Blood Fentanyl Research Articles

Case report of pharmacokinetic analysis of continuous intravenous infusion of fentanyl in a patient with severe burn: burn shock stage complicates pain management

BackgroundFentanyl is widely used as an analgesic and sedative for patients with severe burn injuries in intensive care units. However, pharmacokinetic (PK) data for fentanyl, particularly for continuous intravenous infusion during the acute phase of burn injuries, are limited. Here, we report the clinical course and changes in blood fentanyl concentrations during the acute phase in a patient with severe burns treated with continuous intravenous infusion of fentanyl.Case presentationA woman in her 40s, with burns caused by a gas cylinder explosion, was transported to our hospital. The patient had burn wounds on face, neck, shoulders, and all four extremities, with a total burn area of 39.0%. For pain relief, the patient received a continuous infusion of 0.01 mg/mL fentanyl (20–30 µg/h) with a target blood concentration of 1.0–1.5 ng/mL, but continued to suffer from pain due to burning during the acute phase. We measured the blood fentanyl concentrations and found that all concentrations obtained during the acute phase were subtherapeutic. Notably, during the burn shock stage, blood concentrations of fentanyl were 0.50 ng/mL on day 1 and 0.66 ng/mL on day 2, indicating that the blood concentration did not rise sufficiently for the dosage. From days 0 to 2, the patient was administered a massive fluid load for burn shock. After the burn shock stage resolved, fentanyl concentrations gradually approached the target range, and the pain rating scale improved, even though the fentanyl administration rate remained unchanged (30 µg/h).ConclusionsMajor changes in the fluid volumes of body compartments that occur with large burns might increase the volume of fentanyl distribution, thereby lowering its concentration when a standard dose is administered. Our findings indicate that the PK of fentanyl in patients with severe burns can be substantially affected, especially during the shock phase, implying the importance of titrating analgesics for clinical efficacy in the acute phase.

A quantitative LC-MS/MS analysis of Xylazine, p-Fluorofentanyl, Fentanyl and Fentanyl-Related compounds in postmortem blood

The purpose of this study was to develop and validate a method to quantitate the veterinary sedative xylazine as well as 4-anilino-N-phenethylpiperidine (4-ANPP), acetyl fentanyl, fentanyl, norfentanyl, and p-fluorofentanyl in blood utilizing liquid chromatography tandem mass spectrometry. This method also qualitatively monitors for the presence of o-fluorofentanyl and m-fluorofentanyl isomers. UCT Clean Screen® DAU extraction columns were utilized to isolate the analytes in postmortem blood samples. The extracts were eluted, evaporated, reconstituted, and then analyzed using a Waters Acquity™ UPLC coupled a triple quadrupole mass spectrometer. The lower limit of quantitation was determined to be 0.1 ng/mL for all analytes, except for xylazine (0.2 ng/mL). The upper limit of quantitation for all analytes was 100 ng/mL. No interferences from matrix, internal standard, or common drug analytes were observed. Bias (-13.1–4.6 %) and precision (-13.14–10.3 %) fell within the acceptable ± 20 % criteria range. Dilution integrity at x2, x10, and x100 was evaluated and all results were within ± 20 % of the target concentration. Processed extract stability was evaluated after 72 h and all results were within ± 20 % of the analyte initial concentration. Matrix effects were the most prominent with xylazine, but deemed acceptable as the deuterated internal standard also observed comparable enhancement. Analysis of 89 postmortem blood samples by this method resulted in positive results for fentanyl (0.27–66 ng/mL, n = 82), xylazine (0.24–958 ng/mL, n = 21), 4-ANPP (0.10–38 ng/mL, n = 72), acetyl fentanyl (0.18–1.5 ng/mL, n = 3), p-fluorofentanyl (0.11–33 ng/mL, n = 30), and norfentanyl (0.10–98 ng/mL, n = 73).

A Series of 8 Illicit Fentanyl Intoxication Deaths in Infants and Toddlers.

We report 8 children younger than 2 years who died from acute illicit fentanyl intoxications in Connecticut between 2020 and 2022.The Connecticut Office of the Chief Medical Examiner (CT OCME) investigates all unexpected, violent, and suspicious deaths in Connecticut. The CT OCME's electronic database was searched for fentanyl deaths by age. All underwent autopsies and toxicology testing.The ages ranged from 28 days to 2 years (mean age, 12 months). The causes of death involved acute fentanyl intoxications with 1 having xylazine, 1 having para-fluorofentanyl, and 1 having cocaine and morphine. All the manners of death were certified as homicide. The postmortem fentanyl blood concentrations ranged from 0.40 to 46 ng/mL. Most of the children were found unresponsive after being put to sleep. Three were co-sleeping with adults (2 in bed; 1 on a recliner). There was a known history of parental/caregiver drug abuse in 7 of 8 of the fatalities.We summarize the key investigative, autopsy, and toxicological findings. As illicit fentanyl use increases, there is a potential for infant exposure and death. The investigation and certification of these deaths and the role of intentional administration versus inadvertent exposure due to caregiver neglect in the context of the certification of the manner of death are described.

Evaluation of the relationship of xylazine and fentanyl blood concentrations among fentanyl-associated fatalities

Introduction Illicit fentanyl and fentanyl-analogs have produced a devastating increase in opioid fatalities in the United States. Increasingly, xylazine has been found in the illicit fentanyl supply. The role of xylazine in fentanyl intoxication remains unclear. We reviewed coroner records to evaluate trends and effects associated with xylazine in fentanyl-related fatalities. Methods This is a retrospective cohort study of all deaths reported to the Franklin County Coroner’s Office in Ohio from 1 January 2019 to 16 March 2023, in which fentanyl was determined causative or contributory to death. Cases identified as fentanyl-associated fatalities were separated into two groups based on whether or not xylazine was also detected. Results There were 3,052 fentanyl-related fatalities during the study period. 4.8 percent of these decedents also tested positive for xylazine. There was no meaningful demographic difference between fentanyl-related fatalities in which xylazine was detected versus those without xylazine detected. There was a mean of 726 fentanyl-associated fatalities per year, with a peak of 846 deaths in 2020 and a decline thereafter. The percentage of fentanyl-related fatalities with xylazine detected increased in linear fashion from 2.7 percent in 2019 to 6.6 percent in 2022. The median fentanyl concentration was 17.0 µg/L (inter-quartile range: 7.9, 27.0) in cases with xylazine detected and 10.0 µg/L (inter-quartile range: 5.6, 18.0) without xylazine. The odds of a fentanyl concentration greater than 40 µg/L in cases with xylazine detected was more than twice as great (odds ratio: 2.41; 95 percent confidence interval: 1.58–3.64) than that in cases without xylazine detected. Conclusions Postmortem fentanyl concentrations were greater in cases with xylazine detected than those without xylazine detected. Though it is unclear why patients who were exposed to xylazine tolerated higher opioid doses prior to succumbing to death, we postulate that xylazine may act to competitively antagonize some degree of mu-opioid receptor binding by opioids.

Developing mathematical models to compare and analyse the pharmacokinetics of morphine and fentanyl.

The two-compartment model is generally used in pharmacokinetics to illustrate the distribution and excretion of drugs. In this study, we evaluated the distribution patterns of morphine and fentanyl by using a two-compartment model. Using numeric analysis techniques, non-linear ordinary differential equations were used to mathematically analyse drug distribution, transition, and concentration in the body compartments. Math Works, Inc., MATLAB, version 2023a, a programming tool, was used to characterise the impact of initial concentration and rate constants on the kinetics of the drug. For a definite therapeutic concentration of morphine and fentanyl in blood, pharmacokinetic characteristics were plotted. The study results showed the time taken by morphine and fentanyl to reach a target concentration in the blood that is sufficient to generate the preferred therapeutic effects. The mathematical models comparing morphine and fentanyl pharmacokinetics showed that fentanyl reached the target therapeutic concentration 125 minutes earlier than morphine and was metabolised and removed from the body more rapidly (44 minutes earlier than morphine). These comparative mathematical models on morphine and fentanyl enable the determination of drug dosages and understanding of drug efficacy that facilitates optimising dosing regimens. The right choice between them can be made based on the time to reach the target therapeutic concentration in the blood, elimination time, severity of pain, and patient characteristics.

Quantifying a potential protective effect of buprenorphine on fatality risk during acute fentanyl exposures

IntroductionBuprenorphine is an important therapy for opioid use disorder and may also reduce the risk of fatal overdoses in fentanyl exposures. However, the role of buprenorphine in reducing this risk has not been quantified. This cross-sectional study examined the association between buprenorphine presence, decedent characteristics, and other factors with the predicted fentanyl concentrations in overdose deaths. MethodsThe study identified unintentional fentanyl overdose decedents (n = 3036) from the West Virginia Forensic Drug Database, 2011 through mid-2020. The main outcome was fentanyl concentrations in overdose deaths in the presence and absence of buprenorphine. A multiple linear regression model examined the association of fentanyl concentrations with buprenorphine presence based on the concentrations of the parent drug buprenorphine (B) and its metabolite norbuprenorphine (N), adjusting for demographics, toxicological characteristics (presence of multiple opioids, benzodiazepines, stimulants, marijuana, and alcohol), and comorbidities. We used a B/N concentration ratio < 1 as an indirect indicator of longer-term buprenorphine exposure prior to drug overdose death. ResultsThe median fentanyl concentration was 65 % higher when buprenorphine was present (N = 168) vs. absent (N = 2868) (0.028 vs. 0.017 μg/mL, p < 0.001). In the multivariable model, statistically significant associations occurred between buprenorphine presence and increased fentanyl concentrations (+28.7 %) with a B/N ratio < 1. Obesity, male sex, alcohol presence, and comorbid cardiovascular diseases were statistically significantly associated with lower (−11.3 % to −20.7 %) fentanyl concentrations, whereas marijuana presence and a history of substance use disorder were associated with statistically significant higher fentanyl concentrations (+8.8 % to +31.3 %). ConclusionsThese findings suggest that sustained or longer-term buprenorphine intake might exert some protective effect on fatalities resulting from fentanyl exposure as documented by the association of higher fentanyl blood concentrations with buprenorphine presence among fatal drug overdoses. As fentanyl availability and overdose rates increase nationally, buprenorphine is a vital tool for effective opioid use disorder treatment that might also reduce the risk of fatality in an acute fentanyl exposure.

Quantification of Fentanyl and Norfentanyl in Whole Blood Using Liquid Chromatography-Tandem Mass Spectrometry.

Fentanyl is a synthetic opioid used in pain management with a potency 50-100 times that of morphine. Due to fentanyl's high potency, very low dosages are needed to elicit the desired response. Fentanyl is gaining popularity as a drug of abuse. Overdose of fentanyl causes respiratory depression that can lead to death. Fentanyl undergoes N-dealkylation in the liver to its inactive metabolite norfentanyl. Quantitation of fentanyl and its metabolite norfentanyl in whole blood can be performed using liquid chromatography-mass spectrometry. In this method, whole blood samples are spiked with deuterated internal standards for fentanyl and norfentanyl. The samples are alkalized with potassium hydroxide and the drugs are extracted with an organic solvent. Extracts are dried and reconstituted, then injected on LC-MS/MS. They are quantitated using positive ion multiple reaction monitoring (MRM) mode.

The rise and rise of fentanyl in postmortem casework.

Forensic toxicology laboratories are navigating a period of time with increasing drug overdose deaths, an opioid epidemic, the impact of the COVID-19 pandemic, and the illicit drug market flooded with novel psychoactive substances. In New York City, the Department of Forensic Toxicology has experienced a 56% increase in postmortem casework in the past decade with fentanyl detected in 80% of all overdose deaths. Over a period of 2.5 years, 15,638 postmortem cases were tested for the presence of fentanyl and fentanyl analogs using liquid-chromatography tandem mass spectrometry (LCMSMS). Fentanyl was detected in approximately one third of cases and of these 4447 cases with femoral blood. A twofold increase in cases with high concentrations of fentanyl (>100 ng/mL) was observed between 2021 and 2022. The minor metabolite and precursor chemical, 4-ANPP (4-anilino-N-phenethylpiperidine) may help differentiate between illicit and licit fentanyl. 4-ANPP blood concentrations were <10 ng/mL in 98% of the cases and the 4-ANPP:fentanyl ratio was <0.67 for 99.1% of blood specimens. Only six cases had 4-ANPP concentrations higher than the corresponding fentanyl blood concentration. This study also highlights, the changing fentanyl analogs found in postmortem cases since 2016 in NYC with the emergence of fluorofentanyl initially identified in 2020 and continuing to dominate in comparison with the prevalence of other analogs, many of which are no longer detected in casework. The detection of one of the latest drugs to be mixed with fentanyl, namely xylazine, has also increased in prevalence by 36.7% in 2022 compared with 2021.

Fentanyl concentrations in ligated femoral blood in the presence and absence of NPS benzodiazepine drugs. A review of over 1250 benzo-dope / fentanyl toxicity cases in Alberta, Canada

The drug combination referred to as ‘benzo dope’ has become prevalent in recent years, with an increasing number of fentanyl-related deaths reporting the concomitant presence of one or more benzodiazepine drug, such as etizolam, flualprazolam and flubromazepam. The central nervous system (CNS) depressant effects of these benzodiazepine drugs can exacerbate respiratory and CNS depressant effects resulting from the use/misuse of potent opioids such as fentanyl. This combined and enhanced drug-induced toxicity can pose a significant threat to life. Over a three-year period (2020–2022), the Office of the Chief Medical Examiner, Edmonton, Alberta, Canada issued 2812 case reports with fentanyl detected; of these cases, approximately 45% (1261) were positive for at least one benzodiazepine drug. This study presents concentrations of both fentanyl and benzodiazepine drugs in post mortem blood collected from a visualized, ligated femoral vein. The study demonstrates that the blood concentration of fentanyl in benzo-dope case reports is considerably higher than in cases where no benzodiazepine drug was detected.The median concentration of fentanyl in femoral blood for cases that also contained a benzodiazepine drug was 12.4 ng/mL (2020), 11.9 ng/mL (2021) and 14.0 ng/mL (2022). The median concentration of fentanyl in femoral blood for cases that did not contain a benzodiazepine drug was 8.5 ng/mL (2020), 7.0 ng/mL (2021) and 7.2 ng/mL (2022). The percent differences between the groups were similar with those observed from quantitative analysis of drug powders from unrelated police seizures in Alberta, Canada, suggesting the observed differences in blood fentanyl concentration may be due to the use of a drug substance with a higher concentration of fentanyl.Furthermore, the reported concentration of the benzodiazepine drug(s) is low, such that the role/contribution, if any, that this drug may have played in the decedents’ death should be questioned and carefully considered by the certifying medical examiner/coroner.

An individualized digital twin of a patient for transdermal fentanyl therapy for chronic pain management

Fentanyl transdermal therapy is a suitable treatment for moderate-to-severe cancer-related pain. The inter-individual variability of the patients leads to different therapy responses. This study aims to determine the effect of physiological features on the achieved pain relief. Therefore, a set of virtual patients was developed by using Markov chain Monte Carlo (MCMC) based on actual patient data. The members of this virtual population differ by age, weight, gender, and height. Tailored digital twins were developed using these correlated, individualized parameters to propose a personalized therapy for each patient. It was shown that patients of different ages, weights, and gender have significantly different fentanyl blood uptake, plasma fentanyl concentration, pain relief, and ventilation rate. In the digital twins, we included the virtual patients’ response to the treatment, namely, pain relief. Therefore, the digital twin was able to adjust the therapy in silico to have more efficient pain relief. By implementing digital-twin-assisted therapy, the average pain intensity decreased by 16% compared to conventional therapy. The median time without pain increased by 23 h over 72 h. Therefore, the digital twin can be successfully used in individual control of transdermal therapy to reach higher pain relief and maintain steady pain relief.Graphical (Created with BioRender.com)

Use of Liquid Chromatography--Tandem Mass Spectrometry to Quantify and Confirm the Fentanyl Metabolite N-[1-(2-Phenethy-4-Piperidinyl)] Maloanilinic Acid in Equine Urine for Doping Control.

Fentanyl, a powerful synthetic mu opioid receptor agonist, is banned in equine sports by the Association of Racing Commissioners International and the Fédération Équestre Internationale. The presence of fentanyl in equine blood has been confirmed during routine post-race screening for doping substances in the authors' laboratory. While fentanyl can be detected and confirmed in blood, it is rapidly metabolized, and screening for the metabolite N-[1-(2-phenethy-4-piperidinyl)] maloanilinic acid (PMA) in equine urine is expected to allow for a longer detection time. In this study, a quantitative and confirmatory liquid chromatography--tandem mass spectrometry (LC-MS-MS) method was developed for PMA analysis in equine urine. PMA was extracted by solid phase extraction, separated on a C18 column and detected using a triple quadrupole mass spectrometer. The mass spectrometer was operated in positive-ion mode, and multiple reaction monitoring was used to monitor product ions m/z 188, m/z 281 and m/z 323. The method was validated for extraction recovery, matrix effect, specificity, sensitivity, precision and accuracy, carryover and processed sample stability according to the guidelines of the US Food and Drug Administration for bioanalysis. The limits of detection and quantification were 5 and 10 pg/mL, respectively. Linearity was obtained over the concentration range of 10-10,000 pg/mL. To confirm PMA in equine urine, LC retention time, diagnostic product ions (m/z 188, m/z 281 and m/z 323) and product ion ratio were used as the criteria. The lowest concentration for confirmatory analysis was validated at 50 pg/mL. The method was applied to measure the PMA concentrations in equine urine following intravenous administration of fentanyl to a research horse and has confirmed the presence of PMA in post-race urine samples. This method is a valuable addition to the arsenal of equine doping control methods to combat illegal doping and protect racehorse health.

Interactions of fentanyl with blood platelets and plasma proteins: platelet sensitivity to prasugrel metabolite is not affected by fentanyl under in vitro conditions

BackgroundClinical trials indicate that fentanyl, like morphine, may impair intestinal absorption and thus decrease the efficacy of oral P2Y12 inhibitors, such as clopidogrel, ticagrelor, and prasugrel. However, the ability of fentanyl to directly negate or reduce the inhibitory effect of P2Y12 receptor antagonists on platelet function has not been established. A series of in vitro experiments was performed to investigate the ability of fentanyl to activate platelets, potentiate platelet response to ADP, and/or diminish platelet sensitivity to prasugrel metabolite (R-138727) in agonist-stimulated platelets. The selectivity and specificity of fentanyl toward major carrier proteins has been also studied.MethodsBlood was obtained from healthy volunteers (19 women and 12 men; mean age 40 ± 13 years). Platelet function was measured in whole blood, platelet-rich plasma and in suspensions of isolated platelets by flow cytometry, impedance and optical aggregometry. Surface plasmon resonance and molecular docking were employed to determine the binding kinetics of fentanyl to human albumin, α1-acid glycoprotein, apolipoprotein A-1 and apolipoprotein B-100.ResultsWhen applied at therapeutic and supratherapeutic concentrations under various experimental conditions, fentanyl had no potential to stimulate platelet activation and aggregation, or potentiate platelet response to ADP, nor did it affect platelet susceptibility to prasugrel metabolite in ADP-stimulated platelets. In addition, fentanyl was found to interact with all the examined carrier proteins with dissociation constants in the order of 10–4 to 10–9 M.ConclusionsIt does not seem that the delayed platelet responsiveness to oral P2Y12 inhibitors, such as prasugrel, in patients undergoing percutaneous coronary intervention, results from direct interactions between fentanyl and blood platelets. Apolipoproteins, similarly to albumin and α1-acid glycoprotein, appear to be important carriers of fentanyl in blood.

Atypical Fentanyl Transdermal Patch Consumption and Fatalities: Case Report and Literature Review

Fentanyl is a synthetic L-opioid receptor agonist, approximately 100 times more potent than morphine, that is experiencing an upward trend in the field of abuse. Fentanyl patches' abusive consumption can occur either by transdermal absorption or through other atypical and ingenious routes. In the present case, a 29-year-old man with a history of illicit drug use was found dead in a suburban neighborhood of an Italian city. At autopsy, lungs appeared increased in weight and showed minute subpleural hemorrhages. Airways contained abundant reddish foamy material; in addition, a fentanyl patch protective film was found inside the left main bronchus. Toxicological analysis revealed the presence of morphine, fentanyl, BEG and ethyl alcohol in peripheric blood; 6-MAM was also revealed in urine. Findings collected during post-mortem investigations allowed us to identify fentanyl consumption as the cause of death. Fentanyl consumption presumably took place by chewing of a transdermal patch, with subsequent aspiration of the protective film. The pathophysiology of death can be identified as combined respiratory failure-both central suppression and a fentanyl-induced increase in muscular stiffness; a further minor contribution may be identified in the mechanical airflow obstruction caused by the presence of the protective film at the bronchial level.

Fentanyl pharmacokinetics in blood of cancer patients by Gas Chromatography – Mass Spectrometry

In order to find a correlation between Fentanyl action on pain and inter-individual variability in different cancer patients, the pharmacokinetic characterization of the drug becomes essential. Therefore, a gas chromatographic–mass spectrometric (GC–MS) in SIM mode analytical procedure has been developed and validated for the determination of Fentanyl in human blood. The sample preparation consisted of a liquid-liquid extraction (LLE) from whole blood. The analysis were carried out with Agilent 7820 A series gas chromatograph equipped with a 5977E series mass selective single quadrupole detector (MSD) with an electron impact (EI) source (70 eV), under a temperature gradient elution. The limit of detection (LoD) and the limit of quantification (LoQ) values were found to be 5.60E-02 ± 3.50E-02 ng mL−1 and 1.86E-01 ± 1.18E-01 ng mL−1 respectively. The developed method was found selective and sensitive and therefore suitable for a fast determination of Fentanyl in human blood and for its pharmacokinetic characterization. Blood samples from 31 cancer patients treated with transdermal Fentanyl (doses in the range of 12–100 µg h−1) were collected at fixed intervals during an overall exposure time of 72 h. The analysis of data and the pharmacokinetic parameters revealed dissimilar pharmacokinetic profiles in the patients examined. Patients were therefore grouped in three categories representing the different trends observed: high, medium and slow responders. These preliminary data provided significant outcomes for a correlation to clinical response.

Pupil Light Reflex for the Assessment of Analgesia in Critically Ill Sedated Patients With Traumatic Brain Injury: A Preliminary Study.

BACKGROUND: Analgesia monitoring is essential to preserve comfort in critically ill sedated patients with traumatic brain injury (TBI). Although pupil dilation (PD) and pain behaviors can be used to assess analgesia, these indicators require application of noxious stimulations for elicitation. Recently, the pupillary light reflex (PLR) has emerged as a nonnoxious parameter that may be used to predict analgesia requirements in non-brain-injured patients. Here, we explored whether PLR can be used for the purpose of analgesia monitoring in critically ill sedated TBI patients. METHODS: Fifteen mechanically ventilated TBI patients (11 men; 54 ± 20 years) under continuous analgesia and sedation infusions were assessed at predefined time within 72 hours of intensive care unit admission. Data collection was performed using video-pupillometry and the Behavioral Pain Scale. At each assessment, pupil size and PLR at rest were recorded followed immediately by the documentation of PD and pain behaviors elicited by a calibrated noxious stimulus. Blood concentrations of analgesics/sedatives were monitored. RESULTS: One hundred three assessments were completed. PLR resulted in an average decrease of 19% in pupil diameter, and PD resulted in an average increase of 10% in pupil diameter. Variations in PLR and PD were more pronounced in subjects who showed a Behavioral Pain Scale score greater than 3 (a recognized sign of subanalgesia) compared with those with no behavioral reaction. Multiple regression analyses suggest a significant overlap between fluctuations in pupillary reflexes and blood levels of fentanyl, not propofol. CONCLUSION: In our sample, percentages of variation in PLR and PD were found to be directly representative of TBI patients' fentanyl blood concentration. Considering information about blood drug concentration is generally not available at bedside, PLR could be used as a proxy to assess analgesia requirements before a nociceptive procedure in critically ill sedated TBI patients who are vulnerable to stress.

Sentanyl: a comparison of blood fentanyl concentrations and naloxone dosing after non-fatal overdose

Introduction Non-pharmaceutical fentanyl and its analogs have driven striking increases in opioid-associated overdose deaths. These highly potent opioids can be found at low concentrations in biological specimens. Little is known regarding the concentrations of these substances among survivors of non-fatal overdoses. In a locale where fentanyl is responsible for the majority of non-fatal opioid overdoses, we compared the concentration of fentanyl in blood to naloxone dosing in the presence and absence of a concurrent sedative-hypnotic exposure. Methods In this pilot study, we enrolled adult patients presenting to the emergency department (ED) who: (1) arrived after an overdose requiring naloxone for the reversal of respiratory depression; and (2) who required venipuncture or intravenous access as part of their clinical care. Blood specimens (n = 20) underwent comprehensive toxicology testing, including the quantitation of fentanyl, fentanyl analogs, and naloxone, as well as the detection of common sedative-hypnotics and a wide range of other illicit and pharmaceutical substances. We then compared fentanyl concentrations to naloxone dosing in participants with and without a concomitant sedative-hypnotic exposure. Results Nineteen of twenty participants (95%) were exposed to fentanyl prior to their overdose; the remaining participant tested positive for heroin metabolites. No participants reported pharmaceutical fentanyl use. Fentanyl analogs – acetylfentanyl or carfentanil – were present in three specimens. In 11 cases, fentanyl and its metabolites were the only opioids identified. Among the fentanyl-exposed, blood concentrations ranged from <0.1–19 ng/mL with a mean of 6.2 ng/mL and a median of 3.6 ng/mL. There was no relationship between fentanyl concentration and naloxone dose administered for reversal. We detected sedative-hypnotics (including benzodiazepines, muscle relaxants, and antidepressants) in nine participants. Among the sedative-hypnotic exposed, fentanyl concentrations were lower, but naloxone dosing was similar to those without a concomitant exposure. Conclusions In this study, we found that: 1) fentanyl was present in the blood of nearly all participants; 2) fentanyl concentrations were lower among study participants with concomitant sedative-hypnotic exposure; and 3) the dose of naloxone administered for overdose reversal was not associated with the measured fentanyl concentration in blood specimens. Our results underscore the role that tolerance and concomitant drug exposure play in the precipitation and resuscitation of management of opioid overdose.

Causes, Nature and Toxicology of Fentanyl-Associated Deaths: A Systematic Review of Deaths Reported in Peer-Reviewed Literature.

PurposeFentanyl poisoning has been widely reported, yet there is a lack of systematic evaluation of the nature and toxicology of associated deaths in the published literature. This article aims to systematically review the nature, causes, routes of administration and toxicology of fentanyl-associated deaths using case studies and case series in peer-reviewed published literature.MethodsFour electronic databases including Embase, Medline (via Ovid), Scopus and Google Scholar were searched from inception until October 2019 to identify the studies reporting fentanyl related deaths. Two independent reviewers screened and selected the titles and then evaluated the full texts. Only case studies and case series were included. A structured data extraction tool was used to extract data on the number of deaths, routes of administration, concomitant drug use and toxicological data. The Joanna Briggs Institute quality assessment tool was used to evaluate the quality of included studies. Data were synthesized narratively.ResultsOf 1251 articles identified during initial search, 8 case reports and 9 case series met the inclusion criteria. A total of 1969 deaths were reported in the included studies. Deaths were concentrated in the north American region (n = 1946) and the Nordic region (n = 22). Reported causes of death included fentanyl overdose (n = 321, 56.4%), mixed drug toxicity (n = 196, 34.5%), natural (n = 28, 4.9%), other drug toxicity (n = 10, 1.8%), fentanyl and ethanol intoxication (n = 8, 1.4%), incidental (n = 5, <1%) and aspiration (n = 1). Most common routes of use were intravenous (70.5%) and transdermal routes (23.0%). Deaths came swiftly via the intravenous route. Mean level of blood fentanyl amongst all reported deaths was 0.024 µg/mL.ConclusionLiterature related to fentanyl-associated deaths predominantly come from North America. Deaths are comparatively lower or not reported in peer-reviewed publications from the rest of the world. Abuse through intravenous administration, mixed drug toxicities and self-treatment of breakthrough pain are mainly responsible for majority of the reported deaths.

A Novel Bioanalytical Method for the Determination of Opioids in Blood and Pericardial Fluid.

Opioids are the drugs most commonly detected in overdose deaths and the second most consumed worldwide. An analytical methodology has been optimized and fully validated for the determination of codeine, morphine, 6-acetylmorphine, 6-acetylcodeine, oxycodone, oxymorphone and fentanyl in whole blood and pericardial fluid. The internal standards used were codeine-d3, morphine-d3, 6-acetylmorphine-d3 and fentanyl-d5. Before solid-phase extraction, volumes of 250μL of blood and pericardial fluid were subjected to a protein precipitation (with 750μL of ice-cold acetonitrile) and a microwave-induced oximation was performed using a solution of 1% aqueous hydroxylamine hydrochloride in phosphate-buffered saline (1:2, v/v). Finally, the dried extracts were further derivatized with a solution of n-methyl-n-(trimethylsilyl) trifluoroacetamide+5% trimethylchlorosilane under microwave irradiation. The chromatographic analysis was carried out using gas chromatography-mass spectrometry operating in electron impact and selected ion monitoring mode. For all analytes, the method was linear between 5 and 1,000ng/mL with determination coefficients (r2) >0.99. Depending on the analyte and matrix, the limit of detection varies between 3 and 4ng/mL. Intra- and intermediate precision (<20%) and bias (±20%) were acceptable for all analytes in both matrices. The stability of the substances in the studied matrices was guaranteed, at least, 24h in the autosampler, 4h at room temperature and 30days after three freeze/thaw cycles. This methodology was applied to real samples from the Laboratory of Chemistry and Forensic Toxicology, Centre Branch, of the National Institute of Legal Medicine and Forensic Sciences, Portugal.

Understanding the Method and Results from the Analysis of Fentanyl in Postmortem Blood Using Biocompatible Solid-Phase Microextraction

The use of the Biocompatible Solid-Phase Microextraction (BioSPME) fiber in Grant et al. original work was to create an analysis method that is faster and simpler in identifying fentanyl in postmortem blood than current analysis methods. While the study was able to demonstrate that fentanyl was able to be absorbed onto the fiber and analyzed through the use of GC-MS and LC-MS-MS, the data reported was beyond the sensitivity for both instruments. The purpose of this communication is to provide more information regarding the methodology and sensitivity for both instruments and to reinterpret the data when comparing to the results from Health Network Laboratories. Based on the reinterpreted data, this current method was consistent with the results from Health Network Laboratories in identifying fentanyl in postmortem blood concentration equal to or greater than 21.4 ng/mL.

Investigation into the Analysis of Fentanyl in Postmortem Blood using Biocompatible Solid-Phase Microextraction

Over recent years, the abuse of fentanyl and other opioids has become a slow motion mass disaster in the United States resulting in an increased number of drug-related deaths. Various postmortem biological samples are collected by forensic pathologists during autopsy and then sent to a toxicology laboratory to be analyzed for the presence of various compounds such as fentanyl. This process can be time consuming and results in a backlog, potentially hindering an investigation. A possible solution is Biocompatible Solid-Phase MicroExtraction (BioSPME) fibers. These fibers can be directly inserted into a biological matrix and absorb drug compounds without the interference of macromolecules that may be present allowing for a faster analysis time. An initial method has been developed to analyze fentanyl in postmortem blood using BioSPME followed by GC-MS and LC-MS-MS analysis. BioSPME fibers were conditioned, washed, directly inserted into postmortem blood, washed, filtered, desorbed into solution, dried down and reconstituted. The extracted samples were screened by GC-MS and subsequently analyzed by LC-MS-MS. GC-MS was performed using splitless injection on a Rxi-5Sil MS column (30.0 m × 0.25 mm, 0.25 μm) in the SIM mode. Samples were confirmed using an AB SCIEX™ 3200 QTRAP® triple quadrupole mass spectrometer with ElectroSpray Ionization (ESI) source in the positive ion mode. Liquid Chromatography was performed on a Shimadzu® LC system using an Ascentis® Express Biphenyl column (50 mm × 2.1 mm, 2.7 μm) with the weak mobile phase of 0.1%(v/v) formic acid in water and the strong mobile phase of 0.1%(v/v) formic acid in acetonitrile for an analysis time of seven min per sample. This method was developed using bovine blood and then applied to 43 postmortem blood samples provided by the Lehigh County Coroner’s Office (Allentown, PA, USA).