Controlling the “Opioid Epidemic”: A Novel Chemical Entity (NCE) to Reduce or Supplant Opiate Use for Chronic Pain (original) (raw)
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Journal of Pharmacology and Experimental Therapeutics, 2013
The most highly abused prescription drugs are opioids used for the treatment of pain. Physician-reported drug-seeking behavior has resulted in a significant health concern among doctors trying to adequately treat pain while limiting the misuse or diversion of pain medications. In addition to abuse liability, opioid use is associated with unwanted side effects that complicate pain management, including opioid-induced emesis and constipation. This has resulted in restricting long-term doses of opioids and inadequate treatment of both acute and chronic debilitating pain, demonstrating a compelling need for novel analgesics. Recent reports indicate that adaptations in endogenous substance P/neurokinin-1 receptor (NK 1 ) are induced by chronic pain and sustained opioid exposure, and these changes may contribute to processes responsible for opioid abuse liability, emesis, and analgesic tolerance. Here, we describe a multifunctional mu-/delta-opioid agonist/NK 1 antagonist compound [Tyr-D-Ala-Gly-Phe-Met-Pro-Leu-Trp-NH-Bn(CF 3 ) 2 (TY027)] that has a preclinical profile of excellent antinociceptive efficacy, low abuse liability, and no opioid-related emesis or constipation. In rodent models of acute and neuropathic pain, TY027 demonstrates analgesic efficacy following central or systemic administration with a plasma half-life of more than 4 hours and central nervous system penetration. These data demonstrate that an innovative opioid designed to contest the pathology created by chronic pain and sustained opioids results in antinociceptive efficacy in rodent models, with significantly fewer side effects than morphine. Such rationally designed, multitargeted compounds are a promising therapeutic approach in treating patients who suffer from acute and chronic pain. Dual acting opioid agonist/NK 1 antagonist does not produce antinociceptive tolerance or reward in an animal model of neuropathic pain. Society for Neuroscience; 2009 Oct 11-17; Chicago, IL; and Largent-Milnes TM, Yamamoto T, Nair P, Navratilova E, Davis P, Hruby VJ, Yamamura HI, Lai J, Porreca F, and Vanderah TW (2008) Dual acting opioid agonist/NK1 antagonist peptide reverses neuropathic pain in an animal model without opioid side effects.
New paradigms and tools in drug design for pain and addiction
The AAPS Journal, 2006
New modalities providing safe and effective treatment of pain, especially prolonged pathological pain, have not appeared despite much effort. In this mini-review/overview we suggest that new paradigms of drug design are required to counter the underlying changes that occur in the nervous system that may elicit chronic pain states. We illustrate this approach with the example of designing, in a single ligand, molecules that have agonist activity at m and d opioid receptors and antagonist activities at cholecystokinin (CCK) receptors. Our fi ndings thus far provide evidence in support of this new approach to drug design. We also report on a new biophysical method, plasmon waveguide resonance (PWR) spectroscopy, which can provide new insights into information transduction in G-protein coupled receptors (GPCRs) as illustrated by the d opioid receptor.
Potential for Kappa-Opioid Receptor Agonists to Engineer Nonaddictive Analgesics: A Narrative Review
Anesthesia & Analgesia, 2020
A serious adverse effect of prescription opioid analgesics is addiction, both to these analgesics and to illicit drugs like heroin that also activate the µ-opioid receptor (MOR). Opioid use disorder (OUD) and opioid overdose deaths represent a current American health crisis, and the prescription of opioid analgesics has contributed significantly to this crisis. While prescription opioids are highly effective analgesics, there currently exists no facile way to use them for extended periods without the risk of addiction. If addiction caused by MOR-targeting analgesics could be blocked by blending in a new “antiaddiction” ingredient that does not diminish analgesia and does not introduce its own therapeutically limiting side effects, then continued clinical use of prescription opioids for treating pain could be maintained (or even enhanced) instead of curtailed. In this narrative review, we contextualize this hypothesis, first with a brief overview of the current American opioid addict...
Analysis of natural product regulation of opioid receptors in the treatment of human disease
Pharmacology & Therapeutics, 2018
Opioid receptors (ORs), µOR, δOR, κOR and ORL1 mediate numerous signaling cascades, most importantly, through the modulation of ion channels. Research demonstrates the role of OR mediated signal transduction in treating pain, cancer, neurodegenerative disorders and cardiac insults. Yet, the primary application of drugs that modulate ORs is analgesia. Current opioids like morphine that are mainly µOR orthosteric agonists attract many undesirable side-effects (constipation, urinary retention, respiratory depression and hypotension) and the existing modus operandi against these is the inclusion of a µOR antagonist (for example. naloxone) which itself produces side-effects. As such, there is a current thrust to delineate the anti-nociceptive pathways mediated by ORs from the pathways involved in their induction of debilitating side-effects, in order to develop enhanced lead molecules. This review discusses the effects of natural products on the OR-induced signaling cascades and compares these to current synthetic leads and drugs. Important to these discussions is the complexity of OR signaling which involves OR trafficking, de-and re-sensitization, homo-and hetero-dimerization, the type of ligand binding (agonist, antagonist, reverse antagonist, orthosteric and allosteric agonist and antagonist in the context of biased agonism) and reasons for dysregulation that primarily occur because of inter-individual variations. Our current understanding of the different forms of ORs has expanded, thus introducing the concept of allosterism, which is also discussed. The authors present possible combination therapies to be explored towards developing the 'Holy Grail' of analgesics, for example, ignavine, the natural µOR positive allosteric modulator (PAM) with codeine and the natural fascaplysin, a balanced agonist with fentanyl. There remain many gaps in natural products research on ORs, more so on ORL1 and δ-and ҡ receptors. Furthermore, additional exploration of ORs' modulation is needed for ameliorating other associated disease conditions of global concern.
Replacement of current opioid drugs focusing on MOR-related strategies
Pharmacology & Therapeutics, 2020
The scarcity and limited risk/benefit ratio of painkillers available on the market, in addition to the opioid crisis, warrant reflection on new innovation strategies. The pharmacopoeia of analgesics is based on products that are often old and derived from clinical empiricism, with limited efficacy or spectrum of action, or resulting in an unsatisfactory tolerability profile. Although they are reference analgesics for nociceptive pain, opioids are subject to the same criticism. The use of opium as an analgesic is historical. Morphine was synthesized at the beginning of the 19th century. The efficacy of opioids is limited in certain painful contexts and these drugs can induce potentially serious and fatal adverse effects. The current North American opioid crisis, with an ever-rising number of deaths by opioid overdose, is a tragic illustration of this. It is therefore legitimate to develop research into molecules likely to maintain or increase opioid efficacy while improving their tolerability. Several avenues are being explored including targeting of the mu opioid receptor (MOR) splice variants, developing biased agonists or targeting of other receptors such as heteromers with MOR. Ion channels acting as MOR effectors, are also targeted in order to offer compounds without MOR-dependent adverse effects. Another route is to develop opioid analgesics with peripheral action or limited central nervous system (CNS) access. Finally, endogenous opioids used as drugs or compounds that modify the metabolism of endogenous opioids (Dual ENKephalinase Inhibitors) are being developed. The aim of the present review is to present these various targets/strategies with reference to current indications for opioids, concerns about their widespread use, particularly in chronic non-cancer pains, and ways of limiting the risk of opioid abuse and misuse.
Progress in the development of more effective and safer analgesics for pain management
European Journal of Medicinal Chemistry, 2019
Opioid analgesics have been used for thousands of years in the treatment of pain and related disorders, and have become among the most widely prescribed medications. Among opioid analgesics, mu opioid receptor (MOR) agonists are the most commonly used and are indicated for acute and chronic pain management. However, their use results in a plethora of well-described side-effects. From selective delta opioid receptor (DOR) and kappa opioid receptor (KOR) agonists to multitarget MOR/DOR and MOR/KOR ligands, medicinal chemistry provided different approaches aimed at the development of opioid analgesics with an improved pharmacological and tolerability fingerprint. The emergent medicinal chemistry strategy to develop ameliorated opioid analgesics is based upon the concept that functional selectivity for G-protein signalling is necessary for the therapeutic effect, whether b-arrestin recruitment is mainly responsible for the manifestation of side effects, including the development of tolerance after repeated administrations. This review summarises most relevant biased MOR, DOR, KOR and multitarget MOR/ DOR ligands synthesised in the last decade and their pharmacological profile in "in vitro" and "in vivo" studies. Such biased ligands could have a significant impact on modern drug discovery and represent a new strategy for the development of better-tolerated drug candidates.
Nature Reviews Neurology
Pain medication plays an important role in the treatment of acute and chronic pain conditions, but some drugs, opioids in particular, have been overprescribed or prescribed without adequate safeguards, leading to an alarming rise in medication-related overdose deaths. The NIH Helping to End Addiction Long-term (HEAL) Initiative is a trans-agency effort to provide scientific solutions to stem the opioid crisis. One component of the initiative is to support biomarker discovery and rigorous validation in collaboration with industry leaders to accelerate high-quality clinical research into neurotherapeutics and pain. The use of objective biomarkers and clinical trial end points throughout the drug discovery and development process is crucial to help define pathophysiological subsets of pain, evaluate target engagement of new drugs and predict the analgesic efficacy of new drugs. In 2018, the NIH-led Discovery and Validation of Biomarkers to Develop Non-Addictive Therapeutics for Pain wo...
New approaches to treating pain
Bioorganic & Medicinal Chemistry Letters, 2016
Pain is the most common reason for patients seeking medical care resulting in an estimated world market for analgesics of more than USD 50 billion. Pain is a highly complex, heterogeneous and dynamic process characterized by specific patterns of phenotypic sensory neuronal change. Current treatment options for pain include opioids and non-opioid analgesics, acetaminophen and non-steroidal antiinflammatory drugs and other drug classes such as antidepressants and anticonvulsants and a combination thereof. Novel approaches are focusing on the optimization of sideeffect profiles of opioid based analgesics, the improvement of selectivity for specific opioid receptors, or by addressing molecular gateways implicated in pain. Promising candidates in development target various types of voltage-gated ion channels and receptors for capsaicin and analogues. Currently, after decades of pain research it has to be stated that the assessment, prevention and treatment of pain in industrialized countries as well as in low-income and middle-income countries are neither adequate nor equitable. Further research is needed so that specifically chronic pain control can be improved and individualized.
Recent advances in pain management
International Journal of Basic & Clinical Pharmacology
Pain is one of the most common complaints for which patients approach physicians. In spite of this there is a huge unmet need for developing medications for pain that are safe and efficacious. Owing to the heterogeneity of clinical pain and complex pathophysiology, target identification for drug development is difficult. Preclinical models have also proven unreliable for the development of novel analgesics. Recent advances in understanding the physiology of nociception has enabled the development of novel analgesics including abuse deterrent opioids, drugs targeting several receptors, ion channels and enzymes. This review will attempt to cover the physiology of nociception focusing on the novel targets, the challenges in development of novel analgesics and give an overview of the recently developed drugs and those in the pipeline for the management of pain.