Profile of extended-release oxycodone/acetaminophen for acute pain

Mary Hanna Bekhit1–51David Geffen School of Medicine, 2Ronald Reagan UCLA Medical Center, 3UCLA Ambulatory Surgery Center, 4UCLA Wasserman Eye Institute, 5UCLA Martin Luther King Community Hospital, University of California Los Angeles, Los Angeles, CA, USA Abstract: This article provides a historical and pharmacological overview of a new opioid analgesic that boasts an extended-release (ER) formulation designed to provide both immediate and prolonged analgesia for up to 12 hours in patients who are experiencing acute pain. This novel medication, ER oxycodone/acetaminophen, competes with current US Food and Drug Administration (FDA)-approved opioid formulations available on the market in that it offers two benefits concurrently: a prolonged duration of action, and multimodal analgesia through a combination of an opioid (oxycodone) with a nonopioid component. Current FDA-approved combination analgesics, such as Percocet (oxycodone/acetaminophen), are available solely in immediate-release (IR) formulations. Keywords: opioid, analgesic, xartemis, acute postsurgical pain, substance abuse, acetaminophen, extended release&nbsp

Transgene-mediated expression of tumor necrosis factor soluble receptor attenuates morphine tolerance in rats

Opiate/narcotic analgesics are the most effective treatments for chronic severe pain, but their clinical utility is often hampered by the development of analgesic tolerance. Recent evidence suggests chronic morphine may activate glial cells to release proinflammatory cytokines. In this study, we used herpes simplex virus (HSV) vectors-based gene transfer to dorsal root ganglion to produce a local release of p55 TNF soluble receptor in the spinal cord in rats with morphine tolerance. Subcutaneous inoculation of HSV vectors expressing p55 TNF soluble receptor into the plantar surface of the hindpaws, enhanced the antinociceptive effect of acute morphine in rats. Subcutaneous inoculation of those vectors into hindpaws also delayed the development of chronic morphine tolerance in rats. TNF soluble receptor expressed by HSV vector reduced gene transcription of mRNA of spinal TNFα and IL-1β induced by repeated morphine. Furthermore, we found that TNF soluble receptor mediated by HSV, reversed the upregulation of TNFα, IL-1β and phosphorylation of p38 mitogen-activated protein kinase (MAPK) induced by repeated morphine. These results support the concept that proinflammatory cytokines may play an important role in the pathogenesis induced by morphine. This study provides a novel approach to treating morphine tolerance

Morphine hyperalgesia gated through microglia-mediated disruption of neuronal Cl− homeostasis

A major unresolved issue in treating pain is the paradoxical hyperalgesia produced by the gold-standard analgesic morphine and other opiates. We found that hyperalgesia-inducing treatment with morphine resulted in downregulation of the K(+)-Cl(-) co-transporter KCC2, impairing Cl(-) homeostasis in rat spinal lamina l neurons. Restoring the anion equilibrium potential reversed the morphine-induced hyperalgesia without affecting tolerance. The hyperalgesia was also reversed by ablating spinal microglia. Morphine hyperalgesia, but not tolerance, required μ opioid receptor-dependent expression of P2X4 receptors (P2X4Rs) in microglia and μ-independent gating of the release of brain-derived neurotrophic factor (BDNF) by P2X4Rs. Blocking BDNF-TrkB signaling preserved Cl(-) homeostasis and reversed the hyperalgesia. Gene-targeted mice in which Bdnf was deleted from microglia did not develop hyperalgesia to morphine. However, neither morphine antinociception nor tolerance was affected in these mice. Our findings dissociate morphine-induced hyperalgesia from tolerance and suggest the microglia-to-neuron P2X4-BDNF-KCC2 pathway as a therapeutic target for preventing hyperalgesia without affecting morphine analgesia

Prescription Opioid Fatalities: Examining Why the Healer Could be the Culprit

© 2018, Springer International Publishing AG, part of Springer Nature. Prescription opioid use has increased rapidly in developed countries, as have fatalities and other related adverse events. This review examines the intrinsic characteristics of opioids, including their mechanisms of action and pharmacokinetic and pharmacodynamic properties, to determine how the use of a regonised pharmacological remedy for a medically confirmed ailment could result in an accidental fatality. Opioids trigger biological processes that inhibit their own therapeutic effect. Prolonged use of opioids can result in activation of pronociceptive systems, leading to opioid-induced hyperalgesia and tolerance, while opioid metabolites can antagonise the antinociceptive action of the parent drug, also leading to opioid-induced hyperalgesia and tolerance. Pain stimulates respiration and counteracts the respiratory depression effect of opioids. Analgesia from opioids leads to loss of this protective mechanism, leading to increased risk of death due to respiratory failure. Increased patient counseling during opioid prescribing and dispensing, and limiting prescription to short-term use in non-malignant pain, may decrease the adverse effects of opioids. The vast majority of patients who unintentionally experience serious adverse events from pharmaceutical opioids do not start out as drug seekers. Even opioid use within prescribing guidelines can place some patients at risk of death and may prevent patients from seeking help for prescription opioid dependence