assessing substance abuse.

A Novel Enzyme Immunoassay for the Detection of Buprenorphine, Norbuprenorphine and Their Glucuronides in Urine.

Buprenorphine is a commonly used opioid in pain therapy as well as in opiate maintenance therapy. Immunoassays are quick and cost-effective methods for the necessary toxicological urine analysis of maintenance therapy patients. In this study a novel enzymatic immunoassay, the Thermo Fisher Scientific CEDIA Buprenorphine II assay (Bup2) was evaluated for the detection of buprenorphine, norbuprenorphine and their conjugated metabolites in human urine samples. The Bup2 assay has a cut-off of 10 ng/mL with ±25% controls, whereas the existing CEDIA Buprenorphine assay (Bup1) has a cut-off of 5 ng/mL and ±40% controls. Both assays were analyzed on a Thermo Scientific Indiko Plus benchtop analyzer. Seven-day precision studies of Bup2 assay demonstrated excellent precision of 7.2-10.6%. No crossover between control samples and the cut-off level were observed. Urine samples of 120 patients undergoing opiate maintenance therapy were collected. Immunoassay results of Bup1 and Bup2 were confirmed by gas chromatography mass spectrometry (GC/MS) for buprenorphine and norbuprenorphine as well as for their glucuronides. Comparison showed a specificity of 0.99 between the Bup2 assay and GC/MS, whereas the Bup1 assay had a specificity 0.70 due to 21 false positive samples. The reason is a known cross-reactivity of the Bup1 assay to opiate compounds. The Bup2 assay revealed one false positive result close to the cut-off value; no specific candidate possibly causing a cross-reaction was detected by GC/MS and liquid chromatography tandem mass-spectrometry (LC/MS/MS) methods. The data presented demonstrate an excellent correlation of the Bup2 assay to GC/MS, showing improved specificity and sensitivity when compared to the Bup1 assay. Thus, the Bup2 assay is highly suitable for urine testing, even for opiate maintenance patients receiving high doses of morphine.

Rapid, hydrolysis-free, dilute-and-shoot method for the determination of buprenorphine, norbuprenorphine and their glucuronides in urine samples using UHPLC-MS/MS.

Buprenorphine and its metabolites are routinely monitored to assess patient compliance with drug detoxification programs or as pain killers. A rapid method for the simultaneous analysis of buprenorphine, norbuprenorphine, and glucuronides in urine using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was developed. Urine samples were diluted in water containing formic acid 0.1% and directly injected into the UHPLC-MS/MS system without any sample pretreatment. Quality control (QC) samples, prepared using 20 different urine matrices, fortified at 3 concentration levels, were quantified using four deuterated internal standards. The accuracy values obtained spanned from 90 to 114% with repeatability lower than 10% also in the inter-day between batch experiments. Matrix effects (ME), evaluated before correction with internal standards using Matuszewski procedure, mainly affected the analysis of buprenorphine glucuronide. The use of deuterated internal standards (IS) for each analyte was necessary to compensate for ME and was essential in the determination of glucuronides. The method was applied to 30 real urine samples from patients under a detoxification therapy. Duplicate analyses were performed with the presented method and compared with another method which involves a standard hydrolysis procedure. Real sample results were compared showing a good performance agreement, with differences between the two methods lower than ±20% in the quantification results.

Measurement of Buprenorphine and Norbuprenorphine in Urine.

Buprenorphine, a synthetic opioid possessing both analgesic and opioid receptor antagonist properties, has proven to be an effective therapeutic aid for opioid dependency and chronic pain management. The downside, as with all opioids, natural or synthetic, is its potential for misuse and abuse. The euphoria induced by buprenorphine leads to abuse. Additionally, individuals with an active addiction to short-acting opioids such as heroin may use buprenorphine between doses of their drug of choice to stave off withdrawal symptoms. As such, buprenorphine monitoring is utilized in medication-assisted therapy programs for opioid dependency, as well as chronic pain management settings. Buprenorphine may also be included in drug testing programs for law enforcement purposes. The assay described here was designed to detect and quantify both buprenorphine and its metabolite norbuprenorphine.