Opioids

Abstract

In the last decade, critical-care nurses have seen a surge in acute opioid overdose admissions to intensive care units; there have also been significant increases in intensive care unit admissions due to opioid-related illness such as dependence, tolerance, and hyperalgesia. Despite these issues, opioids continue to be the criterion standard of pain management, and the search for opioid alternatives has not produced a clear replacement. A contributor to this problem has been the prevailing opinion that once bound to a receptor, all opioids engaged in the same types of intracellular signaling, which resulted in the same types of responses, only differing in the magnitude of those responses.Contemporary research with G-protein-coupled receptor models (eg, opioids) has demonstrated that this oversimplification is incorrect or incomplete. Understanding the complexity of opioid pharmacodynamics and pharmacokinetics helps us to grasp the intricacies of opioid-related adverse effects. Although there are many potential adverse effects related to opioids, this review focuses on the major adverse effects commonly seen in critical care, namely, respiratory depression, tolerance, hyperalgesia, and central sensitization. In addition, a case study has been incorporated to aid in understanding of strategies nurses can incorporate into their practices: that help mitigate the development of these effects.

Microglial inflammation modulates opioid analgesic tolerance

“…Opioids function pre‐synaptically and post‐synaptically by binding to their receptors on cell membranes. It is known that the binding of an opioid to the μ‐opioid receptor (MOR) transduces receptor phosphorylation, facilitating the release of G‐protein subunits and initiation of a cascade leading to reduction of adenylyl cyclase, decrease in intracellular cyclic adenosine monophosphate (cAMP) levels, and regulation of ion channels (Hines & Owings, 2021; Pepe et al, 2004). These signaling events inhibit neurotransmitter release to induce hyperpolarization of the cell membranes and modulate the activation of nociceptors, ultimately leading to analgesia.…”