Risk factors for severe respiratory depression from prescription opioid overdose

A systematic analysis and data mining of opioid-related adverse events submitted to the FAERS database

The opioid epidemic has become a serious national crisis in the United States. An indepth systematic analysis of opioid-related adverse events (AEs) can clarify the risks presented by opioid exposure, as well as the individual risk profiles of specific opioid drugs and the potential relationships among the opioids. In this study, 92 opioids were identified from the list of all Food and Drug Administration (FDA)-approved drugs, annotated by RxNorm and were classified into 13 opioid groups: buprenorphine, codeine, dihydrocodeine, fentanyl, hydrocodone, hydromorphone, meperidine, methadone, morphine, oxycodone, oxymorphone, tapentadol, and tramadol. A total of 14,970,399 AE reports were retrieved and downloaded from the FDA Adverse Events Reporting System (FAERS) from 2004, Quarter 1 to 2020, Quarter 3. After data processing, Empirical Bayes Geometric Mean (EBGM) was then applied which identified 3317 pairs of potential risk signals within the 13 opioid groups. Based on these potential safety signals, a comparative analysis was pursued to provide a global overview of opioid-related AEs for all 13 groups of FDA-approved prescription opioids. The top 10 most reported AEs for each opioid class were then presented. Both network analysis and hierarchical clustering analysis were conducted to further explore the relationship between opioids. Results from the network analysis revealed a close association among fentanyl, oxycodone, hydrocodone, and hydromorphone, which shared more than 22 AEs. In addition, much less commonly reported AEs were shared among dihydrocodeine, meperidine, oxymorphone, and tapentadol. On the contrary, the hierarchical clustering analysis further categorized the 13 opioid classes into two groups by comparing the full profiles of presence/absence of AEs. The results of network analysis and hierarchical clustering analysis were not only consistent and cross-validated each other but also provided a better and deeper understanding of the associations and relationships between the 13 opioid groups with respect to their adverse effect profiles.

A pilot study to identify pharmacogenomic and clinical risk factors associated with opioid related falls and adverse effects in older adults

Given the high prevalence of pain in older adults and current trends in opioid prescribing, inclusion of genetic information in risk prediction tools may improve opioid risk assessment. Our objectives were to (1) determine the feasibility of recruiting socioeconomically disadvantaged and racially diverse middle aged and older adult populations for a study seeking to identify risk factors for opioid-related falls and other serious adverse effects and (2) explore potential associations between the Risk Index for Overdose or Serious Opioid-induced Respiratory Depression (CIP-RIOSORD) risk class and other patient factors with falls and serious opioid adverse effects. This was an observational study of 44 participants discharged home from the emergency department with an opioid prescription for acute pain and followed for 30 days. We found pain interference may predict opioid-related falls or serious adverse effects within older, opioid-treated patients. If validated, pain interference may prove to be a beneficial marker for risk stratification of older adults initiated on opioids for acute pain.

Nighttime Sleep and Respiratory Disturbances in Individuals Receiving Methadone to Treat Opioid Use Disorder

ABSTRACT

Opioids are a leading cause of drug overdose deaths in the United States. Methadone used as medication for opioid use disorder (MOUD) reduces drug cravings and promotes abstinence. However, individuals in methadone-based MOUD treatment commonly report subjective sleep complaints and are at risk for respiratory depression from opioids. We investigated nighttime sleep and respiratory function in eight individuals (six women, two men; ages 31-68 years) in their first 90 days of methadone-based MOUD treatment. Participants underwent overnight cardiorespiratory polysomnography. Sleep and respiratory variables were characterized with descriptive statistics for comparison to reference data from similarly aged healthy adults. Although participants spent 8.1 ± 0.3 hours (mean ± SD ) in bed, their total sleep time was only 6.8 ± 1.3 hours. They exhibited longer sleep latency and intermittent wakefulness. Sleep structure was irregular, with disrupted sleep cycles. Participants also displayed a decreased amount of N1 sleep and an increased amount of N3 sleep, compared with reference data. Participants showed respiratory depression, with an average apnea-hypopnea index of 16.5 ± 8.9 events per hour. Central sleep apneas comprised 69.1% ± 20.9% of the respiratory events. A Cheyne-Stokes-like breathing pattern, consisting of 30-second cycles of three central sleep apneas, was observed in 75% of participants. Our results suggest that individuals early in methadone-based MOUD treatment experience disordered sleep and respiratory disturbances. Such nighttime physiological changes may have serious long-term health consequences and contribute to unintended overdose rates. Identifying and treating MOUD individuals with sleep apnea could reduce risk of death.

Piloting Smart Home Sensors to Detect Overnight Respiratory and Withdrawal Symptoms in Adults Prescribed Opioids

BACKGROUND

Novel strategies are needed to curb the opioid overdose epidemic. Smart home sensors have been successfully deployed as digital biomarkers to monitor health conditions, yet they have not been used to assess symptoms important to opioid use and overdose risks.

AIM

This study piloted smart home sensors and investigated their ability to accurately detect clinically pertinent symptoms indicative of opioid withdrawal or respiratory depression in adults prescribed methadone.

METHODS

Participants (n = 4; 3 completed) were adults with opioid use disorder exhibiting moderate levels of pain intensity, withdrawal symptoms, and sleep disturbance. Participants were invited to two 8-hour nighttime sleep opportunities to be recorded in a sleep research laboratory, using observed polysomnography and ambient smart home sensors attached to lab bedroom walls. Measures of feasibility included completeness of data captured. Accuracy was determined by comparing polysomnographic data of sleep/wake and respiratory status assessments with time and event sensor data.

RESULTS

Smart home sensors captured overnight data on 48 out of 64 hours (75% completeness). Sensors detected sleep/wake patterns in alignment with observed sleep episodes captured by polysomnography 89.4% of the time. Apnea events (n = 118) were only detected with smart home sensors in two episodes where oxygen desaturations were less severe (>80%).

CONCLUSIONS

Smart home technology could serve as a less invasive substitute for biologic monitoring for adults with pain, sleep disturbances, and opioid withdrawal symptoms. Supplemental sensors should be added to detect apnea events. Such innovations could provide a step forward in assessing overnight symptoms important to populations taking opioids.

An integrated LSTM-HeteroRGNN model for interpretable opioid overdose risk prediction

Opioid overdose (OD) has become a leading cause of accidental death in the United States, and overdose deaths reached a record high during the COVID-19 pandemic. Combating the opioid crisis requires targeting high-need populations by identifying individuals at risk of OD. While deep learning emerges as a powerful method for building predictive models using large scale electronic health records (EHR), it is challenged by the complex intrinsic relationships among EHR data. Further, its utility is limited by the lack of clinically meaningful explainability, which is necessary for making informed clinical or policy decisions using such models. In this paper, we present LIGHTED, an integrated deep learning model combining long short term memory (LSTM) and graph neural networks (GNN) to predict patients' OD risk. The LIGHTED model can incorporate the temporal effects of disease progression and the knowledge learned from interactions among clinical features. We evaluated the model using Cerner's Health Facts database with over 5 million patients. Our experiments demonstrated that the model outperforms traditional machine learning methods and other deep learning models. We also proposed a novel interpretability method by exploiting embeddings provided by GNNs to cluster patients and EHR features respectively, and conducted qualitative feature cluster analysis for clinical interpretations. Our study shows that LIGHTED can take advantage of longitudinal EHR data and the intrinsic graph structure of EHRs among patients to provide effective and interpretable OD risk predictions that may potentially improve clinical decision support.

Prescription drug and alcohol simultaneous co-ingestion in U.S. young adults: Prevalence and correlates

Simultaneous co-ingestion of prescription medication (e.g., opioid, tranquilizer/sedative, stimulant) and alcohol is associated with overdose and elevated substance use, but no studies have examined prescription drug misuse (PDM) and alcohol co-ingestion in U.S. young adults (18-25 years), despite the high rates of PDM in this age group. We used the 2015-19 National Survey on Drug Use and Health (young adult N = 69,916) to examine prevalence of past-month PDM-alcohol co-ingestion, PDM characteristics, and sociodemographic, physical health, mental health, and substance use correlates. Logistic regression examined correlates, comparing those without past-year PDM, those with past-year but not past-month PDM, those with past-month PDM without alcohol co-ingestion, and those with past-month PDM and alcohol co-ingestion. An estimated 585,000 young adults engaged in any past-month PDM-alcohol co-ingestion, or between 32.7% (opioids) and 44.6% (tranquilizer/sedatives) of those who were engaged in past-month PDM. Co-ingestion varied by educational status and was more common in males and white or multiracial young adults. All PDM-involved groups had elevated odds of suicidal ideation and other psychopathology, but substance use and substance use disorder (SUD) odds were significantly higher in young adults with co-ingestion, versus all other groups. To illustrate, 41.1% with opioid-alcohol co-ingestion had multiple past-year SUDs, versus 2.0% in those without past-year PDM. Young adults with co-ingestion are particularly likely to have problematic alcohol use and higher rates of SUD. Counseling about the risks of PDM-alcohol co-ingestion and screening for co-ingestion among those at risk are warranted to limit poor outcomes. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Modeling of overdose and naloxone distribution in the setting of fentanyl compared to heroin

BACKGROUND

Fentanyl has replaced most other non-prescribed opioids in much of North America. There is controversy over whether a hypothetical reduced efficacy of naloxone in reversing fentanyl is a major contributor to the coincident rising overdose mortality.

METHODS

We modified an existing Markov decision analytic model of heroin overdose and naloxone distribution to account for known risks of fentanyl by adjusting overdose risk, the likelihood of death in the event of overdose, and the proportion of cases in which available naloxone was administered in time to prevent death. We assumed near-universal survival when naloxone was administered promptly for heroin or fentanyl overdose, but allowed that to decline in sensitivity analyses for fentanyl. We varied the proportion of use that was fentanyl and adjusted the modified parameters accordingly to estimate mortality as the dominant opioid shifted.

RESULTS

Absent naloxone, the annual overdose death rate was 1.0% and 4.1% for heroin and fentanyl, respectively. With naloxone reaching 80% of those at risk, the overdose death rate was 0.7% and 3.6% for heroin and fentanyl, respectively, representing reductions of 26.4% and 12.0%. Monte Carlo simulations resulted in overdose mortality with fentanyl of 3.3-5.2% without naloxone and 2.6-4.9% with naloxone, with 95% certainty. Positing reduced efficacy for naloxone in reversing fentanyl resulted in 3.6% of fentanyl overdose deaths being prevented by naloxone.

CONCLUSIONS

Heightened risk for overdose and subsequent death, alongside the time-sensitive need for naloxone administration, fully account for increased mortality when fentanyl replaces heroin, assuming optimal pharmacologic efficacy of naloxone.

Opioid Dosage Levels, Concurrent Risk Factors and Self-Perceptions among Chronic Pain, Opioid-Managed Individuals at Elevated Risk for Opioid Overdose

While current opioid prescribing guidelines highlight a dose-response relationship between therapeutic management and overdose risk, other concurrent risk factors have also been identified. However, there is little data in assessing the relationship between risk factor prevalence, associated provider communication, and subsequent perceptions of overdose risk among chronic pain, opioid-managed (CPOM) patients. An online questionnaire was distributed in June 2020 to a sample of CPOM individuals (n = 190) treated with an opioid prescription at or above 50 daily MME, or any dosage alongside benzodiazepines. CPOM individuals reported a mean daily MME of 470, with half (52.6%) receiving a concurrent benzodiazepine prescription. All patients reported past month alcohol use, and 67.4% indicated a risk-elevating diagnosed medical condition. In assessing provider communication, 41.6% reported no discussion focusing on the risks of one’s opioid therapy. Subsequently, 62.1% perceived themselves as having “no risk”, and 60.0% were “not at all concerned” (60.0%) about experiencing an opioid overdose. Organizational policies should focus on implementing consistent methods of patient education regarding overdose risk, as well as assessments of behaviors or characteristics that my increase an individual’s risk of opioid overdose. These policies should also include other forms of evidence-based overdose risk prevention such as co-prescriptions of naloxone.

Prescription opioid policies and associations with opioid overdose and related adverse effects

BACKGROUND

United States (US) policies to mitigate the opioid epidemic focus on reducing access to prescription opioids to prevent overdoses. We examined the impact of state policies in Vermont (July 2017) and Maine (July 2016) on opioid overdoses and opioid-related adverse effects.

METHODS

Study population included patients 15 years and older in all-payer claims of Vermont (N = 597,683; Jan.2016-Dec.2018) and Maine (N = 1,370,960; Oct.2015-Dec.2017). We used interrupted time series analyses to assess the impact of opioid prescribing policies on monthly opioid overdose rate and opioid-related adverse effects rate. We used the International Classification of Disease-10-CM to identify overdoses (T40.0 × 1-T40.4 × 4, T40.601-T40.604, T40.691-T40.694) and adverse effects (T40.0 × 5, T40.2 × 5-T40.4 × 5, T40.605, T40.695).

RESULTS

Immediately after the policy, the level of Vermont's opioid overdose rate increased by 34% (95% confidence interval, CI: 1.09, 1.65) while the level of opioid-related adverse effects rate decreased by 29% (95% CI: 0.58, 0.87). In Maine, there was no level change in opioid overdose rate, but the slope of the adverse effects rate after the policy decreased by 3.5% (95% CI: 0.94, 0.99). These results varied within age and rurality subgroups in both states.

CONCLUSION

While the decrease in rate of adverse effects following the policy changes is promising, the increase in Vermont's opioid overdose rate may suggest there is an association between policy implementation and short-term risk to public health.

Co-ingestion of prescription drugs and alcohol in US adults aged 50 years or older

OBJECTIVE

To examine prevalence of past-month prescription drug misuse (PDM) and alcohol co-ingestion and its correlates in adults age 50 or older.

METHODS

Data were from the 2015-2018 US National Survey on Drug Use and Health (n = 35,190). PDM-alcohol co-ingestion was defined as prescription opioid, tranquilizer/sedative, or stimulant misuse while "drinking alcohol or within a couple of hours of drinking." Co-ingestion prevalence was estimated, and logistic and negative binomial regressions examined the sociodemographic, physical health, mental health, substance use, and substance use disorder (SUD) correlates of co-ingestion.

RESULTS

Over 344,000 adults aged 50 years or older (0.3%) engaged in past-month PDM-alcohol co-ingestion, or 27.4% of those with past-month PDM. Past-month co-ingestion was linked to greater past-month alcohol use frequency and elevated adjusted odds ratios (aORs) for all examined substance use outcomes (e.g., non-PDM SUD aOR = 21.8; 49.7% prevalence rate). The aOR for suicidal ideation was 506% higher in those with co-ingestion than those without past-year PDM.

CONCLUSIONS

US adults aged 50 years or older with past-month PDM-alcohol co-ingestion are at high risk for SUD and concerning mental health symptoms. Screening for mental health and substance use treatment is warranted among aging adults with signs of PDM, especially involving co-ingestion.

Unintentional Opioid Overdoses Treated at University Clinic of Toxicology-Skopje in a Nine-Year-Period

BACKGROUND

The aim of this study was to assess the epidemiological profile of unintentional opioid overdoses, the prevalence and number of psychotropic substances involved in opioid overdoses.

METHODS

This was a descriptive study, in which 180 participants were enrolled, and covered a nine-years-period. For collecting data was used the National patient electronic system "My term". The variables as gender, age, duration of opioid dependence, number of overdoses, type of substance, number of antidote ampoules, duration of hospitalization were analyzed. Severity of poisoning was made by using the Poison severity score.

RESULTS

Opioid overdose cases were significantly higher among males than females. Mean age with standard deviation (SD) was 32.23 ± 6.71 years. Mean years (±SD) of duration of opioid use disorder was 11.60 ± 5.89 years. The most commonly used primary substance was methadone in 68.89% and heroin in 31.11% cases. Twenty patients were treated with mechanical ventilation because of the severe respiratory depression. Poison severity score was moderate in 51.11%, severe in 45.56% and fatal in 3.33% of the cases.

CONCLUSION

Most of the cases, predominantly males used one or two substances. The combination of methadone and benzodiazepine was most frequently used and the most common way was by injecting the abused substances. In most of the subjects PSS score was moderate and severe with no differences between genders.

Multimodal Nonopioid Pain Protocol Provides Equivalent Pain Versus Opioid Control Following Meniscus Surgery: A Prospective Randomized Controlled Trial

PURPOSE

To assess the effectiveness of a nonopioid pain regimen in controlling postoperative pain as compared with a traditional opioid pain control following primary meniscectomy or meniscal repair.

METHODS

Ninety-nine patients undergoing primary meniscectomy or meniscal repair were assessed for participation. A prospective randomized control trial was performed in accordance with the Consolidated Standards of Reporting Trials 2010 statement. The 2 arms of the study included a multimodal nonopioid analgesic protocol and a standard opioid regimen with a primary outcome of postoperative pain level (visual analog scale) for the first 10 days postoperatively. Secondary outcomes included patient-reported outcomes, complications, and patient satisfaction. Randomization was achieved using a random-number generator. Patients were not blinded. Data collection was done by a blinded observer.

RESULTS

Eleven patients did not meet the inclusion criteria, and 27 declined participation. A total of 61 patients were analyzed with 30 randomized to the opioid regimen and 31 randomized to the nonopioid regimen. Patients receiving the nonopioid regimen demonstrated noninferior visual analog scale scores compared with patients who received opioid pain medication (P > .05). No significant differences were found in preoperative (opioid: 58.9 ± 7.0; nonopioid: 58.2 ± 5.5, P = .724) or postoperative (opioid: 59.8 ± 6.5; nonopioid: 54.9 ± 7.1, P = .064) Patient-Reported Outcomes Measurement and Information System Pain Interference Short Form scores. No difference was found in recorded side effects between both groups at any given time point: constipation, nausea, diarrhea, upset stomach, and drowsiness (P > .05).

CONCLUSIONS

This study found that a multimodal nonopioid pain protocol provided equivalent pain control and patient outcomes following primary meniscus surgery while having an equivalent side effect profile. All patients reported satisfaction with their pain management without requiring emergency opioid analgesia.

LEVEL OF EVIDENCE

Level I, prospective randomized controlled trial.

Long-lasting agony and failure to provide assistance in a case of mixed methadone-prescription drugs acute intoxication

Methadone overdoses are usually considered "slow" and avoidable deaths. Despite being frequently witnessed, the type and duration of the agonal time are rarely documented and challenging to be reconstructed. Here we report a case in which a young male was found dead in a parked car, shortly after discharge from a compulsory psychiatric treatment. Death scene investigation, clinical records collection, analysis of video recordings from surveillance cameras and private videos, post-mortem examination, GC-MS and LC-MS/MS toxicological analyses were performed and allowed to assess an acute fatal intoxication by methadone and prescription drugs. The case here-in reported is a rare example of a witnessed and recorded prolonged agonal phase due to methadone and drug intoxication, which lasted at least 12 hours. The loss of consciousness and a worsening pattern of respiratory depression, including gasping, were reported by the friends of the victim, but no one called for help, arising the suspect of failure to provide assistance. The possibility of a long-lasting agony with respiratory gasping should be considered in the evaluation of similar intoxication cases.

A Large-Scale Observational Study on the Temporal Trends and Risk Factors of Opioid Overdose: Real-World Evidence for Better Opioids

Background

The USA is in the midst of an opioid overdose epidemic. To address the epidemic, we conducted a large-scale population study on opioid overdose.

Objectives

The primary objective of this study was to evaluate the temporal trends and risk factors of inpatient opioid overdose. Based on its patterns, the secondary objective was to examine the innate properties of opioid analgesics underlying reduced overdose effects.

Methods

A retrospective cross-sectional study was conducted based on a large-scale inpatient electronic health records database, Cerner Health Facts^®, with (1) inclusion criteria for participants as patients admitted between 1 January, 2009 and 31 December, 2017 and (2) measurements as opioid overdose prevalence by year, demographics, and prescription opioid exposures.

Results

A total of 4,720,041 patients with 7,339,480 inpatient encounters were retrieved from Cerner Health Facts^®. Among them, 30.2% patients were aged 65+ years, 57.0% female, 70.1% Caucasian, 42.3% single, 32.0% from the South, and 80.8% in an urban area. From 2009 to 2017, annual opioid overdose prevalence per 1000 patients significantly increased from 3.7 to 11.9 with an adjusted odds ratio (aOR): 1.16, 95% confidence interval (CI) 1.15–1.16. Compared to the major demographic counterparts, being in (1) age group: 41–50 years (overall aOR 1.36, 95% CI 1.31–1.40) or 51–64 years (overall aOR 1.35, 95% CI 1.32–1.39), (2) marital status: divorced (overall aOR 1.19, 95% CI 1.15–1.23), and (3) census region: West (overall aOR 1.32, 95% CI 1.28–1.36) were significantly associated with a higher odds of opioid overdose. Prescription opioid exposures were also associated with an increased odds of opioid overdose, such as meperidine (overall aOR 1.09, 95% CI 1.06–1.13) and tramadol (overall aOR 2.20, 95% CI 2.14–2.27). Examination on the relationships between opioid analgesic properties and their association strengths, aORs, and opioid overdose showed that lower aOR values were significantly associated with (1) high molecular weight, (2) non-interaction with multi-drug resistance protein 1 or interaction with cytochrome P450 3A4, and (3) non-interaction with the delta opioid receptor or kappa opioid receptor.

Conclusions

The significant increasing trends of opioid overdose at the inpatient care setting from 2009 to 2017 suggested an ongoing need for efforts to combat the opioid overdose epidemic in the USA. Risk factors associated with opioid overdose included patient demographics and prescription opioid exposures. Moreover, there are physicochemical, pharmacokinetic, and pharmacodynamic properties underlying reduced overdose effects, which can be utilized to develop better opioids.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40801-021-00253-8.

Opioid-Associated Out-of-Hospital Cardiac Arrest: Distinctive Clinical Features and Implications for Health Care and Public Responses: A Scientific Statement From the American Heart Association

Opioid overdose is the leading cause of death for Americans 25 to 64 years of age, and opioid use disorder affects >2 million Americans. The epidemiology of opioid-associated out-of-hospital cardiac arrest in the United States is changing rapidly, with exponential increases in death resulting from synthetic opioids and linear increases in heroin deaths more than offsetting modest reductions in deaths from prescription opioids. The pathophysiology of polysubstance toxidromes involving opioids, asphyxial death, and prolonged hypoxemia leading to global ischemia (cardiac arrest) differs from that of sudden cardiac arrest. People who use opioids may also develop bacteremia, central nervous system vasculitis and leukoencephalopathy, torsades de pointes, pulmonary vasculopathy, and pulmonary edema. Emergency management of opioid poisoning requires recognition by the lay public or emergency dispatchers, prompt emergency response, and effective ventilation coupled to compressions in the setting of opioid-associated out-of-hospital cardiac arrest. Effective ventilation is challenging to teach, whereas naloxone, an opioid antagonist, can be administered by emergency medical personnel, trained laypeople, and the general public with dispatcher instruction to prevent cardiac arrest. Opioid education and naloxone distributions programs have been developed to teach people who are likely to encounter a person with opioid poisoning how to administer naloxone, deliver high-quality compressions, and perform rescue breathing. Current American Heart Association recommendations call for laypeople and others who cannot reliably establish the presence of a pulse to initiate cardiopulmonary resuscitation in any individual who is unconscious and not breathing normally; if opioid overdose is suspected, naloxone should also be administered. Secondary prevention, including counseling, opioid overdose education with take-home naloxone, and medication for opioid use disorder, is important to prevent recurrent opioid overdose.

γ-Hydroxybutyric Acid: Pharmacokinetics, Pharmacodynamics, and Toxicology

Gamma-hydroxybutyrate (GHB) is a short-chain fatty acid present endogenously in the brain and used therapeutically for the treatment of narcolepsy, as sodium oxybate, and for alcohol abuse/withdrawal. GHB is better known however as a drug of abuse and is commonly referred to as the "date-rape drug"; current use in popular culture includes recreational "chemsex," due to its properties of euphoria, loss of inhibition, amnesia, and drowsiness. Due to the steep concentration-effect curve for GHB, overdoses occur commonly and symptoms include sedation, respiratory depression, coma, and death. GHB binds to both GHB and GABAB receptors in the brain, with pharmacological/toxicological effects mainly due to GABAB agonist effects. The pharmacokinetics of GHB are complex and include nonlinear absorption, metabolism, tissue uptake, and renal elimination processes. GHB is a substrate for monocarboxylate transporters, including both sodium-dependent transporters (SMCT1, 2; SLC5A8; SLC5A12) and proton-dependent transporters (MCT1-4; SLC16A1, 7, 8, and 3), which represent significant determinants of absorption, renal reabsorption, and brain and tissue uptake. This review will provide current information of the pharmacology, therapeutic effects, and pharmacokinetics/pharmacodynamics of GHB, as well as therapeutic strategies for the treatment of overdoses. Graphical abstract.

The molecular neurobiology and neuropathology of opioid use disorder

The number of people diagnosed with opioid use disorder has skyrocketed as a consequence of the opioid epidemic and the increased prescribing of opioid drugs for chronic pain relief. Opioid use disorder is characterized by loss of control of drug taking, continued drug use in the presence of adverse consequences, and repeated relapses to drug taking even after long periods of abstinence. Patients who suffer from opioid use disorder often present with cognitive deficits that are potentially secondary to structural brain abnormalities that vary according to the chemical composition of the abused opioid. This review details the neurobiological effects of oxycodone, morphine, heroin, methadone, and fentanyl on brain neurocircuitries by presenting the acute and chronic effects of these drugs on the human brain. In addition, we review results of neuroimaging in opioid use disorder patients and/or histological studies from brains of patients who had expired after acute intoxication following long-term use of these drugs. Moreover, we include relevant discussions of the neurobiological mechanisms involved in promoting abnormalities in the brains of opioid-exposed patients. Finally, we discuss how novel strategies could be used to provide pharmacological treatment against opioid use disorder.

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Brain abnormalities caused by opioid intoxication.

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Intoxication of opioids leads to defects in brain neurocircuitries.

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Insight into the molecular mechanisms associated with craving in heroin addicts.

Current state of opioid stewardship

PURPOSE

The opioid epidemic continues to result in significant morbidity and mortality even within hospitals where opioids are the second most common cause of adverse events. Opioid stewardship represents one model for hospitals to promote safe and rational prescribing of opioids to mitigate preventable adverse events in alliance with new Joint Commission standards. The purpose of this study was to identify the prevalence of current hospital practices to improve opioid use.

METHODS

A cross-sectional survey of hospital best practices for opioid use was electronically distributed via electronic listservs in March 2018 to examine the presence of an opioid stewardship program and related practices, including formulary restrictions, specialist involvement for high-risk patients, types of risk factors screened, and educational activities.

RESULTS

Among 133 included hospitals, 23% reported a stewardship program and 14% reported a prospective screening process to identify patients at high risk of opioid-related adverse events (ORAEs). Among those with a prospective screening process, there was variability in ORAE risk factor screening. Formulary restrictions were dependent on specific opioids and formulations. Patient-controlled analgesia was restricted at 45% of hospitals. Most hospitals reported having a pain management service (90%) and a palliative care service providing pain management (67%).

CONCLUSION

The absence of opioid stewardship and prospectively screening ORAEs represents a gap in current practice at surveyed hospitals. Hospitals have an opportunity to implement and refine best practices such as access to pain management specialists, use of formulary restrictions, and retrospective and prospective monitoring of adverse events to improve opioid use.

Endogenous Opiates and Behavior: 2018

This paper is the forty-first consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2018 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (2), the roles of these opioid peptides and receptors in pain and analgesia in animals (3) and humans (4), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (5), opioid peptide and receptor involvement in tolerance and dependence (6), stress and social status (7), learning and memory (8), eating and drinking (9), drug abuse and alcohol (10), sexual activity and hormones, pregnancy, development and endocrinology (11), mental illness and mood (12), seizures and neurologic disorders (13), electrical-related activity and neurophysiology (14), general activity and locomotion (15), gastrointestinal, renal and hepatic functions (16), cardiovascular responses (17), respiration and thermoregulation (18), and immunological responses (19).

Monoclonal Antibodies Counteract Opioid-Induced Behavioral and Toxic Effects in Mice and Rats

Monoclonal antibodies (mAbs) and vaccines have been proposed as medical countermeasures to treat opioid use disorder (OUD) and prevent opioid overdose. In contrast to current pharmacotherapies (e.g., methadone, buprenorphine, naltrexone, and naloxone) for OUD and overdose, which target brain opioid receptors, mAbs and vaccine-generated polyclonal antibodies sequester the target opioid in the serum and reduce drug distribution to the brain. Furthermore, mAbs offer several potential clinical benefits over approved medications, such as longer serum half-life, higher selectivity, reduced side effects, and no abuse liability. Using magnetic enrichment to isolate opioid-specific B cell lymphocytes prior to fusion with myeloma partners, this study identified a series of murine hybridoma cell lines expressing mAbs with high affinity for opioids of clinical interest, including oxycodone, heroin and its active metabolites, and fentanyl. In mice, passive immunization with lead mAbs against oxycodone, heroin, and fentanyl reduced drug-induced antinociception and the distribution of the target opioid to the brain. In mice and rats, mAb pretreatment reduced fentanyl-induced respiratory depression and bradycardia, two risk factors for opioid-related overdose fatality. Overall, these results support use of mAbs to counteract toxic effects of opioids and other chemical threats. SIGNIFICANCE STATEMENT: The incidence of fatal overdoses due to the widespread access to heroin, prescription opioids, and fentanyl suggests that current Food and Drug Administration-approved countermeasures are not sufficient to mitigate the opioid epidemic. Monoclonal antibodies (mAbs) may provide acute protection from overdose by binding to circulating opioids in serum. Use of mAbs prophylactically, or after exposure in combination with naloxone, may reduce hospitalization and increase survival.

Increased risk of death with codeine use in the elderly over 85 years old and patients with respiratory disease: A case-control study using retrospective insurance claims database

To investigate the risk of mortality associated with exposure to codeine, considering various risk groups, using population-based national insurance claims data.National sample cohort data from the National Health Insurance Service of South Korea (2002-2013) was used in this case-control study. Cases were defined as patients with a death record between January 1, 2002 and December 31, 2013. Each case was matched to 10 controls based on age, sex, baseline comorbidities, and year of death. Definition of exposure was codeine prescription in 30 days prior to death and sensitivity analyses were performed for 15 and 60-day exposures. Adjusted odds ratios (aORs) with 95% confidence intervals (CIs) were estimated using conditional logistic regression adjusting for benzodiazepine, other opioids, anesthetics, hypnotics, CYP2D6 inducer, CYP3A4 inducer, and the Charlson comorbidity index.A total of 19,341 cases and 185,700 matched controls were included. The overall risk associated with codeine use and mortality risk was not significant (aOR 1.08, 95% CI 1.00-1.16). Sensitivity analyses with different exposure time window also presented similar insignificant results. However, in the subgroup analyses, codeine use was associated with an increased risk of mortality in the >85-year-old age group (aOR 2.38, 95% CI 1.26-4.48) and patients with respiratory disease (aOR 1.29, 95% CI 1.17-1.42).Although no statistically significant association was found in codeine exposure and mortality risk between cases and controls, we demonstrated that the elderly over 85 years old and patients with respiratory disease are associated with a higher risk with codeine exposure. Therefore, a more cautious practice of codeine prescription in these groups might be needed.

Emergency Department Visits for Opioid Overdoses Among Patients With Cancer

BACKGROUND

Patients with cancer may be at risk of high opioid use due to physical and psychosocial factors, although little data exist to inform providers and policymakers. Our aim is to examine overdoses from opioids leading to emergency department (ED) visits among patients with cancer in the United States.

METHODS

The Healthcare Cost and Utilization Project Nationwide Emergency Department Sample was queried for all adult cancer-related patient visits with a primary diagnosis of opioid overdose between 2006 and 2015. Temporal trends and baseline differences between patients with and without opioid-related ED visits were evaluated. Multivariable logistic regression analysis was used to identify risk factors associated with opioid overdose. All statistical tests were two-sided.

RESULTS

Between 2006 and 2015, there were a weighted total of 35 339 opioid-related ED visits among patients with cancer. During this time frame, the incidence of opioid-related ED visits for overdose increased twofold (P < .001). On multivariable regression (P < .001), comorbid diagnoses of chronic pain (odds ratio [OR] 4.51, 95% confidence interval [CI] = 4.13 to 4.93), substance use disorder (OR = 3.54, 95% CI = 3.28 to 3.82), and mood disorder (OR = 3.40, 95% CI = 3.16 to 3.65) were strongly associated with an opioid-related visit. Patients with head and neck cancer (OR = 2.04, 95% CI = 1.82 to 2.28) and multiple myeloma (OR = 1.73, 95% CI = 1.32 to 2.26) were also at risk for overdose.

CONCLUSIONS

Over the study period, the incidence of opioid-related ED visits in patients with cancer increased approximately twofold. Comorbid diagnoses and primary disease site may predict risk for opioid overdose.

Safety, Tolerability, and Dose Proportionality of a Novel Transdermal Fentanyl Matrix Patch and Bioequivalence With a Matrix Fentanyl Patch: Two Phase 1 Single-Center Open-Label, Randomized Crossover Studies in Healthy Japanese Volunteers

Two open‐label, single‐dose, randomized crossover studies were conducted in healthy Japanesemen to (1) assess dose proportionality of 5 doses (1.38, 2.75, 5.5, 8.25, and 11.0 mg) of Lafenta, a novel matrix‐type transdermal fentanyl patch with a rate‐controlling membrane; and (2) compare patch bioequivalence (11.0 mg) with a commercially available reference patch (Durotep MT Patch [16.8 mg]). Pharmacokinetics, adhesion performance, residual fentanyl, and safety parameters were assessed. Increases in mean AUC_0‐t and C_max after application of the test patch were dose proportional. The test patch (11.0 mg) was bioequivalent to the 16.8‐mg reference patch in terms of mean AUC_0‐inf, AUC_0‐t, and C_max. Residual fentanyl levels 72 hours postapplication were lower in the test than in the reference patch. Differences in adhesion performance between the test and the reference patch did not affect delivery efficacy and reliability of the novel matrix patch. Safety findings were in line with previous experiences with fentanyl. Both studies showed low variation in fentanyl exposure and delivery via the test patch. The test patch provided equivalent fentanyl exposure at a lower dose than the reference patch formulation with lower variability and the potential to lower medicinal waste.

Clinical characteristics and time trends of hospitalized methadone exposures in the United States based on the Toxicology Investigators Consortium (ToxIC) case registry: 2010-2017

Background

Methadone is well known for its long duration of action and propensity for mortality after an overdose. The present research was aimed at evaluating the clinical manifestations and time trends of methadone exposure in patients in US hospitals.

Methods

We queried the American College of Medical Toxicology’s Toxicology Investigators Consortium case registry for all cases of methadone exposure between January 1, 2010, and December 31, 2017. The collected information included demographic features, clinical presentations, therapeutic interventions, poisoning type (acute, chronic, or acute on chronic), and the reason(s) for exposure. Descriptive data and relative frequencies were used to investigate the participants’ characteristics.

Our data analysis was performed using SPSS version 19 and Prism software. The trends and clinical manifestations of methadone poisoning over the time period of the study were specifically investigated.

Results

Nine hundred and seventy-three patients who met our inclusion criteria, with a mean age of 41.9 ± 16.6 years (range: 11 months-78 years) were analyzed. Five hundred eighty-two (60.2%) were male. The highest rate of methadone poisoning was observed in 2013. There was an increasing rate of methadone exposures in 2010–2013, followed by a decline in 2014–2017. The most common clinical manifestations in methadone-poisoned patients were coma (48.6%) and respiratory depression (33.6%). The in-hospital mortality rate of methadone poisoning was 1.4%.

Conclusion

ToxIC Registry data showed that inpatient methadone exposures enhanced from 2010 to 2013, after which a reduction occurred in the years 2014 to 2017.

Trends in opioid prescribing in Estonia (2011-2017)

Our objective was to examine the trends and variation in opioid prescribing in Estonia from 2011 to 2017. This retrospective cross-sectional study is based on a nationwide prescription medicines database. We stratified the analysis by treatment indication (cancer vs noncancer pain). Between 2011 and 2017, annual opioid prescribing rates increased by 67% (from 82.9 to 138.6 prescriptions per 1000 population). The annual number of prescriptions per patient did not change substantially (from 2.94 in 2011 to 2.87 in 2017), and was higher among cancer patients (5.07 vs 2.67 annual prescriptions per cancer and noncancer patients, respectively, in 2017). The use of the most potent opioids (morphine, fentanyl) was higher in noncancer than in cancer patients. The use of prescription opioids is low, and raises concern about the potential undertreatment of cancer pain, in parallel with misuse of opioids for either noncancer pain or diversion.

Prescription Drug Histories among Drug Overdose Decedents in Delaware

Background: The US opioid epidemic largely featured deaths from prescribed medications during Wave 1 (1990-2010), but its progression since then has resulted more so from deaths to illegal opioids-such as heroin (Wave 2 - 2010-2013) and fentanyl (Wave 3 - 2013-present). As deaths to illegally manufactured fentanyl have increased, attention to the role of prescribed opioids may be waning. However, the shifting nature of today's opioid epidemic demands we monitor how both legal and illegal drugs are involved in overdose deaths. Objectives: The purpose of our study is to investigate the prescription drug (Rx) records of overdose death decedents to illuminate the continued role of prescribed medications in Wave 3 deaths. Methods: We matched drug overdose death data and prescription drug monitoring data to investigate the prescription drug records (i.e. types of opioids and other medications) of Delaware, USA, decedents who died from a drug overdose death between January 1, 2013, and March 31, 2015 (27 months). Results: Fentanyl decedents differed significantly from other decedents in prescribed medications, including the amount and proximity of opioid and Rx fentanyl prescriptions before death. These relationships held while controlling for demographic characteristics and contributing health conditions. Conclusions: Our findings show a continued presence of Rx opioids in overdose deaths and that those dying from fentanyl had different Rx records than those who died from other drugs. Continued monitoring of Rx drugs, improved toxicology testing and greater data access for more research should follow to inform effective interventions.

Emergency Department Initiation of Buprenorphine for Opioid Use Disorder: Current Status, and Future Potential

Patients experiencing the consequences of opioid use often present to the emergency department (ED) at times of crisis, such as following overdose or when in withdrawal. This highlights the important role of the ED in recognizing opioid use disorder and engaging these patients into ongoing treatment. Given the limited ability of the healthcare system to provide timely addiction treatment, initiation of therapy in the ED, with referral to long-term care, is associated with improved outcomes. The primary evidence-based treatment used in EDs for this indication is buprenorphine. Although clinicians may find the initiation of buprenorphine therapy daunting, it is straightforward and well-tolerated, and many of the barriers are surmountable. This article addresses these barriers, which include stigma, complicated pharmacology, and confusing regulations, and provides a basis for the use of buprenorphine in acute care clinical practice.

Characteristics and circumstances of heroin and pharmaceutical opioid overdose deaths: Comparison across opioids

BACKGROUND

Although much is known about the correlates of heroin overdose, less is known about pharmaceutical opioid (PO) overdose. This study aimed to examine correlates of opioid overdose deaths by opioid and compare correlates between opioids.

METHODS

Analysis of opioid overdose deaths in Australia between 2000-2015, extracted from the National Coronial Information System (NCIS). The NCIS is an online database of deaths reportable to the coroner, and contains coroner's findings, autopsy and toxicology reports. Deaths were categorized into mutually exclusive groups: 1) Heroin deaths; and 2) PO deaths (excluding heroin). PO deaths were examined by individual opioid.

RESULTS

There were 10,795 opioid overdose deaths over the study period. Relative to deaths occurring in major cities, deaths in regional/remote areas had 15.2 (95 % CI: 11.5-20.2) times the risk of being attributed to pharmaceutical fentanyl than heroin. Relative to deaths among people without a recorded history of chronic pain, deaths among people with a recorded history of chronic pain had a 1.9-10.7-fold increased risk of the death being attributed to POs than heroin. Deaths among people with a recorded history of substance use problems where the opioid was injected prior to death had 7.2 and 1.7 times the risk of being attributed to methadone and pharmaceutical fentanyl (respectively) than heroin.

CONCLUSIONS

Findings suggest the need to: educate PO consumers about the risks of overdose at the time of prescribing; increase coverage and engagement in opioid dependence treatment (particularly in regional/remote areas); and increase uptake of take-home naloxone to reduce opioid overdose mortality.

Pharmacokinetics of ropivacaine in elderly patients receiving fascia iliaca compartment block

Local anesthetic of ropivacaine was demonstrated to reduce the postoperative pain in elderly patients. This study investigated the pharmacokinetics of ropivacaine at different concentrations in elderly patients subjected to fascia iliaca compartment block. Forty patients with femoral neck fracture at American Society of Anesthesiologists (ASA) I-II status, undergoing fascia iliaca compartment block (FICB) were randomized to two groups receiving 0.7 ml/kg of solution containing 0.375% ropivacaine (group L) or 0.5% ropivacaine (group H). Samples of venous blood were obtained immediately at different time points after FICB, and the total and free plasma concentrations of ropivacaine were measured by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). Statistical analysis was carried out using a pharmacokinetic calculation program (DAS 3.0). Visual Analogue Scale (VAS) scores were significantly decreased after FICB in both groups, and VAS score in group H was lower compared with group L. The total maximum plasma concentration (C_max) and the free C_max of ropivacaine in group H was higher than that in group L (P<0.05). The decrease of the total and free plasma concentration was operation time-dependent. Neither group showed signs of central nervous system and circulatory system toxicity. On the basis of these results, the concentrations of 0.375 and 0.5% ropivacaine held an efficiently analgesic effect for FICB, suggesting that ropivacaine can be employed in analgesic therapy. However, both concentrations have a potentially theoretical risk of local anesthetics poisoning, suggesting that a lower concentration may be a safer option for a single large volume of FICB.

Current Status of Adverse Events Related with Opioid Analgesics in Japan: Assessment Based on Japanese Adverse Drug Event Report Database

Opioid analgesics have greatly contributed to the advancement of pain management. However, although opioids have been appropriately used in Japan, they rarely induce serious adverse events, such as respiratory depression. The present study aimed to investigate the temporal changes in the occurrence of opioid-related adverse events and deaths between 2004 and 2017 in Japan using the Japanese Adverse Drug Event Report (JADER) database. We analyzed the following points using data extracted from JADER website: 1) temporal changes in the number and proportion of opioid-related adverse event reports; 2) temporal changes in the number of morphine-, oxycodone-, and fentanyl-related adverse event reports per annual consumption; and 3) cases in which the reported outcome following opioid-related adverse events was death. Our results showed no dramatic changes in the overall incidence of opioid-related adverse events, despite the temporal changes in the annual consumption and shared component of each opioid during the survey period. However, the number and rate of fentanyl-related adverse events and their outcome "death" increased since 2010, being the highest among all adverse event including those related to morphine and oxycodone. Outcome "death" by fentanyl-related adverse events was caused mainly due to respiratory depression. These findings suggest that, although opioid-related adverse events can be controlled through proper monitoring and management by medical personnel in Japan, extra caution should be continuously paid for the rare but serious fentanyl-induced adverse events.

The epidemiology of prescription fentanyl misuse in the United States

BACKGROUND

US opioid overdose deaths continue to climb, with a 12.0% increase from 2016 to 2017. Fentanyl, a synthetic opioid, has been a major contributor to opioid-related overdose deaths. While fentanyl-related overdose is driven by illicit fentanyl, little is known about individuals who misuse prescription fentanyl, which is also linked to elevated overdose and mortality risk. This work aimed to fill that gap through analyses of prescription fentanyl misuse correlates.

METHODS

Data were from the 2015-16 National Survey on Drug Use and Health (N = 114,043), a nationally representative survey of the non-institutionalized US population. Respondents were (all past-year): those misusing prescription fentanyl (PF); those misusing other (non-fentanyl) prescription opioids (NFPO); and population controls. Respondent groups were compared using multinomial regression on sociodemographics, physical health, mental health and substance use. The PF and NFPO misuse groups were compared on opioid misuse characteristics, using logistic regression.

RESULTS

An estimated 4.4% misused NFPO, and 0.1% misused PF (past-year). Past-year heroin use was more common in those who misused PF (44.3%) than those who misused other NFPO (4.4%; relative risk ratio [RRR] = 7.1, 95%CI = 3.7-13.9) or population controls (0.1%, RRR = 35.1, 95%CI = 17.3-71.1). Non-alcohol substance use disorder (SUD) was similarly elevated in those who misused PF (78.7%) versus the other NFPO group (27.5%, RRR = 3.8, 95%CI = 1.8-8.2) or population controls (1.6%, RRR = 20.6, 95%CI = 9.4-45.5).

CONCLUSIONS

Respondents who misused prescription fentanyl were both more drug-involved generally and opioid-involved specifically; and likely need a combination of significant interventions and monitoring for their polysubstance use.

Risk Factors and Prevention Strategies for Postoperative Opioid Abuse

Worldwide, 80% of patients who undergo surgery receive opioid analgesics as the fundamental agent for pain relief. However, the irrational use of opioids leads to excessive drug dependence and drug abuse, resulting in an increased mortality rate and huge economic loss. The crisis of opioid overuse remains a great challenge. In this review, we summarize several key factors in opioid abuse, including race, region, income, genetic factors, age and gender, smoking and alcohol abuse, history of chronic pain and analgesic drug abuse, surgery, neuropsychiatric illness, depression and antidepressant use, human factors, national policies, hospital regulations, and health insurance under treatment of pain. Furthermore, we present several prevention strategies, such as perioperative measures, opioid substitutes, treatment of the primary illness, emotional regulation, use of opioid antagonists, efforts of the state, hospitals, doctors and pharmacy benefit managers, gene therapy, and vaccines. Greater understanding and better assessment are required of the risks associated with opioid abuse to ensure the safety and analgesic effects of pain treatment after surgery.

Fentanyl and fentanyl-analog involvement in drug-related deaths

BACKGROUND

To describe and analyze the involvement of fentanyl and fentanyl analogs (FAs) in drug-related deaths in West Virginia (WV), United States.

METHODS

Retrospective analyses of all WV drug-related deaths from 2005 to 2017 were performed, including comparisons of demographic and toxicological characteristics among total deaths, deaths in which fentanyl/FAs were present, deaths in which they were absent, heroin-related deaths, and prescription opioid-related deaths.

RESULTS

Most of the 8813 drug-related deaths were overdoses, with about 11% resulting from transportation/other injuries in which drugs were contributors. Prescription opioid presence (without fentanyl) decreased by 75% from 2005-14 to 2015-17 (3545 deaths to 859 deaths, respectively), while fentanyl involvement in the deaths increased by 122% between these periods (487 to 1082 deaths). Ten FAs were identified (427 instances) after 2015. Alprazolam and ethanol were among the top five most frequently identified substances across years. Fentanyl, heroin and cocaine replaced oxycodone, diazepam and hydrocodone in the top five beginning in 2015. Few decedents had a prescription for fentanyl after 2015, with fewer prescriptions also present for other controlled substances identified.

CONCLUSIONS

Fentanyl, rapidly emerging FAs, and other illicit drugs in recent years pose a serious health threat even though prescription opioid-related deaths decreased over the same time period.