Major increases in opioid analgesic abuse in the United States: concerns and strategies

Disease-modifying rdHSV-CA8* non-opioid analgesic gene therapy treats chronic osteoarthritis pain by activating Kv7 voltage-gated potassium channels

Chronic pain is common in our population, and most of these patients are inadequately treated, making the development of safer analgesics a high priority. Knee osteoarthritis (OA) is a primary cause of chronic pain and disability worldwide, and lower extremity OA is a major contributor to loss of quality-adjusted life-years. In this study we tested the hypothesis that a novel JDNI8 replication-defective herpes simplex-1 viral vector (rdHSV) incorporating a modified carbonic anhydrase-8 transgene (CA8*) produces analgesia and treats monoiodoacetate-induced (MIA) chronic knee pain due to OA. We observed transduction of lumbar DRG sensory neurons with these viral constructs (vHCA8*) (~40% of advillin-positive cells and ~ 50% of TrkA-positive cells colocalized with V5-positive cells) using the intra-articular (IA) knee joint (KJ) route of administration. vHCA8* inhibited chronic mechanical OA knee pain induced by MIA was dose- and time-dependent. Mechanical thresholds returned to Baseline by D17 after IA KJ vHCA8* treatment, and exceeded Baseline (analgesia) through D65, whereas negative controls failed to reach Baseline responses. Weight-bearing and automated voluntary wheel running were improved by vHCA8*, but not negative controls. Kv7 voltage-gated potassium channel-specific inhibitor XE-991 reversed vHCA8*-induced analgesia. Using IHC, IA KJ of vHCA8* activated DRG Kv7 channels via dephosphorylation, but negative controls failed to impact Kv7 channels. XE-991 stimulated Kv7.2-7.5 and Kv7.3 phosphorylation using western blotting of differentiated SH-SY5Y cells, which was inhibited by vHCA8* but not by negative controls. The observed prolonged dose-dependent therapeutic effects of IA KJ administration of vHCA8* on MIA-induced chronic KJ pain due to OA is consistent with the specific activation of Kv7 channels in small DRG sensory neurons. Together, these data demonstrate for the first-time local IA KJ administration of vHCA8* produces opioid-independent analgesia in this MIA-induced OA chronic pain model, supporting further therapeutic development.

Discovery of a mu-opioid receptor modulator that in combination with morphinan antagonists induces analgesia

Morphinan antagonists, which block opioid effects at mu-opioid receptors, have been studied for their analgesic potential. Previous studies have suggested that these antagonists elicit analgesia with fewer adverse effects in the presence of the mutant mu-opioid receptor (MOR; S196A). However, introducing a mutant receptor for medical applications represents significant challenges. We hypothesize that binding a chemical compound to the MOR may elicit a comparable effect to the S196A mutation. Through high-throughput screening and structure-activity relationship studies, we identified a modulator, 4-(2-(4-fluorophenyl)-4-oxothiazolidin-3-yl)-3-methylbenzoic acid (BPRMU191), which confers agonistic properties to small-molecule morphinan antagonists, which induce G protein-dependent MOR activation. Co-application of BPRMU191 and morphinan antagonists resulted in MOR-dependent analgesia with diminished side effects, including gastrointestinal dysfunction, antinociceptive tolerance, and physical and psychological dependence. Combining BPRMU191 and morphinan antagonists could serve as a potential therapeutic strategy for severe pain with reduced adverse effects and provide an avenue for studying G protein-coupled receptor modulation.

Investigating neuroepigenetic alterations in chronic low back pain with positron emission tomography

ABSTRACT

Epigenetics has gained considerable interest as potential mediators of molecular alterations that could underlie the prolonged sensitization of nociceptors, neurons, and glia in response to various environmental stimuli. Histone acetylation and deacetylation, key processes in modulating chromatin, influence gene expression; elevated histone acetylation enhances transcriptional activity, whereas decreased acetylation leads to DNA condensation and gene repression. Altered levels of histone deacetylase (HDAC) have been detected in various animal pain models, and HDAC inhibitors have demonstrated analgesic effects in these models, indicating HDACs' involvement in chronic pain pathways. However, animal studies have predominantly examined epigenetic modulation within the spinal cord after pain induction, which may not fully reflect the complexity of chronic pain in humans. Moreover, methodological limitations have previously impeded an in-depth study of epigenetic changes in the human brain. In this study, we employed [11C]Martinostat, an HDAC-selective radiotracer, positron emission tomography to assess HDAC availability in the brains of 23 patients with chronic low back pain (cLBP) and 11 age-matched and sex-matched controls. Our data revealed a significant reduction of [11C]Martinostat binding in several brain regions associated with pain processing in patients with cLBP relative to controls, highlighting the promising potential of targeting HDAC modulation as a therapeutic strategy for cLBP.

rdHSV-CA8 non-opioid analgesic gene therapy decreases somatosensory neuronal excitability by activating Kv7 voltage-gated potassium channels

Chronic pain is common and inadequately treated, making the development of safe and effective analgesics a high priority. Our previous data indicate that carbonic anhydrase-8 (CA8) expression in dorsal root ganglia (DRG) mediates analgesia via inhibition of neuronal ER inositol trisphosphate receptor-1 (ITPR1) via subsequent decrease in ER calcium release and reduction of cytoplasmic free calcium, essential to the regulation of neuronal excitability. This study tested the hypothesis that novel JDNI8 replication-defective herpes simplex-1 viral vectors (rdHSV) carrying a CA8 transgene (vHCA8) reduce primary afferent neuronal excitability. Whole-cell current clamp recordings in small DRG neurons showed that vHCA8 transduction caused prolongation of their afterhyperpolarization (AHP), an essential regulator of neuronal excitability. This AHP prolongation was completely reversed by the specific Kv7 channel inhibitor XE-991. Voltage clamp recordings indicate an effect via Kv7 channels in vHCA8-infected small DRG neurons. These data demonstrate for the first time that vHCA8 produces Kv7 channel activation, which decreases neuronal excitability in nociceptors. This suppression of excitability may translate in vivo as non-opioid dependent behavioral- or clinical analgesia, if proven behaviorally and clinically.

Anti-hyperalgesic and anti-inflammatory effects of 4R-tobacco cembranoid in a mouse model of inflammatory pain

4R is a tobacco cembranoid that binds to and modulates cholinergic receptors and exhibits neuroprotective and anti-inflammatory activity. Given the established function of the cholinergic system in pain and inflammation, we propose that 4R is also analgesic. Here, we tested the hypothesis that systemic 4R treatment decreases pain-related behaviors and peripheral inflammation via modulation of the alpha 7 nicotinic acetylcholine receptors (α7 nAChRs) in a mouse model of inflammatory pain. We elicited inflammation by injecting Complete Freund's Adjuvant (CFA) into the hind paw of male and female mice. We then assessed inflammation-induced hypersensitivity to cold, heat, and tactile stimulation using the Acetone, Hargreaves, and von Frey tests, respectively, before and at different time points (2.5 h - 8d) after a single systemic 4R (or vehicle) administration. We evaluated the contribution of α7 nAChRs 4R-mediated analgesia by pre-treating mice with a selective antagonist of α7 nAChRs followed by 4R (or vehicle) administration prior to behavioral tests. We assessed CFA-induced paw edema and inflammation by measuring paw thickness and quantifying immune cell infiltration in the injected hind paw using hematoxylin and eosin staining. Lastly, we performed immunohistochemical and flow cytometric analyses of paw skin in α7 nAChR-cre::Ai9 mice to measure the expression of α7 nAChRs on immune subsets. Our experiments show that systemic administration of 4R decreases inflammation-induced peripheral hypersensitivity in male and female mice and inflammation-induced paw edema in male but not female mice. Notably, 4R-mediated analgesia and anti-inflammatory effects lasted up to 8d after a single systemic administration on day 1. Pretreatment with an α7 nAChR-selective antagonist prevented 4R-mediated analgesia and anti-inflammatory effects, demonstrating that 4R effects are via modulation of α7 nAChRs. We further show that a subset of immune cells in the hind paw expresses α7 nAChRs. However, the number of α7 nAChR-expressing immune cells is unaltered by CFA or 4R treatment, suggesting that 4R effects are independent of α7 nAChR-expressing immune cells. Together, our findings identify a novel function of the 4R tobacco cembranoid as an analgesic agent in both male and female mice that reduces peripheral inflammation in a sex-dependent manner, further supporting the pharmacological targeting of the cholinergic system for pain treatment.

Adolescent morphine exposure changes the endogenous vlPAG opioid response to inflammatory pain in rats

Adolescence is one of the most critical periods for brain development, and exposure to morphine during this period can have long-life effects on pain-related behaviors. The opioid system in the periaqueductal gray (PAG) is highly vulnerable to drug exposure. However, the impact of adolescent morphine exposure (AME) on the endogenous opioid system in the PAG is currently unknown. This study aims to investigate the long-lasting effects of AME on the endogenous opioid system and its involvement in altering nociceptive behaviors. Adolescent rats were given escalating doses of morphine (2.5-25 mg/kg, subcutaneous) or an equal volume of saline twice daily for 10 consecutive days (PND 31-40). After a 30-day washout period, adult rats underwent formalin tests following microinjection of morphine, naloxone, or saline into the ventrolateral PAG (vlPAG) region. The results indicated that morphine microinjection into the vlPAG of the adolescent morphine-treated group significantly reduced the nociceptive score. However, the analgesic response to morphine in this group was significantly lower compared to the saline-treated group during adolescence. Additionally, the nociceptive score significantly increased following naloxone but not saline microinjection into the vlPAG of the saline-treated group during adolescence, rather than the morphine-treated one. These findings indicate that AME has long-lasting effects on the endogenous opioid system in the vlPAG, which can consequently alter behaviors related to inflammatory pain in adulthood.

Cross state-dependent memory retrieval between tramadol and ethanol: involvement of dorsal hippocampal GABAA receptors

RATIONALE

Tramadol and ethanol, as psychoactive agents, are often abused. Discovering the molecular pathways of drug-induced memory creation may contribute to preventing drug addiction and relapse.

OBJECTIVE

The tramadol- and ethanol-induced state-dependent memory (SDM) and cross-SDM retrieval between tramadol and ethanol were examined in this study. Moreover, because of the confirmed involvement of GABAA receptors and GABAergic neurotransmission in memory retrieval impairment, we assessed cross-SDM retrieval between tramadol and ethanol with a specific emphasis on the role of the GABAA receptors. The first hypothesis of this study was the presence of cross-SDM between tramadol and ethanol, and the second hypothesis was related to possible role of GABAA receptors in memory retrieval impairment within the dorsal hippocampus. The cannulae were inserted into the hippocampal CA1 area of NMRI mice, and a step-down inhibitory avoidance test was used to evaluate state dependence and memory recovery.

RESULTS

The post-training and/or pre-test administration of tramadol (2.5 and 5 mg/kg, i.p.) and/or ethanol (0.5 and 1 g/kg, i.p.) induced amnesia, which was restored after the administration of the drugs 24 h later during the pre-test period, proposing ethanol and tramadol SDM. The pre-test injection of ethanol (0.25 and 0.5 g/kg, i.p.) with tramadol at an ineffective dose (1.25 mg/kg) enhanced tramadol SDM. Moreover, tramadol injection (1.25 and 2.5 mg/kg) with ethanol at the ineffective dose (0.25 g/kg) promoted ethanol SDM. Furthermore, the pre-test intra-CA1 injection of bicuculline (0.0625, 0.125, and 0.25 μg/mouse), a GABAA receptor antagonist, 5 min before the injection of tramadol (5 mg/kg) or ethanol (1 g/kg) inhibited tramadol- and ethanol-induced SDM dose-dependently.

CONCLUSION

The findings strongly confirmed cross-SDM between tramadol and ethanol and the critical role of dorsal hippocampal GABAA receptors in the cross-SDM between tramadol and ethanol.

Is non-medical use normal? Normalisation, medicalisation and pharmaceutical consumption

The theory of the normalisation of youth drug use in advanced capitalist societies has had an enduring legacy in contemporary drug scholarship. While the literature on the normalisation of 'illicit' drugs is well developed, less has been written about application of the theory to emerging discourse of pharmaceutical 'abuse', and how this might necessitate different thinking around what can be considered normal consumption. Pharmaceuticals are not directly associated with criminality, and their use does not traditionally attract stigma. In fact, social science scholarship has illustrated how many substances deemed illicit are normalised in the context of an ever-growing set of medical treatments. This paper explores the assumptions about legality, sociality and pleasure which sit behind the drug normalisation thesis, by reflecting on the relevance of drug normalisation in relation to pharmaceuticals, as well as examining scholarship on the medicalisation of society and qualitative research on non-medical use to illustrate the parallel processes of normalisation that apply to pharmaceuticals. The paper argues that questions of normalisation in relation to pharmaceutical use require a deeper engagement with the normative expectations we attach to pleasure, consumption and medicine, and the way this is structured by proximity to medical authority, whiteness and middle-classness.

Simultaneous application of lidocaine and ketamine during ambulatory infusion therapy: a retrospective analysis

Background: Infusions with lidocaine or ketamine have been separately established in the treatment of chronic pain. This study aims to retrospectively evaluate the effect of combined infusions of lidocaine and ketamine. Materials & methods: Patient records were screened for receipt of combined ambulatory infusions of lidocaine and ketamine from 2012 through 2021. A scoring system was designed to assess pain response retrospectively. Results: A total of 319 patients were included. Median pain reduction in days was 10.00 (interquartile range: 13.25). Side effects were limited to the acute phase of infusions. A total of 41.4% of patients who received concomitant pain medication reported a dose reduction. Conclusion: Our data support combined infusions as a safe therapy option, with good short-, medium- and long-term reductions in pain and great heterogeneity in treatment response. Clinical trial registration: ClinicalTrials.gov (NCT05103319).

Effects of sex and estrous cycle on intravenous oxycodone self-administration and the reinstatement of oxycodone-seeking behavior in rats

Introduction

The increasing misuse of both prescription and illicit opioids has culminated in a national healthcare crisis in the United States. Oxycodone is among the most widely prescribed and misused opioid pain relievers and has been associated with a high risk for transition to compulsive opioid use. Here, we sought to examine potential sex differences and estrous cycle-dependent effects on the reinforcing efficacy of oxycodone, as well as on stress-induced or cue-induced oxycodone-seeking behavior, using intravenous (IV) oxycodone self-administration and reinstatement procedures.

Methods

In experiment 1, adult male and female Long-Evans rats were trained to self-administer 0.03 mg/kg/inf oxycodone according to a fixed-ratio 1 schedule of reinforcement in daily 2-h sessions, and a dose-response function was subsequently determined (0.003-0.03 mg/kg/inf). In experiment 2, a separate group of adult male and female Long-Evans rats were trained to self-administer 0.03 mg/kg/inf oxycodone for 8 sessions, followed by 0.01 mg/kg/inf oxycodone for 10 sessions. Responding was then extinguished, followed by sequential footshock-induced and cue-induced reinstatement tests.

Results

In the dose-response experiment, oxycodone produced a typical inverted U-shape function with 0.01 mg/kg/inf representing the maximally effective dose in both sexes. No sex differences were detected in the reinforcing efficacy of oxycodone. In the second experiment, the reinforcing effects of 0.01-0.03 mg//kg/inf oxycodone were significantly attenuated in females during proestrus/estrus as compared to metestrus/diestrus phases of the estrous cycle. Neither males nor females displayed significant footshock-induced reinstatement of oxycodone seeking, but both sexes exhibited significant cue-induced reinstatement of oxycodone seeking at magnitudes that did not differ either by sex or by estrous cycle phase.

Discussion

These results confirm and extend previous work suggesting that sex does not robustly influence the primary reinforcing effects of oxycodone nor the reinstatement of oxycodone-seeking behavior. However, our findings reveal for the first time that the reinforcing efficacy of IV oxycodone varies across the estrous cycle in female rats.

Post-Acute Care Setting After Hip Fracture Hospitalization and Subsequent Opioid Use in Older Adults

OBJECTIVE

Pain management in post-acute care (PAC) requires careful balance, with both opioid use and inadequate pain treatment linked to poor outcomes. We describe opioid use among older adults following discharge from PAC for hip fracture in skilled nursing facilities (SNFs) and inpatient rehabilitation facilities (IRFs).

DESIGN

Retrospective cohort.

SETTING AND PARTICIPANTS

Medicare beneficiaries with Medicare Provider Analysis (MedPAR) claims, aged 66 years and older with a hip fracture hospitalization between 2012 and 2018 followed by PAC in SNFs or IRFs and then discharge to the community.

METHODS

Individuals were followed from PAC discharge for up to 1 year to assess opioid use. Covariate-standardized risk ratios (RR) and risk differences (RD) for opioid use within 7 days of PAC discharge were estimated via parametric g-formula with modified Poisson regression, and hazard ratios (HRs) for any post-PAC opioid use and long-term opioid use via Fine-Gray sub-distribution hazards regression.

RESULTS

Of 101,021 individuals, 80% (n = 80,495) were discharged from SNFs and 20% (n = 20,526) from IRFs. Opioids were dispensed to 50,433 patients (50%) overall and the 1-year cumulative incidence was notably higher in IRF (68%) than SNF (46%) patients. The adjusted risk of discharge from PAC with an opioid was 41% lower after SNFs versus IRFs [RR: 0.59; 95% confidence limits (CLs): 0.57-0.61; and RD: -0.16; 95% CLs: -0.17 to -0.15]. The adjusted rate of any opioid use in the year after PAC discharge was 44% lower (HR: 0.56; 95% CLs: 0.54-0.57) and of long-term opioid use was 17% lower (HR: 0.83; 95% CLs: 0.80-0.87) after SNFs versus IRFs.

CONCLUSIONS AND IMPLICATIONS

Opioid use is highly prevalent upon discharge from PAC after hip fracture, with lower use after SNF versus IRF care. Future research should assess the benefits and harms of post-PAC opioid prescribing and whether care practices during PAC can be improved to optimize long-term opioid use.

Effects of sex and estrous cycle on intravenous oxycodone self-administration and the reinstatement of oxycodone-seeking behavior in rats

The increasing misuse of both prescription and illicit opioids has culminated in a national healthcare crisis in the United States. Oxycodone is among the most widely prescribed and misused opioid pain relievers and has been associated with a high risk for transition to compulsive opioid use. Here, we sought to examine potential sex differences and estrous cycle-dependent effects on the reinforcing efficacy of oxycodone, as well as on stress-induced or cue-induced oxycodone-seeking behavior, using intravenous (IV) oxycodone self-administration and reinstatement procedures. In experiment 1, adult male and female Long-Evans rats were trained to self-administer 0.03 mg/kg/inf oxycodone according to a fixed-ratio 1 schedule of reinforcement in daily 2-hr sessions, and a dose-response function was subsequently determined (0.003-0.03 mg/kg/inf). In experiment 2, a separate group of adult male and female Long-Evans rats were trained to self-administer 0.03 mg/kg/inf oxycodone for 8 sessions, followed by 0.01 mg/kg/inf oxycodone for 10 sessions. Responding was then extinguished, followed by sequential footshock-induced and cue-induced reinstatement tests. In the dose-response experiment, oxycodone produced a typical inverted U-shape function with 0.01 mg/kg/inf representing the maximally effective dose in both sexes. No sex differences were detected in the reinforcing efficacy of oxycodone. In the second experiment, the reinforcing effects of 0.01-0.03 mg//kg/inf oxycodone were significantly attenuated in females during proestrus/estrus as compared to metestrus/diestrus phases of the estrous cycle. Neither males nor females displayed significant footshock-induced reinstatement of oxycodone seeking, but both sexes exhibited significant cue-induced reinstatement of oxycodone seeking at magnitudes that did not differ either by sex or by estrous cycle phase. These results confirm and extend previous work suggesting that sex does not robustly influence the primary reinforcing effects of oxycodone nor the reinstatement of oxycodone-seeking behavior. However, our findings reveal for the first time that the reinforcing efficacy of IV oxycodone varies across the estrous cycle in female rats.

Perioperative opioids: a narrative review contextualising new avenues to improve prescribing

Opioids have dominated the management of perioperative pain in recent decades with higher doses than ever before used in some circumstances. Through the expanding use of opioids, growing research has highlighted their associated side-effects and the intertwined phenomena of acute withdrawal syndrome, opioid tolerance, and opioid-induced hyperalgesia. With multiple clinical guidelines now endorsing multimodal analgesia, a diverse array of opioid-sparing agents emerges and has been studied to variable degrees, including techniques of opioid-free anaesthesia. It remains unclear to what extent such methods should be adopted, yet current evidence does suggest dependence on opioids as the primary perioperative analgesic might not meet the principles of 'rational prescribing' as described by Maxwell. In this narrative review we describe how, using current evidence, a patient-centred rational-prescribing approach can be applied to opioids in the perioperative period. To contextualise this approach, we discuss the historical adoption of opioids in anaesthesia, our growing understanding of associated side-effects and emerging strategies of opioid-sparing and opioid-free anaesthesia. We discuss avenues and challenges for improving opioid prescribing to limit persistent postoperative opioid use and how these may be incorporated into a rational-prescribing approach.

Adolescent morphine exposure impairs dark avoidance memory and synaptic potentiation of ventral hippocampal CA1 during adulthood in rats

Adolescence is a neurobiological critical period for neurodevelopmental processes. Adolescent opioid exposure can affect cognitive abilities via regional-specific lasting changes in brain structure and function. The current study was therefore designed to assess the long-term effects of adolescent morphine exposure on dark avoidance memory and synaptic plasticity of the ventral hippocampal CA1. Adolescent Wistar rats received escalating doses of morphine for 10 days. Morphine injections were started with an incremental dose of 2.5 mg/kg to reach a dose of 25 mg/kg. 30 days after the last injection, inhibitory memory and in vitro field potential recording were evaluated. Also, the weight of the animals was measured during drug and post-drug exposure. We found that adolescent morphine exposure decreased weight gain during morphine and post-morphine exposure. Passive avoidance memory was impaired in the morphine group. Moreover, adolescent morphine exposure caused an increase in baseline synaptic responsiveness and failed long-term potentiation (LTP) in the ventral hippocampal CA1 during adulthood. In the morphine group, the mean values of the field excitatory postsynaptic potential (fEPSP) slopes required to elicit a half-maximal population spike (PS) amplitude were significantly greater than that of the saline group. Therefore, adolescent morphine exposure has a durable effect on memory functions, synaptic activity, and plasticity of ventral hippocampal CA1. Adults with adolescent morphine exposures may experience maladaptive behaviors and cognitive disabilities.

A comparison of clinical characteristics of psychiatric inpatients in three hospitals from Western China and America

BACKGROUND

Different countries have differences in social and cultural context and health system, which may affect the clinical characteristics of psychiatric inpatients. This study was the first to compare cross-cultural differences in the clinical characteristics of psychiatric inpatients in three hospitals from Western China and America.

METHODS

Overall, 905 and 1318 patients from three hospitals, one in America and two in Western China, respectively, were included. We used a standardised protocol and data collection procedure to record inpatients' sociodemographic and clinical characteristics.

RESULTS

Significant differences were found between hospitals from the two countries. Positive symptoms were the main reason for admission in the Chinese hospitals, while reported suicide and self-injury symptoms more frequently led to hospital admission in America. Moreover, there were more inpatients with combined substance abuse in the American hospital (97.6% vs. 1.9%, P < 0.001). The length of stay (LOS) in America was generally shorter than in China (10.5 ± 11.9 vs. 20.7 ± 13.4, P < 0.001). The dosage of antipsychotic drugs used in the American hospital was higher than in China (275.1 ± 306.9 mg vs. 238.3 ± 212.5 mg, P = 0.002). Regression analysis showed that male sex, older age, retirees, being admitted because of physical symptoms, and using higher doses of antipsychotic drugs were significantly associated with longer hospitalisation in the American hospital (P < 0.05). Comparatively, patients who were divorced, experiencing suicidal ideation, admitted involuntarily, admitted because of physical, depression, or anxiety symptoms, and using higher doses of antipsychotic drugs had longer hospitalisation in Chinese hospitals (P < 0.05).

CONCLUSION

Significant variations in clinical characteristics of inpatients were found between hospitals from Western China and America. The LOS in Chinese hospitals was significantly longer, but patients used higher doses of antipsychotic drugs in the American hospital. Admission due to physical symptoms and the use of higher dosage drugs were related to longer LOS in both countries.

Testing the Decision Support Tool for Responsible Pain Management for Headache and Facial Pain Diagnosis with Opioid-Risk-Stratified Treatment

In primary and urgent care, headache and facial pain are common and challenging to diagnose and manage, especially with using opioids appropriately. We therefore developed the Decision Support Tool for Responsible Pain Management (DS-RPM) to assist healthcare providers in diagnosis (including multiple simultaneous diagnoses), workup (including triage), and opioid-risk-informed treatment. A primary goal was to supply sufficient explanations of DS-RPM's functions allowing critique. We describe the process of iteratively designing DS-RPM adding clinical content and testing/defect discovery. We tested DS-RPM remotely with 21 clinician-participants using three vignettes-cluster headache, migraine, and temporal arteritis-after first training to use DS-RPM with a trigeminal-neuralgia vignette. Their evaluation was both quantitative (usability/acceptability) and qualitative using semi-structured interviews. The quantitative evaluation used 12 Likert-type questions on a 1-5 scale, where 5 represented the highest rating. The mean ratings ranged from 4.48 to 4.95 (SDs ranging 0.22-1.03). Participants initially found structured data entry intimidating but adapted and appreciated its comprehensiveness and speed of data capture. They perceived DS-RPM as useful for teaching and clinical practice, making several enhancement suggestions. The DS-RPM was designed, created, and tested to facilitate best practice in management of patients with headaches and facial pain. Testing the DS-RPM with vignettes showed strong functionality and high usability/acceptability ratings from healthcare providers. Risk stratifying for opioid use disorder to develop a treatment plan for headache and facial pain is possible using vignettes. During testing, we considered the need to adapt usability/acceptability evaluation tools for clinical decision support, and future directions.

Investigating the potential of mirtazapine to induce drug-seeking behavior in free-choice drinking mouse model

Addiction to various drugs and chemicals is a significant public health concern worldwide. Addiction to prescription medications has increased due to the psychoactive effects of these medications, their availability, low price, and the lack of legal consequences for abusers. One of such prescription medication is mirtazapine (MIRT). MIRT is an antidepressant that has recently been reported to be abused and could induce withdrawal symptoms in different case studies. No previous study has investigated its abuse potential in animal models of drug addiction. Here, we conducted a free-choice drinking paradigm to investigate voluntary drinking of MIRT at two different concentrations. Male BALB/c mice were given unlimited access to two water bottles for five days before being divided into three groups: the first group had free access to two water bottles. The second group (MIRT10) and the third group (MIRT20) was allowed unlimited choice to one bottle of water and one bottle of MIRT at concentrations of 0.03 and 0.06 mg/mL, respectively. The average daily MIRT intake in the MIRT20 group was significantly higher on all tested days than that in the MIRT10 group. Moreover, mice in the MIRT20 group preferred to self-administer MIRT over water, indicating that MIRT can induce drug-seeking behavior. To further investigate the addictive potential of MIRT and its possible deterioration of memory and recognition, as reported with several known drugs of abuse, animals underwent a novel object recognition test. Mice in the MIRT20 group demonstrated significant deterioration in memory and recognition, indicating its effects on different brain regions involved in recognition, similar to other known drugs of abuse. The forced swimming test and tail suspension test were used to test MIRT-induced withdrawal symptoms after forced abstinence. After eight days of abstinence, mice in the MIRT20 group demonstrated significant depression-like symptoms in both the TST and FST, manifested by a significant increase in immobility time. MIRT was shown to induce drug-seeking behavior, deteriorate recognition, and cause withdrawal symptoms. This might confirm that MIRT has the potential to induce drug dependence and further studies are warranted to explore the neurobiological basis of MIRT-induced drug-seeking behavior.

Development of anxiety-like behaviors during adolescence: Persistent effects of adolescent morphine exposure in male rats

Epidemiological studies show the prevalence of opioid use, misuse and abuse in adolescents, which imposes social and economic accountability worldwide. Chronic opioid exposure, especially in adolescents, may have lasting effects on emotional behaviors that persist into adulthood. The current experiments were therefore designed to study the effects of sustained opioid exposure during adolescence on anxiety-like behaviors. Adolescent male Wistar rats underwent increasing doses of morphine for 10 days (PNDs 31-40). After that the open field test (OFT) and elevated plus maze (EPM) test were performed over a 4-week postmorphine treatment from adolescence to adulthood. Moreover, the weight of the animals was measured at these time points. We found that chronic adolescent morphine exposure reduces the weight gain during the period of morphine treatment and 4 weeks after that. It had no significant effect on the locomotor activity in the animals. Moreover, anxiolytic-like behavior was observed in the rats exposed to morphine during adolescence evaluated by OFT and EPM test. Thus, long-term exposure to morphine during adolescence has the profound potential of altering the anxiety-like behavior profile in the period from adolescence to adulthood. The maturation of the nervous system can be affected by drug abuse during the developmental window of adolescence and these effects may lead to behaviorally stable alterations.

Endogenous opioid systems alterations in pain and opioid use disorder

Decades of research advances have established a central role for endogenous opioid systems in regulating reward processing, mood, motivation, learning and memory, gastrointestinal function, and pain relief. Endogenous opioid systems are present ubiquitously throughout the central and peripheral nervous system. They are composed of four families, namely the μ (MOPR), κ (KOPR), δ (DOPR), and nociceptin/orphanin FQ (NOPR) opioid receptors systems. These receptors signal through the action of their endogenous opioid peptides β-endorphins, dynorphins, enkephalins, and nociceptins, respectfully, to maintain homeostasis under normal physiological states. Due to their prominent role in pain regulation, exogenous opioids-primarily targeting the MOPR, have been historically used in medicine as analgesics, but their ability to produce euphoric effects also present high risks for abuse. The ability of pain and opioid use to perturb endogenous opioid system function, particularly within the central nervous system, may increase the likelihood of developing opioid use disorder (OUD). Today, the opioid crisis represents a major social, economic, and public health concern. In this review, we summarize the current state of the literature on the function, expression, pharmacology, and regulation of endogenous opioid systems in pain. Additionally, we discuss the adaptations in the endogenous opioid systems upon use of exogenous opioids which contribute to the development of OUD. Finally, we describe the intricate relationship between pain, endogenous opioid systems, and the proclivity for opioid misuse, as well as potential advances in generating safer and more efficient pain therapies.

Ketamine for acute pain after trauma: the KAPT randomized controlled trial

Background

Evidence for effective pain management and opioid minimization of intravenous ketamine in elective surgery has been extrapolated to acutely injured patients, despite limited supporting evidence in this population. This trial seeks to determine the effectiveness of the addition of sub-dissociative ketamine to a pill-based, opioid-minimizing multi-modal pain regimen (MMPR) for post traumatic pain.

Methods

This is a single-center, parallel-group, randomized, controlled comparative effectiveness trial comparing a MMPR to a MMPR plus a sub-dissociative ketamine infusion. All trauma patients 16 years and older admitted following a trauma which require intermediate (IMU) or intensive care unit (ICU) level of care are eligible. Prisoners, patients who are pregnant, patients not expected to survive, and those with contraindications to ketamine are excluded from this study. The primary outcome is opioid use, measured by morphine milligram equivalents (MME) per patient per day (MME/patient/day). The secondary outcomes include total MME, pain scores, morbidity, lengths of stay, opioid prescriptions at discharge, and patient centered outcomes at discharge and 6 months.

Discussion

This trial will determine the effectiveness of sub-dissociative ketamine infusion as part of a MMPR in reducing in-hospital opioid exposure in adult trauma patients. Furthermore, it will inform decisions regarding acute pain strategies on patient centered outcomes.

Trial registration

The Ketamine for Acute Pain Management After Trauma (KAPT) with registration # NCT04129086 was registered on October 16, 2019.

The association of prescription opioid use with suicide attempts: An analysis of statewide medical claims data

Background

Suicides and opioid overdose deaths are among the most pressing public health concerns in the US. However direct evidence for the association between opioid use and suicidal behavior is limited. The objective of this article is to examine the association between frequency and dose of prescription opioid use and subsequent suicide attempts.

Methods and findings

This retrospective cohort study analyzed 4 years of statewide medical claims data from the Connecticut All-Payer Claims Database. Commercially insured adult patients in Connecticut (n = 842,773) who had any medical claims beginning in January 2012 were followed through December 2015. The primary outcome was suicide attempt identified using International Classification of Diseases (ICD 9) diagnosis codes. Primary predictor variables included frequency of opioid use, which was defined as the number of months with claims for prescription opioids per year, and strength of opioid dose, which was standardized using morphine milligram equivalent (MME) units. We also controlled for psychiatric and medical comorbidities using ICD 9 codes. We used Cox proportional hazards regression to examine the association between frequency, dose, and suicide attempts, adjusting for medical and psychiatric comorbid conditions. Interactions among measures of opioid use and comorbid conditions were analyzed.

In this cohort study with follow-up time up to 4 years (range = 2–48 months, median = 46 months), the hazard ratios (HR) from the time-to-event analysis indicated that patients prescribed opioid medications for at least 6 months during the past year and at 20–50 MME levels or higher had 4.44 (95% CI: [3.71, 5.32]) to 7.23 (95% CI: [6.22, 8.41]) times the risk of attempted suicide compared to those not prescribed opioids. Risk of suicide attempt was sharply elevated among patients with psychiatric conditions other than anxiety who were prescribed more frequent and higher opioid doses. In contrast, more frequent and higher doses of prescription opioids were associated with lower risk of suicide attempts among patients with medical conditions necessitating pain management.

This study is limited by its exclusive focus on commercially insured patients and does not include patients covered by public insurance. It is also limited to patients’ receipt of prescription opioids and does not take into account opioids obtained through other means, nor does it include measures of actual patient opioid use.

Conclusions

This analysis provides evidence of a complex relationship among prescription opioids, mental health, pain and other medical comorbidities, and suicide risk. Findings indicate the need for proactive suicide surveillance among individuals diagnosed with affective or psychotic disorders who are receiving frequent and high doses of opioids. However, appropriate opioid treatment may have significant value in reducing suicide risk for those without psychiatric comorbidities.

Pain and suicide: what should we tell our trainees?

Chronic pain is a debilitating medical condition affecting a significant percentage of the population worldwide. Considerable evidence suggests that pain is an independent risk factor for suicide and inadequately managing pain has been identified as a risk for suicidal behaviour. Additionally, medications used to treat pain may also contribute to suicidal behaviour. Extensive research on pain highlights deficiencies in the clinical management on pain with more gaps in care when patients have pain in combination with mental illness and suicidal behaviour. Providing trainees additional knowledge and equipping them with relevant tools to screen and manage chronic pain efficiently is a potential strategy to mitigate suicide risk. Also, trainees need to be educated on how to screen for suicidality in individuals with pain and apply suicide prevention interventions. This paper will emphasise the necessity to improve education about pain, its close relationship with suicide and effective suicide screening as well as management strategies for medical providers. With additional research, it is the hope that novel treatment modalities will be developed to treat pain to improve the quality of life of individuals suffering from this condition and to decrease suicide risk in this patient population.

Leveraging the Prescription Drug Monitoring Program to Curb Opioid Prescribing in Arkansas

Effective means of accurately identifying problematic opioid prescribing are needed. Using an iterative approach with the Arkansas State Medical Board Pain Subcommittee, we modified existing opioid prescriber criteria to create seven metrics to be deployed in Arkansas. These included metrics of dose and days' supply, concomitant use of opioid and benzodiazepines, solid dosage units, and numbers of opioid patients and certain opioid prescriptions. Two of these metrics (average MME daily dose per prescription and total oxycodone 30 mg or hydromorphone prescriptions) were weighted by 2, creating a maximum score of 9 of which each prescriber could receive. Twenty prescribers with a score of 7 or greater were identified and referred to the Arkansas State Medical Board Pain Subcommittee for review and subsequent investigation if deemed necessary. Of those 20 prescribers, four were previously investigated and under disciplinary action, and three were under current investigation for misconduct related to prescribing practices. Five prescribers had new investigations opened due to the findings from the metrics, and disciplinary action was taken. Therefore, 12 of the 20 prescribers referred to the Arkansas State Medical Board were deemed worthy of investigation and disciplinary action. The Arkansas opioid prescriber metrics are able to accurately identify prescribers with potentially problematic opioid prescribing.

'Adequacy between medical prescription and intake of analgesics for acute low back and neck pain after presentation at the emergency department - do we prescribe too many tablets?'

OBJECTIVES

Acute low back and neck pain account for 3% to 6% of emergency room consultations. In Europe, analgesic prescriptions are issued in boxes. This study, therefore, aims to assess whether this type of packaging is adapted to the real needs of patients.

METHODS

This is a prospective observational multicenter study. Out of a total of 101 eligible patients who consulted the emergency department with acute low back or neck pain of muscular origin, 60 patients were included for statistical analysis. Follow-up was conducted by phone 10 to 14 days after admission. Different parameters were evaluated: the recovery, the amount of remaining tablets, and the demographic characteristics of patients.

RESULTS

Seventy-five percent of the evaluated patients were asymptomatic at follow-up and no longer taking the prescribed treatment. For all types of prescribed analgesics, a significant number of tablets remained in the drug boxes (P < 0.0001). After the resolution of symptoms, 90% of the studied patients reported a drug surplus. No significant difference was found in terms of patient demographic characteristics. The results were similar for both neck and low back pain subgroups.

CONCLUSION

This study suggests that in case of acute low back and neck pain, a significant number of patients who return home after an emergency department consultation have a surplus of analgesics after recovery. These drugs could induce misuse. Moreover, this surplus gives rise to economic and environmental questions. One solution could be to prescribe a number of tablets depending on patients' pathology instead of entire boxes.

Parallel Spinal Pathways for Transmitting Reflexive and Affective Dimensions of Nocifensive Behaviors Evoked by Selective Activation of the Mas-Related G Protein-Coupled Receptor D-Positive and Transient Receptor Potential Vanilloid 1-Positive Subsets of Nociceptors

The high incidence of treatment-resistant pain calls for the urgent preclinical translation of new analgesics. Understanding the behavioral readout of pain in animals is crucial for efficacy evaluation when developing novel analgesics. Mas-related G protein-coupled receptor D-positive (Mrgprd⁺) and transient receptor potential vanilloid 1-positive (TRPV1⁺) sensory neurons are two major non-overlapping subpopulations of C-fiber nociceptors. Their activation has been reported to provoke diverse nocifensive behaviors. However, what kind of behavior reliably represents subjectively conscious pain perception needs to be revisited. Here, we generated transgenic mice in which Mrgprd⁺ or TRPV1⁺ sensory neurons specifically express channelrhodopsin-2 (ChR2). Under physiological conditions, optogenetic activation of hindpaw Mrgprd⁺ afferents evoked reflexive behaviors (lifting, etc.), but failed to produce aversion. In contrast, TRPV1⁺ afferents activation evoked marked reflexive behaviors and affective responses (licking, etc.), as well as robust aversion. Under neuropathic pain conditions induced by spared nerve injury (SNI), affective behaviors and avoidance can be elicited by Mrgprd⁺ afferents excitation. Mechanistically, spinal cord-lateral parabrachial nucleus (lPBN) projecting neurons in superficial layers (lamina I–II_o) were activated by TRPV1⁺ nociceptors in naïve conditions or by Mrgprd⁺ nociceptors after SNI, whereas only deep spinal cord neurons were activated by Mrgprd⁺ nociceptors in naïve conditions. Moreover, the excitatory inputs from Mrgprd⁺ afferents to neurons within inner lamina II (II_i) are partially gated under normal conditions. Altogether, we conclude that optogenetic activation of the adult Mrgprd⁺ nociceptors drives non-pain-like reflexive behaviors via the deep spinal cord pathway under physiological conditions and drives pain-like affective behaviors via superficial spinal cord pathway under pathological conditions. The distinct spinal pathway transmitting different forms of nocifensive behaviors provides different therapeutic targets. Moreover, this study appeals to the rational evaluation of preclinical analgesic efficacy by using comprehensive and suitable behavioral assays, as well as by assessing neural activity in the two distinct pathways.

Dispensed Opioid Prescription Patterns, by Racial/Ethnic Groups, Among South Carolina Medicaid-Funded Children Experiencing Limb Fracture Injuries

OBJECTIVE

To examine dispensed opioid prescription patterns for limb fractures across racial/ethnic groups in a pediatric population.

METHODS

We used South Carolina's Medicaid claims data 2000 to 2018 for pediatric limb fracture cases (under age 19) discharged from the emergency department. The key independent variable was the child's race/ethnicity. The outcomes were: 1) whether the patient had a dispensed opioid prescription; and 2) whether dispensed opioid supply was longer than 5 days among cases with any dispensed opioid prescriptions. Logistic regression models were used to test the association between race/ethnicity and the outcomes. Covariates included age-at-service, gender, service year, and having multiple fracture injuries.

RESULTS

Compared with non-Hispanic White cases (NHW), the odds of receiving dispensed opioid prescriptions were lower for cases of non-Hispanic Black (NHB) (OR = 0.73; 95% confidence interval [CI]: 0.71, 0.75), Asian (OR = 0.69; CI: 0.53, 0.90), Other/Unknown (OR = 0.86; CI: 0.80, 0.92), and Hispanic (OR = 0.84; CI: 0.79, 0.90) race/ethnicity. The odds of receiving >5 days of dispensed opioid prescription supply did not differ significantly among race/ethnic categories.

CONCLUSIONS

Our study confirms previous findings that as compared to NHW, the NHB children were less likely to receive dispensed opioid prescriptions. Also, it reveals that the different minority race/ethnic groups are not homogenous in their likelihoods of receiving dispensed opioid prescriptions after a limb fracture compared to NHW, findings underreported in previous studies. Children in the Other/Unknown race/ethnicity category have prescribing patterns different from those of other minority race/ethnic groups and should be analyzed separately.

Longitudinal Analysis of Substance Use Disorder Symptom Severity at Age 18 Years and Substance Use Disorder in Adulthood

IMPORTANCE

Although more than 1 in every 3 US individuals will develop a substance use disorder (SUD) in their lifetime, relatively little is known about the long-term sequelae of SUD symptoms from adolescence through adulthood.

OBJECTIVE

To evaluate the longitudinal associations between adolescents' SUD symptom severity with later medical use of prescription drugs (ie, opioids, sedatives, and tranquilizers), prescription drug misuse (PDM), and SUD symptoms at ages 35 to 50 years.

DESIGN, SETTING, AND PARTICIPANTS

Eleven cohorts of US 12th grade students were followed longitudinally from age 18 years (1976-1986) to age 50 years (2008-2018) in the Monitoring the Future (MTF) study. Baseline surveys were self-administered in classrooms, and follow-ups were conducted by mail. Data were analyzed from June 2021 to February 2022.

EXPOSURE

Response to MTF study between 1976 and 2018.

MAIN OUTCOMES AND MEASURES

Sociodemographic variables were measured at baseline. All bivariate and multivariate analyses use attrition weights to adjust for attrition by age 50 years within the sample. SUD symptoms, prescription drug use, and PDM were measured at baseline and every follow-up.

RESULTS

The sample of 5317 individuals was 51.2% female (2685 participants; 95% CI, 49.6%-52.6%) and 77.9% White (4222 participants; 95% CI, 77.6%-79.1%). Participants were surveyed beginning at age 18 years and ending at age 50 years. The baseline response rate ranged from 77% to 84%, and the 32-year retention rate was 53%. Most adolescents with most severe SUD symptoms at age 18 years had 2 or more SUD symptoms in adulthood (316 participants [61.6%]; 95% CI, 55.7%-66.9%), and this association held for baseline alcohol, cannabis, and other drug use disorder symptoms. Adolescents with the highest SUD symptom severity at age 18 years had the highest adjusted odds of prescription drug use and PDM in adulthood (4-5 symptoms, adjusted odds ratio, 1.56; 95% CI, 1.06-2.32; ≥6 symptoms, adjusted odds ratio, 1.55; 95% CI, 1.11-2.16). The majority of adults using prescribed opioids, sedatives, or tranquilizers (568 participants [52.2%]; 95% CI, 48.4%-55.9%) in the past year had multiple SUD symptoms at age 18 years.

CONCLUSIONS AND RELEVANCE

These findings suggest that most adolescents with severe SUD symptoms do not transition out of symptomatic substance use, and the long-term sequelae for adolescents with more severe SUD symptoms are more deleterious than those for adolescents with no or low severity. Prescribers should be aware that many adults prescribed opioids, sedatives, or tranquilizers had multiple SUD symptoms during adolescence and require careful assessment and monitoring.

Effects of County-Level Opioid Dispensing Rates on Individual-Level Patterns of Prescription Opioid and Heroin Consumption: Evidence From National U.S. Data

OBJECTIVE

The authors examined directly whether county-level changes in opioid dispensing rates affect individual-level prescription opioid misuse, frequency of use, and dependence, as well as the same outcomes for heroin.

METHODS

Using data from the restricted-access National Survey on Drug Use and Health, the Centers for Disease Control and Prevention's retail opioid prescription database, the Prescription Drug Abuse Policy System, and the U.S. Census, the authors applied fixed-effects models to determine whether county-level dispensing rates affected prescription opioid outcomes as intended and whether changes in rates adversely affected heroin use outcomes. Bayes factors were used to confirm evidence for null findings.

RESULTS

The sample included 748,800 respondents age 12 and older from 2006 to 2016. The odds of prescription opioid misuse, increased frequency of misuse, and dependence were 7.2%, 3.5%, and 10.4% higher, respectively, per standard deviation increase in the county-level opioid dispensing rate per 100 persons. There was no evidence for any association between opioid dispensing rates and the three heroin outcomes. The odds ratio was nonsignificant according to frequentist techniques in fixed-effects models, and Bayesian techniques confirmed very strong support for the null hypothesis.

CONCLUSIONS

County-level opioid dispensing rates are directly associated with individual-level prescription opioid misuse, frequency of misuse, and dependence. Changes in dispensing were not associated with population shifts in heroin use. Reductions in opioid dispensing rates have contributed to stemming prior increases in prescription opioid misuse while not adversely affecting heroin use. Physicians and other health care providers can take action to minimize opioid dispensing for tangible benefits regarding prescription opioid misuse without adverse effects on heroin use.

Later-life transitions and changes in prescription medication use for pain and depression

Background

Over the past two decades, prescription medication use for pain and depression increased dramatically. Most studies consider the early life course, despite a similar increase among those in later life. In this paper, we examine whether and how later life transitions may relate to changes in medication use.

Methods

We draw on data from the Health and Retirement Study and fixed-effects models to examine whether work, family, and civic transitions in later life are related to changes in the usage of prescription pain and depression medication.

Results

Results show that individuals had higher odds of regularly using prescription pain and depression medications in periods when out of the labor market. Higher odds of depression medication use were also associated with periods of widowhood, and lower odds of use when frequently volunteering. Such relations persist adjusting for reported levels of pain and depression.

Conclusion

Our findings call attention to the importance of social ties and the presence of actors that may regulate health behaviors, as well as a change in social context, that may shape medication use in later life.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-02921-y.

Effectiveness of online training of first and second year AEGD residents in identifying, referring, and managing patients at-risk for substance use and opioid disorders

BACKGROUND AND OBJECTIVES

Dentists have contributed greatly to the opioid epidemic, dispensing roughly 8.6% of opioids totaling over 18 million prescriptions in a 12-month period from July 2016 to June 2017 and report educational gaps regarding screening techniques for substance misuse and an unfamiliarity with available referral resources. The purpose of this study was to determine the knowledge and comfort level of residents in identifying, referring, and managing patients who are at risk for opioid use or substance use disorder in the dental setting before and after an online case-based training course.

METHODS

Thirty-five first year (PGY1) and 11 second year (PGY2) advanced education in general dentistry (AEGD) residents participated in an online training course that aimed to assess knowledge in the domains of identifying, referring, and managing patients at risk for substance abuse disorder and opioid use in an academic setting. There were nine subdomains within the three major domains that further assessed resident comfort and knowledge. Before and after training, data were collected and analyzed.

RESULTS

Analysis of the results indicated that (1) the training modules increased resident comfort in identifying (p = 0.011), referring (p = 0.032), and managing (p = 0.002) patients at risk for opioid substance use. (2) PGY1 residents benefited more than PGY2 residents in identifying (p = 0.034) and the manage domains (p < 0.001). (3) Residents viewed the module quality, usefulness, and applicability favorably. Further analysis of the nine subdomains is presented.

CONCLUSION

Our study suggests that dental curricula would benefit from incorporating training of residents in identifying, referring, and managing patients at risk for substance use disorder and opioid use.

Sex Differences in Kappa Opioid Receptor Agonist Mediated Attenuation of Chemotherapy-Induced Neuropathic Pain in Mice

Chemotherapy-induced neuropathic pain is a common side effect for cancer patients which has limited effective treatment options. Kappa opioid receptor (KOR) agonists are a promising alternative to currently available opioid drugs due to their low abuse potential. In the current study, we have investigated the effects of Salvinorin A (SalA) analogues, 16-Ethynyl SalA, 16-Bromo SalA and ethyoxymethyl ether (EOM) SalB, and in a preclinical model of paclitaxel-induced neuropathic pain in male and female C57BL/6J mice. Using an acute dose-response procedure, we showed that compared to morphine, 16-Ethynyl SalA was more potent at reducing mechanical allodynia; and SalA, 16-Ethynyl SalA, and EOM SalB were more potent at reducing cold allodynia. In the mechanical allodynia testing, U50,488 was more potent in males and SalA was more potent in females. There were no sex differences in the acute cold allodynia testing. In the chronic administration model, treatment with U50,488 (10 mg/kg) reduced the mechanical and cold allodynia responses to healthy levels over 23 days of treatment. Overall, we have shown that KOR agonists are effective in a model of chemotherapy-induced neuropathic pain, indicating that KOR agonists could be further developed to treat this debilitating condition.

Pain and Pain Control With Opioid and Nonopioid Medications After Otologic Surgery

OBJECTIVE

To prospectively analyze pain and pain medication use following otologic surgery.

STUDY DESIGN

Prospective cohort study with patient reported pain logs and medication use logs.

SETTING

Tertiary academic hospital.Patients: Sixty adults who underwent outpatient otologic surgeries.

INTERVENTIONS

Surveys detailing postoperative pain levels, nonopioid analgesic (NOA) use, and opioid analgesic use.

MAIN OUTCOME MEASURES

Self-reported pain scores, use of NOA, and use of opioid medications normalized as milligrams morphine equivalents (MME).

RESULTS

Thirty-two patients had surgery via a transcanal (TC) approach, and 28 patients had surgery via a postauricular (PA) approach. TC surgery had significantly lower reported pain scores than PA surgery on both postoperative day (POD) 1 (median pain score 2.2, IQR 0-5 vs. median pain score 4.8, IQR 3.4-6.3, respectively; p = 0.0013) and at POD5 (median pain score 0, IQR 0-0 vs. median pain score 2.0, IQR 0-3, respectively; p = 0.0002). Patients also used significantly fewer opioid medications with TC approach than patients who underwent PA approach at POD1 (median total MME 0, IQR 0-5 vs. median total MME 5.0, IQR 0-15, respectively; p = 0.03) and at POD5 (median total MME 0, IQR 0-0 vs. median total MME 0, IQR 0-5, respectively; p = 0.0012).

CONCLUSIONS

Surgery with a postauricular approach is associated with higher pain and opioid use following otologic surgery. Patient- and approach-specific opioid prescribing is feasible following otologic surgery.

Slow-sustained delivery of naloxone reduces typical naloxone-induced precipitated opioid withdrawal effects in male morphine-dependent mice

Thousands of individuals die each year from opioid-related overdoses. While naloxone (Narcan®) is currently the most widely employed treatment to reverse opioid toxicity, high or repeated doses of this antidote often lead to precipitated opioid withdrawal (POW). We hypothesized that a slow linear release of naloxone from a nanoparticle would induce fewer POW symptoms compared to high-dose free naloxone. First, we measured the acute impact of covalent naloxone nanoparticles (Nal-cNPs) on morphine-induced antinociception in the hotplate test. We found that Nal-cNP treatment blocked the antinociceptive effect of morphine within 15 min of administration. Next, we tested the impact of Nal-cNPs on POW symptoms in male morphine-dependent mice. To induce morphine dependence, mice were treated with 5 mg/kg morphine (or saline) twice-daily for six consecutive days. On day 7 mice received 5 mg/kg morphine (or saline) injections 2 hr prior to receiving treatment of either unmodified free naloxone, a high or low dose of Nal-cNP, empty nanoparticle (cNP-empty), or saline. Behavior was analyzed for 0-6 hr followed by 24 and 48 hr time points after treatment. As expected, free naloxone induced a significant increase in POW behavior in morphine-dependent mice compared to saline-treated mice upon free naloxone administration. In comparison, reduced POW behavior was observed with both doses of Nal-cNP. Side effects of Nal-cNP on locomotion and fecal boli production were measured and no significant side-effects were observed. Overall, our data show that sustained release of naloxone from a covalent nanoparticle does not induce severe POW symptoms in morphine-dependent mice.

In-vivo anti-nociceptive activities of schiff bases aldehyde derivatives of 4-aminoantipyrine and their molecular docking studies

In this study, the anti-nociceptive potential of Schiff bases derivatives of 4-aminoantioyrine, (Z)-4-(4-hydroxy-3-methoxybenzylideneamino)-2, 3-dimethyl-1-phenyl-1, 2dihydropyrazol-5-one 1 and (Z)-4-(2-nitrobenzylideneamino)-2, 3-dimethyl-1-phenyl-1-2-dihydropyrazol-5-one 2 were tested in various mice pain models and their binding affinities with different drug targets were evaluated through molecular docking studies. The binding scores were calculated through molecular docking techniques for receptor sensitivity. Acute toxicity test suggests the safety of both compounds up 200 mg/kg. In the righting test, compound 1 and 2 had a significant effect in a dose-dependent manner and showed 59.46% and 48.40% blockade of pain at 150 mg/kg, respectively. In the formalin test, dose-dependently compound 1 showed 52.95% and 62.02% of inhibition in the early and late phase at 150 mg/kg. Similarly, Compound 2 showed 45.74% and 55.95% inhibition in the early and late phases at 150 mg/kg, respectively. In the tail immersion test, both compounds caused significant pain inhibition during various assessment times with maximum effects at 74.94% and 66.80% for 1 and 2 respectively at 150 mg/kg after 120 min. In molecular docking studies, compounds 1 and 2 showed a greater affinity for LOX with a docking score of –6.50 and 6.57 respectively. Similarly, for compounds 1 and 2 the docking was –4.94 and –4.83 with COX-1 while –5.10 and –4.85 with COX-2, respectively. Taken together, both the compounds exhibited marked antinociceptive effects in various pain-induced models possibly mediated by inhibition of LOX and COX pathways.

Effectiveness of Oxycodone Hydrochloride (Strong Opioid) vs Combination Acetaminophen and Codeine (Mild Opioid) for Subacute Pain After Fractures Managed Surgically: A Randomized Clinical Trial

IMPORTANCE

Patients with a surgically managed fracture are commonly discharged from the hospital with a strong opioid prescription, but limited evidence exists to support this practice.

OBJECTIVE

To test the hypothesis that strong opioids provide greater analgesia than mild opioids over the first week postdischarge from hospital after fracture surgical treatment.

DESIGN, SETTING, AND PARTICIPANTS

This double-blind, superiority, randomized clinical trial was conducted at a single-center, major trauma hospital in Sydney, Australia. Participants were inpatients who had sustained an acute nonpathological facture of a long bone or the pelvis, patella, calcaneus, or talus who were treated with surgical fixation and enrolled from July 27, 2016, to August 22, 2017. Data were analyzed from June through October 2018.

INTERVENTIONS

Initiation at discharge of oxycodone hydrochloride 5 mg of 10 mg (ie, 1 or 2 tablets) or combination acetaminophen and codeine 500 mg and 8 mg or 1000 mg and 16 mg (ie, 1 or 2 tablets) 4 times daily for a maximum duration of 3 weeks.

MAIN OUTCOMES AND MEASURES

The primary outcome was the mean of daily pain scores collected during week 1 of treatment measured using the Numerical Pain Rating Scale (NRS). Participants were asked to rate their mean pain over the previous 24 hours daily using an NRS score from 0 to 10, with 0 representing no pain and 10 representing the worst pain imaginable. The key secondary outcomes were EuroQol 5-Dimension 5-Level Questionnaire (EQ-5D-5L) responses, worst pain, medication adverse events, global perceived effect, and return to work.

RESULTS

A total of 120 patients with 1 or more acute orthopedic fractures requiring surgical fixation were randomized, including 59 patients in the strong-opioid group (43 [72.9%] men; mean [SD] age, 36.0 [14.1] years; mean oral morphine equivalent for days 1-7 of 32.9 mg) and 61 patients in the mild opioid group (47 [77.1%] men; mean [SD] age, 38.2 [13.5] years; mean oral morphine equivalent for days 1-7 of 5.5 mg). From days 1 to 7 postdischarge, the mean daily NRS mean pain score was 4.04 (95% Cl, 3.67 to 4.41) in the strong opioid group and 4.54 (95% Cl, 4.17 to 4.90) in the mild opioid group. The between-group difference of the primary outcome was not statistically significant (-0.50 [95% Cl, -1.11 to 0.12]; P = .11) despite a 6-fold increased dose of opioids being delivered in the strong opioid group.

CONCLUSIONS AND RELEVANCE

This study found that treatment with strong opioid medication subacutely was not superior to treatment with milder medication for treatment of pain among patients with surgically managed orthopedic fractures. These findings suggest that ongoing first-line strong opioid use after discharge from the hospital should not be supported.

TRIAL REGISTRATION

Australia New Zealand Clinical Trial Registry No.: ACTRN12616000941460.

Understanding differences in prescription drug misuse between two Texas border communities

Objectives: The misuse of prescription drugs in the U.S. is an alarming public health crisis. Prior research at the U.S.-Mexico border has found high rates of prescription drug misuse, but with rates varying significantly across border communities. We aimed to examine a model of permissive climate measures and stress exposures as potential mediators of community differences in prescription drug misuse at the U.S.-Mexico border.Design: We analyzed data from the U.S.-Mexico Study of Alcohol and Related Conditions (UMSARC). Household, in-person interviews were conducted with Mexican-origin residents of the Texas border cities Laredo (n = 751) and Brownsville/McAllen (n = 814). Interviews assessed past-year misuse of any and pain-reliever prescription drugs. Drug availability, neighborhood safety, exposure to violence/crime, and social support were examined as potential mediators. Analyses were stratified by gender and employed regressions and mediation analysis with Mplus.Results: The past-year prevalence of any prescription drug misuse in Laredo was 26.3% among women and 24.4% among men, and in Brownsville/McAllen was 12.4% among men, and 6.7% among women. Mediation analysis revealed site effects via some of the hypothesized risk factors for men, but not for women. Specifically, for men, site effects on any and pain reliever prescription drug misuse were partially mediated via high drug availability and low family support.Conclusions: Past-year prescription drug misuse was over 3 times the 2015 national prevalence among both men and women in Laredo and calls for immediate attention. Findings regarding the model suggest drug availability and social support may be relevant to understanding community differences in prescription drug misuse among men living at the border, and that additional factors should be investigated to understand misuse among women living at the border.

The impact of community-level prevention strategies on high-dose opioid dispensing rates: 2014-2019

BACKGROUND

Prescription opioids played a major role in the current opioid overdose epidemic. High rates of opioid prescribing and dispensing exposed many people to opioids, and high-dose opioid prescriptions (e.g., 90 morphine milligram equivalents [MME] per day) contributed to increases in opioid overdoses. The Centers for Disease Control and Prevention (CDC) Prevention for States (PfS) program provided funding to jurisdictions ("PfS recipients") with a high burden of opioid-involved overdoses. This paper examines associations between strategies addressing high-dose opioid prescribing and changes in high-dose opioid dispensing.

METHODS

Monthly opioid dispensing data (2014-2019) from IQVIA Xponent were analyzed using longitudinal growth models (LGM) to compare high-dose opioid dispensing rates in the 29 jurisdictions that participated in PfS with rates in non-PfS jurisdictions. Additional models examined associations between specific PfS activities and changes in high-dose dispensing among PfS recipients.

RESULTS

High-dose dispensing rates decreased significantly in both PfS and non-PfS jurisdictions from 2014 to 2019. Rates of high-dose opioid dispensing rates in PfS jurisdictions were not significantly different than those in non-PfS jurisdictions (p = 0.07). Among PfS recipients, multiple activities were associated with decreases in high-dose dispensing rates over time, including moving towards real-time prescription drug monitoring program (PDMP) reporting (p < 0.001) and implementation of opioid dispensing interventions for insurers/ health systems (p < 0.05).

CONCLUSIONS

High-dose opioid dispensing rates decreased throughout the United States from 2014-2019. As the drug epidemic continues to evolve, implementation of prevention activities by state and local partners is important. These findings highlight two potential prevention strategies and activities that jurisdictions can utilize.

Changes in Adolescents' Psychosocial Functioning and Well-Being as a Consequence of Long-Term COVID-19 Restrictions

This work studied self-reports from adolescents on how the COVID-19 pandemic has changed their behaviors, relationships, mood, and victimization. Data collection was conducted between September 2020 and February 2021 in five countries (Sweden, the USA, Serbia, Morocco, and Vietnam). In total, 5114 high school students (aged 15 to 19 years, 61.8% females) responded to our electronic survey. A substantial proportion of students reported decreased time being outside (41.7%), meeting friends in real life (59.4%), and school performance (30.7%), while reporting increased time to do things they did not have time for before (49.3%) and using social media to stay connected (44.9%). One third of the adolescents increased exercise and felt that they have more control over their life. Only a small proportion of adolescents reported substance use, norm-breaking behaviors, or victimization. The overall COVID-19 impact on adolescent life was gender-specific: we found a stronger negative impact on female students. The results indicated that the majority of adolescents could adapt to the dramatic changes in their environment. However, healthcare institutions, municipalities, schools, and social services could benefit from the findings of this study in their work to meet the needs of those young people who signaled worsened psychosocial functioning, increased stress, and victimization.

Association between Lifetime History of Traumatic Brain Injury, Prescription Opioid Use, and Persistent Pain: A Nationally Representative Study

Pain is common among adults with traumatic brain injury (TBI), yet little data exist regarding prevalence of opioid use in this population. The objective of this retrospective cohort study was to evaluate the association between lifetime TBI exposure, opioid use, and pain in a nationally representative sample of 1022 adults aged 50+ who participated in the Health and Retirement Study (HRS). Our primary exposure was lifetime TBI history measured via the Ohio State University TBI Identification Method. We evaluated three alternate TBI exposures (years since most recent TBI, age at first TBI, and number of lifetime TBIs) in sensitivity analyses. We evaluated two outcomes: recent opioid medication use, and moderate-to-severe pain measured over two HRS waves. We classified three pain groups (persistent, intermittent, and no pain). Prevalences of opioid use among individuals with and without TBI were 19.7% and 13.6%, respectively. After adjustment for age, sex, and race, individuals with TBI had a 52% increased risk for opioid use compared with individuals without TBI (relative risk = 1.52, 95% confidence interval: 1.11, 2.04). Individuals with recent TBI (1-10 years ago), first TBI after age 40+, and 2+ lifetime TBIs had greatest risk for opioid use. Compared with individuals without TBI, individuals with TBI had 4.9-times increased odds for persistent versus no pain, and 1.9-times increased odds of intermittent versus no pain. Persistent pain among adults with lifetime TBI is elevated compared with the general population, which may contribute to increased opioid use among persons with TBI, particularly those with recent injuries or multiple lifetime TBIs.

Predictors of chronic opioid therapy in Medicaid beneficiaries with HIV who initiated antiretroviral therapy

The factors associated with chronic opioid therapy (COT) in patients with HIV is understudied. Using Medicaid data (2002–2009), this retrospective cohort study examines COT in beneficiaries with HIV who initiated standard combination anti-retroviral therapy (cART). We used generalized estimating equations on logistic regression models with backward selection to identify significant predictors of COT initiation. COT was initiated among 1014 out of 9615 beneficiaries with HIV (male: 10.4%; female: 10.7%). Those with older age, any malignancy, Hepatitis C infection, back pain, arthritis, neuropathy pain, substance use disorder, polypharmacy, (use of) benzodiazepines, gabapentinoids, antidepressants, and prior opioid therapies were positively associated with COT. In sex-stratified analyses, multiple predictors were shared between male and female beneficiaries; however, chronic obstructive pulmonary disease, liver disease, any malignancy, and antipsychotic therapy were unique to female beneficiaries. Comorbidities and polypharmacy were important predictors of COT in Medicaid beneficiaries with HIV who initiated cART.

Influence of Opioid Prescription Policy on Overdoses and Related Adverse Effects in a Primary Care Population

BACKGROUND

In response to the opioid epidemic, many states have enacted policies limiting opioid prescriptions. There is a paucity of evidence of the impact of opioid prescribing interventions in primary care populations, including whether unintended consequences arise from limiting the availability of prescribed opioids.

OBJECTIVE

Our aim was to compare changes in opioid overdose and related adverse effects rate among primary care patients following the implementation of state-level prescribing policies.

DESIGN

A cohort of primary care patients within an interrupted time series model.

PARTICIPANTS

Electronic medical record data for 62,776 adult (18+ years) primary care patients from a major medical center in Vermont from January 1, 2016, to June 30, 2018.

INTERVENTIONS

State-level opioid prescription policy changes limiting dose and duration.

MAIN MEASURES

Changes in (1) opioid overdose rate and (2) opioid-related adverse effects rate per 100,000 person-months following the July 1, 2017, prescription policy change.

KEY RESULTS

Among primary care patients, there was no change in opioid overdose rate following implementation of the prescribing policy (incidence rate ratio; IRR: 0.64, 95% confidence interval; CI: 0.22-1.88). There was a 78% decrease in the opioid-related adverse effects rate following the prescribing policy (IRR: 0.22, 95%CI: 0.09-0.51). This association was moderated by opioid prescription history, with decreases observed among opioid-naïve patients (IRR: 0.18, 95%CI: 0.06-0.59) and among patients receiving chronic opioid prescriptions (IRR: 0.17, 95%CI: 0.03-0.99), but not among those with intermittent opioid prescriptions (IRR: 0.51, 95%CI: 0.09-2.82).

CONCLUSIONS

Limiting prescription opioids did not change the opioid overdose rate among primary care patients, but it reduced the rate of opioid-related adverse effects in the year following the state-level policy change, particularly among patients with chronic opioid prescription history and opioid-naïve patients. Limiting the quantity and duration of opioid prescriptions may have beneficial effects among primary care patients.

Opioid Misuse among Smokers with Chronic Pain: Relations with Substance Use and Mental Health

Opioid misuse is a significant public health concern with substantial medical, social, and economic costs. Cross cutting the personal and societal effects of this current crisis, opioid misuse is associated with poorer physical and mental health outcomes that impair function across numerous life domains. Importantly, opioid misuse disproportionately affects persons with chronic pain and individuals who smoke tobacco. Despite the higher risk for smokers with chronic pain to engage in opioid misuse, little work has examined how opioid misuse may be related to mental health problems, including other substance use, among this vulnerable group. The current study examined opioid misuse as a predictor of substance use and mental health problems among 187 (M_age = 39.02, SD = 9.94, 74.9% female) daily cigarette smokers with chronic pain who currently use opioids. Results indicated that opioid misuse is associated with greater tobacco (13% of variance), alcohol (27% of variance), and cannabis (22% of variance) problems, as well as anxiety (26% of variance) and depressive symptoms (26% of variance). These results highlight the potential importance of opioid misuse in terms of concurrent substance and mental health problems among smokers with chronic pain. Future work is needed to explicate directionality and temporal ordering in the observed relations.

Endogenous and exogenous opioid effects on oligodendrocyte biology and developmental brain myelination

The elevated presence of opioid receptors and their ligands throughout the developing brain points to the existence of maturational functions of the endogenous opioid system that still remain poorly understood. The alarmingly increasing rates of opioid use and abuse underscore the urgent need for clear identification of those functions and the cellular bases and molecular mechanisms underlying their physiological roles under normal and pathological conditions. This review is focused on current knowledge on the direct and indirect regulatory roles that opioids may have on oligodendrocyte development and their generation of myelin, a complex insulating membrane that not only facilitates rapid impulse conduction but also participates in mechanisms of brain plasticity and adaptation. Information is examined in relation to the importance of endogenous opioid function, as well as direct and indirect effects of opioid analogues, which like methadone and buprenorphine are used in medication-assisted therapies for opioid addiction during pregnancy and pharmacotherapy in neonatal abstinence syndrome. Potential opioid effects are also discussed regarding late myelination of the brain prefrontal cortex in adolescents and young adults. Such knowledge is fundamental for the design of safer pharmacological interventions for opioid abuse, minimizing deleterious effects in the developing nervous system.

Comparative efficacy of a single-session "Empowered Relief" videoconference-delivered group intervention for chronic pain: study protocol for a randomized controlled trial

BACKGROUND

Chronic pain is naturally aversive and often distressing for patients. Pain coping and self-regulatory skills have been shown to effectively reduce pain-related distress and other symptoms. In this trial, the primary goal is to pilot test the comparative efficacy of a single-session videoconference-delivered group pain education class to a waitlist control among patients with chronic pain.

METHODS

Our study is a randomized clinical trial pilot testing the superiority of our 2-h single-session videoconference-delivered group pain education class against a waitlist control. We will enroll 120 adult patients with mixed etiology chronic pain and randomize 1:1 to one of the two study arms. We hypothesize superiority for the pain education class for bolstering pain and symptom management. Team researchers masked to treatment assignment will assess the outcomes up to 3 months post-treatment.

DISCUSSION

This study aims to test the utility of a single-session videoconference-delivered group pain education class to improve self-regulation of pain and pain-related outcomes. Findings from our project have the potential to significantly reduce barriers to effective psychological treatment for pain, optimizing the delivery of increasingly vital online and remote-delivered intervention options.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04546685 . Registered on 04 September 2020.

Housing, opportunities, motivation and engagement (HOME) for homeless youth at-risk for opioid use disorder: study protocol for a randomized controlled trial

Background

Homeless youth experience high rates of substance use disorders, exposures to violence, mental and physical health conditions, and mortality. They have been particularly affected by the opioid crisis. However, no study to date has used a randomized controlled design to test preventive interventions of opioid and other drug use among this vulnerable population. Resolution of youth homelessness through housing and supportive services including prevention services, often referred to as “Housing First,” has great potential to reduce the likelihood for the development of an opioid use disorder as well as other problem behaviors associated with living on the streets. Housing First has been tested through randomized trials among homeless adults with mental health and substance use disorders, but has not been empirically tested for opioid prevention among homeless youth.

Methods

Homeless youth will be recruited from a drop-in shelter site frequented by disconnected youth; they will be screened for eligibility, including current homelessness, age 18–24 years, and not currently meeting criteria for opioid use disorder (OUD). In a controlled trial, 240 youth will then be randomized to one of two conditions, (1) housing + opioid and related risk prevention services, or (2) opioid and related risk prevention services alone. This project utilizes existing efficacious models of prevention to address opioid-related risks, including motivational interviewing, strengths-based outreach and advocacy, and an HIV risk preventive intervention. Follow-up will be conducted at 3, 6, 9 and 12-months post-baseline. The economic cost of each intervention will be determined to support implementation decisions with other providers and their funders.

Discussion

This study will provide essential information for researchers and providers on the efficacy of housing + opioid and related risk prevention services in an RCT for effects on opioid use and mechanisms underlying change. Because youth experiencing homelessness are at increased risk for a variety of adverse outcomes, the proposed intervention may produce substantial health care benefits to the youths and society at large.

Trial registration ClinicalTrials.gov, NCT04135703, Registered October 13, 2019, https://clinicaltrials.gov/ct2/show/NCT04135703?term=NCT04135703&draw=2&rank=1#contacts

Trends in strong opioid prescribing in Ireland: A repeated cross-sectional analysis of a national pharmacy claims database between 2010 and 2019

PURPOSE

Significant increases in opioid utilisation have been reported in many countries in recent decades. This study investigated strong opioid prescribing in Irish General Medical Services (GMS) patients over a 10-year period.

METHODS

A retrospective repeated cross-sectional analysis of a national pharmacy claims database between January 2010 and December 2019 was conducted. Strong opioid prescribing in GMS patients was evaluated, including by route of administration, age (16-64 years and ≥65 years) and gender. Measures of consumption included prescribing prevalence and defined daily dose (DDD)/1000 population/day. Prevalence ratios (PRs) with 95% confidence intervals (CIs), and percentage and absolute changes were determined.

RESULTS

Strong opioid prescribing prevalence increased from 14.43% in 2010 to 16.28% in 2019, with the greatest increase in the ≥65 years age group. Tramadol was the most frequently prescribed product, constituting 63.9% of total strong opioid prescribing. The prescribing prevalence of oxycodone increased from 0.95% in 2010 to 2.68% in 2019 (PR 2.81, 95% CI 2.76, 2.87), with steep increases in oxycodone-naloxone since it became available (PR 5.23, 95% CI 4.98, 5.50). The prescribing prevalence of tapentadol increased from 0.18% to 1.58% between 2012 (first complete year available for reimbursement) and 2019 (PR 8.79, 95% CI 8.43, 9.16). Strong opioid prescribing was highest in females aged ≥65 years.

CONCLUSIONS

This study found an overall increase in strong opioid prescribing in Ireland between 2010 and 2019, particularly in older adults. Tramadol was the most frequently prescribed product, with oxycodone and tapentadol prescribing increasing markedly over the study period.

Identifying risk of opioid use disorder for patients taking opioid medications with deep learning

OBJECTIVE

The United States is experiencing an opioid epidemic. In recent years, there were more than 10 million opioid misusers aged 12 years or older annually. Identifying patients at high risk of opioid use disorder (OUD) can help to make early clinical interventions to reduce the risk of OUD. Our goal is to develop and evaluate models to predict OUD for patients on opioid medications using electronic health records and deep learning methods. The resulting models help us to better understand OUD, providing new insights on the opioid epidemic. Further, these models provide a foundation for clinical tools to predict OUD before it occurs, permitting early interventions.

METHODS

Electronic health records of patients who have been prescribed with medications containing active opioid ingredients were extracted from Cerner's Health Facts database for encounters between January 1, 2008, and December 31, 2017. Long short-term memory models were applied to predict OUD risk based on five recent prior encounters before the target encounter and compared with logistic regression, random forest, decision tree, and dense neural network. Prediction performance was assessed using F1 score, precision, recall, and area under the receiver-operating characteristic curve.

RESULTS

The long short-term memory (LSTM) model provided promising prediction results which outperformed other methods, with an F1 score of 0.8023 (about 0.016 higher than dense neural network (DNN)) and an area under the receiver-operating characteristic curve (AUROC) of 0.9369 (about 0.145 higher than DNN).

CONCLUSIONS

LSTM-based sequential deep learning models can accurately predict OUD using a patient's history of electronic health records, with minimal prior domain knowledge. This tool has the potential to improve clinical decision support for early intervention and prevention to combat the opioid epidemic.

Personality to Prescription Drug Misuse in Adolescents: Testing Affect Regulation, Psychological Dysregulation, and Deviance Proneness Pathways

Background: Fifteen to 25-year-olds are the age group most likely to misuse prescription drugs. Few studies have tested theory-driven models of adolescent risk for prescription drug misuse. Moreover, rarely are distinct pathways to different forms of prescription drug misuse considered. Methods: We tested mediational paths from personality to mental health symptoms to prescription drug misuse, informed by etiological models of addiction. We specified pathways from particular personality traits to unique forms of prescription drug misuse via specific mental health symptoms. We used semi-longitudinal data collected across two waves of the Co-Venture Trial. Our sample included students from 31 Canadian high schools tested in Grade 9 (n = 3,024) and again in Grade 10 (n = 2,869; 95% retention). Personality (hopelessness, anxiety sensitivity, impulsivity, sensation seeking) was assessed in Grade 9. Mental health symptoms (depression, anxiety, ADHD, conduct disorder) and prescription drug misuse (opioids, sedatives/tranquilizers, stimulants) were assessed at both time points. Results: Consistent with the negative affect regulation model, hopelessness was specifically associated with opioid misuse via depressive symptoms, and anxiety sensitivity was specifically associated with sedative/tranquilizer misuse via anxiety symptoms. Consistent with positive affect regulation, sensation seeking was directly associated with stimulant misuse. Consistent with the psychological dysregulation model, impulsivity was associated with stimulant misuse via ADHD symptoms. And consistent with the deviance proneness model, impulsivity was also associated with unconstrained (i.e., all three forms of) prescription drug misuse via conduct disorder symptoms. Conclusions: Screening for adolescents high in hopelessness, anxiety sensitivity, sensation seeking, or impulsivity and providing them with personality-matched cognitive-behavioral interventions may be helpful in preventing or mitigating prescription drug misuse. Our results point to the specific mental health symptoms that are important to target in each of these personality-matched interventions.

Frailty status as a potential factor in increased postoperative opioid use in older adults

BACKGROUND

Prescription opioids are commonly used for postoperative pain relief in older adults, but have the potential for misuse. Both opioid side effects and uncontrolled pain have detrimental impacts. Frailty syndrome (reduced reserve in response to stressors), pain, and chronic opioid consumption are all complex phenomena that impair function, nutrition, psychologic well-being, and increase mortality, but links among these conditions in the acute postoperative setting have not been described. This study seeks to understand the relationship between frailty and patterns of postoperative opioid consumption in older adults.

METHODS

Patients ≥ 65 years undergoing elective surgery with a planned hospital stay of at least one postoperative day were recruited for this cohort study at pre-anesthesia clinic visits. Preoperatively, frailty was assessed by Edmonton Frailty and Clinical Frailty Scales, pain was assessed by Visual Analog and Pain Catastrophizing Scales, and opioid consumption was recorded. On the day of surgery and subsequent hospitalization days, average pain ratings and total opioid consumption were recorded daily. Seven days after hospital discharge, patients were interviewed using uniform questionnaires to measure opioid prescription use and pain rating.

RESULTS

One hundred seventeen patients (age 73.0 (IQR 67.0, 77.0), 64 % male), were evaluated preoperatively and 90 completed one-week post discharge follow-up. Preoperatively, patients with frailty were more likely than patients without frailty to use opioids (46.2 % vs. 20.9 %, p = 0.01). Doses of opioids prescribed at hospital discharge and the prescribed morphine milligram equivalents (MME) at discharge did not differ between groups. Seven days after discharge, the cumulative MME used were similar between cohorts. However, patients with frailty used a larger fraction of opioids prescribed to them (96.7 % (31.3, 100.0) vs. 25.0 % (0.0, 83.3), p = 0.007) and were more likely (OR 3.7, 95 % CI 1.13-12.13) to use 50 % and greater of opioids prescribed to them. Patients with frailty had higher pain scores before surgery and seven days after discharge compared to patients without frailty.

CONCLUSIONS

Patterns of postoperative opioid use after discharge were different between patients with and without frailty. Patients with frailty tended to use almost all the opioids prescribed while patients without frailty tended to use almost none of the opioids prescribed.