High opioids tolerance due to transmucosal fentanyl abuse

Design, synthesis, evaluation, pharmacophore modeling, and 3D-QSAR of lappaconitine analogs as potential analgesic agents

Alleviating pain is crucial for patients with various diseases. This study aimed to enhance the analgesic properties of lappaconitine, a natural drug, through structural modifications. Specifically, carbamate analgesic active fragments were innovatively introduced at multiple sites on the benzene ring of lappaconitine. A total of 53 lappaconitine analogs were synthesized and evaluated. Compounds 5a, 5c, 5e, 6, and 15j addressed the narrow therapeutic window of lappaconitine, enhancing drug safety. Notably, carbamate analogs exhibited significantly enhanced analgesic activity, with compounds 5a and 5c having ED50 values of 1.2 and 1.6 mg/kg, respectively, indicating higher potency than lappaconitine (3.5 mg/kg). A metabolic analysis of compound 5e was conducted in mice, revealing its primary metabolic processes and metabolites, and providing preliminary exploration for the druggability. Given the multiple analgesic targets of lappaconitine, its analgesic mechanism remains inconclusive. This study, for the first time, analyzed the pharmacological activity characteristics of the lappaconitine analogs using a pharmacophore model and established a three-dimensional quantitative structure-activity relationship (3D-QSAR) to elucidate the quantitative relationship between the structures of the synthesized compounds and their analgesic activities. These findings provide valuable guidance for future structural modification and optimization of analgesic drugs.

Systematic review on intentional non-medical fentanyl use among people who use drugs

Objectives

Fentanyl is a highly potent opioid and has, until recently, been considered an unwanted contaminant in the street drug supply among people who use drugs (PWUD). However, it has become a drug of choice for an increasing number of individuals. This systematic review evaluated intentional non-medical fentanyl use among PWUD, specifically by summarizing demographic variance, reasons for use, and resulting patterns of use.

Methods

The search strategy was developed with a combination of free text keywords and MeSH and non-MeSH keywords, and adapted with database-specific filters to Ovid MEDLINE, Embase, Web of Science, and PsychINFO. Studies included were human studies with intentional use of non-medical fentanyl or analogues in individuals older than 13. Only peer-reviewed original articles available in English were included.

Results

The search resulted in 4437 studies after de-duplication, of which 132 were selected for full-text review. Out of 41 papers included, it was found that individuals who use fentanyl intentionally were more likely to be young, male, and White. They were also more likely to have experienced overdoses, and report injection drug use. There is evidence that fentanyl seeking behaviours are motivated by greater potency, delay of withdrawal, lower cost, and greater availability.

Conclusions

Among PWUD, individuals who intentionally use fentanyl have severe substance use patterns, precarious living situations, and extensive overdose history. In response to the increasing number of individuals who use fentanyl, alternative treatment approaches need to be developed for more effective management of withdrawal and opioid use disorder.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42021272111.

Design, synthesis, and biological evaluation of low-toxic lappaconitine derivatives as potential analgesics

The C₁₈-diterpenoid alkaloid lappaconitine (LA) is a non-addictive analgesic used in China. The toxicity (LD₅₀ = 11.7 mg/kg) limits its application. Two series of LA derivatives, including amides and sulfonamides (1-93), were designed and synthesized by modification on their C4 acetamidobenzoate side chains in this work. In vivo analgesic activity and toxicity of all derivatives were evaluated, and the structure-activity relationship was summarized. Six lead compounds (35, 36, 39, 49, 70, and 89) exhibited approximate analgesic activity to LA but with significantly reduced toxicity. The therapeutic index of these compounds is 14-30 times that of LA. In vivo metabolism study of the lead compounds 39, 49, 70, and 89 were conducted by UPLC-MS^E, indicating the reason for the low toxicity of the potential derivatives might be they are difficult to metabolize to toxic metabolite N-deacetyllappaconitine compared to LA. The effects of lead compounds on sodium channels and hERG channels were also studied by ion channel reader (ICR) which further revealed their analgesic and toxicity-attenuating mechanisms. Sodium channel assay revealed that the analgesic mechanism of these lead compounds was inhibiting the Na_v 1.7 channels. Taken together, compound 39 was provided as a new analgesic lead compound with significantly low toxicity and comparable activity to LA.

Patient With Very High Opioid Tolerance Enrolled in Opioid Agonist Treatment: A Case Report

BACKGROUND

Fentanyl and fentanyl analogs have invaded the street-sourced opioid market in North America which has resulted in an unprecedented number of unintentional opioid overdoses. Existing guidelines to treat opioid use disorder are based on evidence that was developed when heroin was the primary street-sourced opioid and proposed dosages of opioid agonist treatments are increasingly inadequate to address patients with high opioid tolerances.

CASE SUMMARY

The authors examine one case study of a patient with an extremely high opioid tolerance and review how responsive dose adjustments outside of the recognized maximum doses allowed for meaningful functional outcomes.

DISCUSSION

This case demonstrates how patient-centered dose responses with a focus on functional outcomes supersede existing opioids agonist treatment dosing ranges, especially in the context of a patient with a higher than typical opioid tolerance.

Synthetic opioids: a review and clinical update

The term 'opioids' refers to both the natural compounds ('opiates') which are extracted from the opium poppy plant (Papaver somniferum) and their semi-synthetic and synthetic derivatives. They all possess relatively similar biochemical profiles and interact with the opioid receptors within the human body to produce a wide range of physiological effects. They have historically been used for medicinal purposes, their analgesic and sedative effects, and in the management of chronic and severe pain. They have also been used for non-medicinal and recreational purposes to produce feelings of relaxation, euphoria and well-being. Over the last decade, the emergence of an illegal market in new synthetic opioids has become a major global public health issue, associated with a substantial increase in unintentional overdoses and drug-related deaths. Synthetic opioids include fentanyl, its analogues and emerging non-fentanyl opioids. Their popularity relates to changes in criminal markets, pricing, potency, availability compared to classic opioids, ease of transport and use, rapid effect and lack of detection by conventional testing technologies. This article expands on our previous review on new psychoactive substances. We now provide a more in-depth review on synthetic opioids and explore the current challenges faced by people who use drugs, healthcare professionals, and global public health systems.

Intranasal Fentanyl Versus Placebo for Treatment of Episodic Breathlessness in Hospice Patients With Advanced Nonmalignant Diseases

CONTEXT

Episodic breathlessness is a distressing and difficult to treat symptom because of its short duration. Fast actioned intranasal fentanyl (INF) is potentially more suitable than oral opioids.

OBJECTIVES

To examine the feasibility, preliminary efficacy, and safety of INF for the treatment of episodic breathlessness from advanced nonmalignant conditions in hospice patients.

METHODS

Phase IIB, double-blind, randomized controlled, multisite, INF citrate solution vs. placebo crossover feasibility study. Opioid-tolerant patients were to treat six episodes of breathlessness using INF spray. The primary outcome was change in the Visual Analogue Scale for dyspnea (VAS-D) score from baseline to 15 minutes after study drug's administration (VAS-D₁₅). Other outcomes were to collect demographic data and determine the use of rescue medications, safety, and feasibility of the study design.

RESULTS

Twenty-one of 49 eligible patients were enrolled, and 19 (90%) patients completed the study. The mean difference in VAS-D₁₅ between fentanyl and placebo was -3.37 mm (95% CI = -10.35 to 3.61 mm; P = 0.337). There was no statistically significant or clinically meaningful difference between INF and placebo in relieving the sensation of discomfort in episodic breathlessness. No significant drug-related adverse event or detrimental effect on vital signs was observed.

CONCLUSION

We found no difference between INF and placebo in relieving episodic breathlessness in nonmalignant conditions. INF was well tolerated, and the study design proved to be feasible in hospice patients with advanced diseases. Future study using higher concentration of fentanyl solution may be warranted.

Novel Synthetic Opioids: The Pathologist's Point of View

Background: New Psychoactive Substances (NPS) constitute a broad range of hundreds of natural and synthetic drugs, including synthetic opioids, synthetic cannabinoids, synthetic cathinones, and other NPS classes, which were not controlled from 1961 to 1971 by the United Nations drug control conventions. Among these, synthetic opioids represent a major threat to public health. Methods: A literature search was carried out using public databases (such as PubMed, Google Scholar, and Scopus) to survey fentanyl-, fentanyl analogs-, and other synthetic opioid-related deaths. Keywords including “fentanyl”, “fentanyl analogs”, “death”, “overdose”, “intoxication”, “synthetic opioids”, “Novel Psychoactive Substances”, “MT-45”, “AH-7921”, and “U-47700” were used for the inquiry. Results: From our literature examination, we inferred the frequent implication of fentanyls and synthetic opioids in side effects, which primarily affected the central nervous system and the cardiovascular and pulmonary systems. The data showed a great variety of substances and lethal concentrations. Multidrug-related deaths appeared very common, in most reported cases. Conclusions: The investigation of the contribution of novel synthetic opioid intoxication to death should be based on a multidisciplinary approach aimed at framing each case and directing the investigation towards targeted toxicological analyses.