Infrequent detection of unintentional fentanyl use via urinalysis among people who regularly inject opioids in Sydney and Melbourne, Australia.

BACKGROUND AND AIM: The current phase of the North American 'opioid crisis' is characterised by illicit fentanyl use; however, the presence of illicit fentanyl in Australia is unknown. This study aimed to monitor unintentional fentanyl consumption in Australia. DESIGN: Rapid Urine Drug Screens (UDS) paired with surveys conducted within Supervised Injecting Facilities (SIFs), and confirmatory laboratory testing. SETTING: Sydney and Melbourne, Australia PARTICIPANTS: Clients who used heroin within the past 2 days (n=911 tests, 2017-2021). Participants were demographically similar to the overall client base (median age 43, 72% male). MEASUREMENTS: UDS were conducted using BTNX Rapid Response™ fentanyl urine strip tests with cross-reactivity to numerous fentanyl analogues. Positive urine samples were analysed using liquid chromatography coupled with tandem mass spectrometry. Surveys covered past 3 day drug use and lifetime report of fentanyl in heroin. FINDINGS: Two percent of participants reported intentional use of fentanyl, mostly through fentanyl patches. Of the 911 rapid UDS conducted, 17 (1.9%) yielded positive results. Eight of these (all from Melbourne) were not explained by survey-reported fentanyl use in the past 3 days. Of these 8 unexplained positives, confirmatory laboratory analysis was conducted on 6, with 4 deemed to be false positives, and 2 confirmed for the presence of fentanyl. This represents the first confirmation of unintended use of fentanyl type substances in this population. CONCLUSION: There is limited evidence of unintentional fentanyl use among people in Sydney and Melbourne, Australia who regularly inject heroin, suggesting that, currently, there is very little illicit fentanyl in Australian drug markets accessed by Supervised Injecting Facilities attendees. This study demonstrates the feasibility of quick onsite testing to cost-effectively screen large samples for fentanyl; however, the high false positive rate emphasises the need for confirmation of positive tests through advanced analytical techniques

Infrequent detection of unintentional fentanyl use via urinalysis among people who regularly inject opioids in Sydney and Melbourne, Australia.

BACKGROUND AND AIM: The current phase of the North American 'opioid crisis' is characterised by illicit fentanyl use; however, the presence of illicit fentanyl in Australia is unknown. This study aimed to monitor unintentional fentanyl consumption in Australia. DESIGN: Rapid urine drug screens (UDS) paired with surveys conducted within supervised injecting facilities (SIFs) and confirmatory laboratory testing. Setting was Sydney and Melbourne, Australia. PARTICIPANTS: Clients who used heroin within the past 2 days (n = 911 tests, 2017-2021). Participants were demographically similar to the overall client base (median age 43, 72% male). MEASUREMENTS: UDS were conducted using BTNX Rapid Response fentanyl urine strip tests with cross-reactivity to numerous fentanyl analogues. Positive urine samples were analysed using liquid chromatography coupled with tandem mass spectrometry. Surveys covered past 3 day drug use and lifetime report of fentanyl in heroin. FINDINGS: Two percent of participants reported intentional use of fentanyl, mostly through fentanyl patches. Of the 911 rapid UDS conducted, 17 (1.9%) yielded positive results. Eight of these (all from Melbourne) were not explained by survey-reported fentanyl use in the past 3 days. Of these 8 unexplained positives, confirmatory laboratory analysis was conducted on 6, with 4 deemed to be false positives, and 2 confirmed for the presence of fentanyl. This represents the first confirmation of unintended use of fentanyl type substances in this population. CONCLUSION: There is limited evidence of unintentional fentanyl use among people in Sydney and Melbourne, Australia who regularly inject heroin, suggesting that, currently, there is very little illicit fentanyl in Australian drug markets accessed by supervised injecting facilities attendees. This study demonstrates the feasibility of quick onsite testing to cost-effectively screen large samples for fentanyl; however, the high false positive rate emphasises the need for confirmation of positive tests through advanced analytical techniques

Diagnostic accuracy for self-reported methamphetamine use versus oral fluid test as the reference standard in a methamphetamine-dependent intervention trial population

Aims: Treatment of methamphetamine dependence requires monitoring of recent use or abstinence. Self-report is commonly used for routine monitoring, but the accuracy of self-report is not established. For the treating clinician, the key accuracy statistic is the negative predictive value (NPV). The study aim was to estimate the NPV of self-reported non-use of methamphetamine compared with an oral fluid reference standard. Design, Setting and Participants: This study was a secondary (subgroup) analysis from a randomized controlled pharmacotherapy trial. Three Australian outpatient addiction services took part. Particpants were 139 people dependent on methamphetamine. Measurements: Weekly oral fluid samples over 12 weeks to determine methamphetamine (and amphetamine) concentrations were used as the reference standard. Self-report of any methamphetamine use in the previous 7 days by the time-line follow-back method was the index test. Standard diagnostic accuracy statistics were calculated for all available paired episodes (n = 1134). Three NPV values were calculated: unadjusted NPV and NPV adjusted for clustering of observations through logistic regression and generalized estimating equation (GEE). We also calculated the NPVs for a range of prevalence rates of methamphetamine use, for the calculated levels of sensitivity and specificity. Findings: Sensitivity was 96.4% [95% confidence interval (CI) = 95–97.5], specificity was 63.7% (95% CI = 57.3–69.8) and positive predictive value (PPV) was 90.8% (95% CI = 88.8–92.6). The unadjusted NPV was 82.7% (95% CI = 76.5–87.9), adjusted NPV by logistic regression 82.7% (95% CI = 73.9–91.5) and GEE 76.8% (95% CI = 66.8–86.8). At a methamphetamine use prevalence of 5%, the estimated NPV would be 99.7% (95% CI = 99.6–99.9) and at 95% prevalence, 48.2% (95% CI = 39.6–57.0). Conclusions: Self-report of no recent methamphetamine use appears to be sufficiently accurate to be clinically useful at the expected prevalence rates of methamphetamine use in clinical treatment settings. If generalizable to clinical settings, where these tests are routinely conducted, this may permit a reduction in the frequency and cost of oral fluid assays

Promethazine use among chronic pain patients

BACKGROUND: Concomitant use of opioids and promethazine has been reported in various subpopulations, including methadone maintenance patients, injection drug users, and at-risk teenagers. Promethazine is thought to potentiate the “high” from opioids. However, to date, the prevalence of promethazine use has not been determined among patients prescribed opioids for chronic pain. METHODS: Urine samples from 921 patients prescribed opioids for chronic pain were analyzed for promethazine. Demographic data, toxicology results, and opioid prescription information were obtained through medical record abstraction. We assessed the prevalence and factors associated with promethazine use with bivariable and multivariable statistics. RESULTS: The prevalence of promethazine-positive urine samples among chronic pain patients was 9%. Only 50% of promethazine-positive patients had an active prescription for promethazine. Having benzodiazepine-positive urine with no prescription for a benzodiazepine was statistically associated with promethazine use. Also, having a prescription for methadone for pain or being in methadone maintenance for the treatment of opioid dependence were both statistically associated with promethazine use. Chronic pain patients prescribed only a long-acting opioid were more likely to have promethazine-positive urines than patients prescribed a short-acting opioid. CONCLUSIONS: The study provides compelling evidence of significant promethazine use in chronic pain patients. Promethazine should be considered as a potential drug of abuse that could cause increased morbidity in opioid-using populations