Perioperative and Intraoperative Pain and Anesthetic Care of the Chronic Pain and Cancer Pain Patient Receiving Chronic Opioid Therapy

Involvement of the Opioidergic Mechanism in the Analgesic Potential of a Novel Indazolone Derivative: Efficacy in the Management of Pain, Neuropathy, and Inflammation Using In Vivo and In Silico Approaches

Indazolones possess interesting pharmacological activities. The search for indazole and indazolone-containing nuclei as drugs is an important research area of medicinal chemistry. The current work aims to evaluate a novel indazolone derivative against in vivo and in silico targets of pain, neuropathy, and inflammation. An indazolone derivative (ID) was synthesized and characterized using advanced spectroscopic techniques. Well-established animal models of abdominal constriction, hot plate, tail immersion, carrageenan paw edema, and Brewer's yeast-induced pyrexia were employed for evaluating the potential of the ID at different doses (20-60 mg kg^-1). Nonselective GABA antagonists, opioid antagonist naloxone (NLX) and pentylenetetrazole (PTZ), were employed to assess the potential role of GABAergic and opioidergic processes. The antineuropathic potential of the drug was evaluated using a vincristine-induced neuropathic pain model. In silico studies were performed to assess any possible interactions of the ID with pain target sites like cyclooxygenases (COX-I/II), GABA_A, and opioid receptors. This study revealed that the selected ID (doses of 20-60 mg kg^-1) efficiently hampered chemically and thermally induced nociceptive responses, producing significant anti-inflammatory and antipyretic effects. These effects produced by the ID were dose-dependent (i.e., 20-60 mg kg^-1 and p range of 0.001-0.01) and significant in comparison to standards (p < 0.001). Antagonistic studies with NLX (1.0 mg kg^-1) and PTZ (15.0 mg kg^-1) revealed the involvement of the opioidergic mechanism rather than the GABAergic mechanism. The ID showed promising anti-static allodynia effects as well. In silico studies revealed preferential binding interactions of the ID with cyclooxygenases (COX-I/II), GABA_A, and opioid receptors. According to the results of the current investigation, the ID may serve in the future as a therapeutic agent for the treatment of pyrexia, chemotherapy-induced neuropathic pain, and nociceptive inflammatory pain.

GC-MS Analysis and Various In Vitro and In Vivo Pharmacological Potential of Habenaria plantaginea Lindl

Background. The current study aims to give a scientific origin for employing Habenaria plantaginea Lindl. as a potential candidate against nociception, inflammation, and pyrexia. The pharmacological studies were performed on crude extract and subfractions. In the gas chromatography-mass spectroscopy analysis, a total of 21 compounds were identified. The plant samples were displayed for in vitro anti-inflammatory potentials. The observed IC₅₀ for chloroform against cyclooxygenase-2 and 5-lipoxygenase enzymes was 33.81 and 26.74 μg/mL, respectively. The in vivo activities were prerequisites with the acute toxicity studies. In carrageenan-induced inflammation, the chloroform fraction exhibited 46.15% inhibition similar to that of standard drug diclofenac sodium 47.15%. Likewise, in the acetic acid-induced writhing test, the ethyl acetate fraction displayed 71.42% activity, which was dose-dependent as that of standard drug. In Brewer's yeast-induced antipyretic activity, a significant decrease in rectal volume was observed after 30, 60, and 90 minutes. Moreover, the results of this study indicated that the chloroform and ethyl acetate fractions inhibited nociception, inflammation, and pyrexia dose dependently. Likewise, mechanistic insights indicated that naloxone antagonized the antinociceptive effect of chloroform and ethyl acetate fractions, thereby signifying the involvement of opioidergic mechanisms respectively. These results suggest that these molecules present in this plant have synergistically beneficial potential for the cure and management of analgesia, inflammation, and pyrexia.

Preoperative Management of Opioid and Nonopioid Analgesics: Society for Perioperative Assessment and Quality Improvement (SPAQI) Consensus Statement

There is a lack of guidelines for preoperative dosing of opioid and nonopioid pain medications for surgical patients, which can lead to suboptimal preoperative pain control. The Society for Perioperative Assessment and Quality Improvement identified preoperative dosing of opioid and nonopioid analgesics as an area in which consensus could improve patient care. The aim of this guideline is to provide consensus that will allow perioperative physicians to make optimal recommendations regarding preoperative pain medication dosing. Six categories of pain medications were identified: opioid agonists, opioid antagonists, opioid agonist-antagonists, acetaminophen, muscle relaxants, and triptans/headache medications. We then used a Delphi survey technique to develop consensus recommendations for preoperative dosing of individual medications in each of these groups.

Chronic pain patient and anaesthesia

Severe chronic pain is often devastating for the affected individuals causing substantial suffering, health impairment, and a very low quality of life, including significant negative consequences for the patient and for society. Patients with complex pain disorders are seen often in relation to anaesthesia. They deserve special attention and require long time hospitalization and multiple contacts with health-care providers after discharge from hospital. A wider adoption of best perioperative and intraoperative pain management practice is required. This paper reviews current knowledge of perioperative and intraoperative pain management and anaesthetic care of the chronic pain patient. The individual topics covered include the magnitude of the problem created by chronic pain, the management of the patients taking various types of opioids, tolerance and opioid induced hyperalgesia and the multidisciplinary approach to pain management. The preventive and preemptive strategies for reducing the opioid needs and chronic pain after surgery are reviewed. The last section includes the role of acute pain services and an example of the implementation of a transitional pain service with the various benefits it offers; for example, the decrease of the opioid dose after discharge from the hospital. Patients also receive the continuity of care, with not only pain relief but also improvements in physical functioning, quality of life and emotional stress.

New concepts in opioid analgesia

INTRODUCTION

Opioids are the oldest and most potent drugs for the treatment of severe pain, but they are burdened by detrimental side effects such as respiratory depression, addiction, sedation, nausea, and constipation. Their clinical application is undisputed in acute (e.g. perioperative) and cancer pain, but their long-term use in chronic pain has met increasing scrutiny and has contributed to the current 'opioid crisis.'

AREAS COVERED

This article reviews pharmacological principles and research strategies aiming at novel opioids with reduced side effects. Basic mechanisms underlying pain, opioid analgesia, and other opioid actions are outlined. To illustrate the clinical situation and medical needs, plasticity of opioid receptors, intracellular signaling pathways, endogenous and exogenous opioid receptor ligands, central and peripheral sites of analgesic, and side effects are discussed.

EXPERT OPINION

The epidemic of opioid misuse has taught us that there is a lack of fundamental knowledge about the characteristics and management of chronic pain, that conflicts of interest and validity of models must be considered in the context of drug development, and that novel analgesics with less abuse liability are badly needed. Currently, the most promising perspectives appear to be augmenting endogenous opioid actions and selectively targeting pathological conformations of peripheral opioid receptors.

Perioperative management of patients with cancer pain treated with opioids: a retrospective study

PURPOSE

We retrospectively studied perioperative management of patients receiving opioid treatment for cancer pain to facilitate establishing a standard policy for our institute.

METHODS

Subjects were patients who had been administered strong opioids for cancer pain and had undergone surgery with general anesthesia. We divided the patients into groups C and D. Group C was comprised of patients who had been administered their baseline opioids continuously during the perioperative period, and group D of those who had discontinued baseline opioid use during this period.

RESULTS

We identified 70 evaluable patients, 36 in group C and 34 in group D. The intraoperative anesthesia courses were similar, being uneventful, in all cases. With respect to postoperative adverse effects within 24 h after awakening from anesthesia, severe adverse effects (additional administration of more than four analgesics and intense agitation) were significantly more frequent in group D than in group C (12 vs 1, respectively. p = 0.004). Univariate analysis revealed that baseline opioid discontinuation was the only factor associated with severe adverse effects [odds ratio 12.6, 95% confidence interval (1.49-105.8), p = 0.01].

CONCLUSION

Discontinuation of baseline opioid increased adverse effects in the early postoperative period, which were attributed to exacerbation of early postoperative pain.

Management of acute pain in patients on treatment with opioids

The use of opioids for both benign and cancer-related chronic pain has increased exponentially over the last few years. For this reason, increasing numbers of such patients are presenting for surgery. It is known that continuous use of opioids is associated with an increase in postoperative analgesic requirements. This is believed to be mediated by the development of tolerance and opioid-induced hyperalgesia. Patients treated with opioids have special needs in the perioperative setting and it is the anesthesiologist's responsibility to manage these needs optimally. The aim of the present paper is to briefly orient the reader in the management of postoperative pain in patients chronically treated with licit opioids.

Management of the patient with chronic pain

Chronic pain is a significant complex problem in the perioperative environment. The management of patients with chronic pain has presented new challenges to anesthesia providers in the perioperative setting. The treatment of pain is often inadequate, and patients with preexisting chronic pain are not being managed properly. Although numerous techniques for intraoperative analgesia have been established, no official guidelines have been published for the growing population of patients with chronic pain. This article provides insight into and awareness of the various elements that should be addressed, along with interventions for the patient with chronic pain in the perioperative setting.

Managing a chronic pain patient in the perioperative period

The chronic pain patient with and without chronic opioid medication is at risk for under- and overtreatment perioperatively. Careful planning of the perioperative period by the anesthesiologist, the pain service and the surgeon is crucial. Epidural analgesia requires reduction of preoperative opioid doses to a maximum of 50% to avoid withdrawal as well as continuous postanesthesia care unit-monitoring for the first 24 hours. Brief cognitive behavioral interventions pre- and postoperatively contribute to successful pain management. The perioperative period may be used to re-evaluate the patient's opioid requirements. A follow-up by an experienced pain management service should be available after discharge of the chronic pain patient. Individualized assessment by a pain management team is necessary for this increasing group of patients. This report is adapted from paineurope 2013; Issue 2, ©Haymarket Medical Publications Ltd., and is presented with permission. paineurope is provided as a service to pain management by Mundipharma International, LTD. and is distributed free of charge to healthcare professionals in Europe. Archival issues can be accessed via the website: http://www.paineurope.com at which European health professionals can register online to receive copies of the quarterly publication.

Opioids, sensory systems and chronic pain

Opioids are the oldest and most potent drugs for the treatment of severe pain. Their clinical application is undisputed in acute pain (e.g. associated with trauma or surgery) but their long-term use in chronic pain has met increasing scrutiny. Therefore, this article will review sensory mechanisms related to opioid analgesia and side effects with a special emphasis on chronic pain. Central and peripheral sites of analgesic actions and side effects, as well as conventional and novel opioid compounds will be discussed. Since pain is a complex bio-psycho-social phenomenon, non-pharmacological considerations important for the understanding of opioid analgesic efficacy are also included. Finally, examples of challenging clinical situations such as the perioperative management of patients receiving long-term opioid treatment are illustrated.

Perioperative management of the child on long-term opioids

The strategies used to manage children exposed to long-term opioids are extrapolated from adult literature. Opioid consumption during the perioperative period is more than three times that observed in patients not taking chronic opioids. A sparing use of opioids in the perioperative period results in both poor pain management and withdrawal phenomena. The child's pre-existing opioid requirement should be maintained, and acute pain associated with operative procedures should be managed with additional analgesia. This usually comprises short-acting opioids, regional or local anesthesia, and adjuvant therapies. Long-acting opioids, transdermal opioid patches, and implantable pumps can be used to maintain the regular opioid requirement. Intravenous infusion, nurse controlled analgesia, patient-controlled analgesia, or oral formulations are invaluable for supplemental requirements postoperatively. Effective management requires more than simply increasing opioid dose during this time. Collaboration of the child, family, and all teams involved is necessary. While chronic pain or palliative care teams and other staff experienced with the care of children suffering chronic pain may have helpful input, many pediatric hospitals do not have chronic pain teams, and many patients receiving long-term opioids are not palliative. Acute pain services are appropriate to deal with those on long-term opioids in the perioperative setting and do so successfully in many centers. Staff caring for such children in the perioperative period should be aware of the challenges these children face and be educated before surgery about strategies for postoperative management and discharge planning.

[Postoperative pain management for patients who are long-term users of opioid]

Pain is one of the most common reasons for seeking medical care and the frequency of prescription of opioid analgesics by both primary care physicians and specialists has increased. It is therefore unsurprising that many patients with chronic pain who must undergo scheduled or emergency surgery will be on long-term medication, including opioids. Managing postoperative pain, even with high doses of drugs, seems to be more difficult in regular users of such analgesics, possibly because of an apparent association of opioid use with increased tolerance and hyperalgesia. Postoperative pain relief should be carefully tailored in these cases by means of a management plan worked out along with the patient. Adjuvants may be particularly useful; the most thoroughly studied adjuvants are nonsteroidal anti-inflammatory drugs and ketamine. Regional anesthesia offers a particularly attractive approach when long-term users of opioids must undergo surgery.

Postoperative pain patterns in chronic pain patients: a pilot study

OBJECTIVE

This exploratory investigation compared patterns of postoperative pain over 6 days in normal patients recovering from surgery with those of patients using opioid medications for chronic pain. It tested the following hypotheses: 1) Chronic pain patients have a different pattern of postoperative pain than normals; 2) Women have a different pattern of postoperative pain resolution than men.

PATIENTS

Normal (N = 96) and chronic pain (N = 42) patients undergoing surgery served as subjects.

DESIGN

The study employed a linear mixed effects model to compare repeated measures of pain in the two patient groups.

OUTCOME MEASURES

Patients rated pain daily following surgery over 6 days. Each patient's pain pattern is a linear trend having an intercept (initial pain level) and a slope (rate of pain change over days).

RESULTS

The chronic pain patients initially reported a higher mean pain level, and they differed from normal patients in their average postoperative pain patterns (P < 0.001), as did men and women (P = 0.039). Whereas normals decreased in pain report over the 6 days of recovery at an average rate of -0.35 units per day, chronic pain patients changed at an average rate of only -0.06 units per day (P < 0.001). Women began at day 0 with greater average pain than men (6.15 vs 5.16, P = 0.029) but resolved their pain more rapidly (-0.291 points per day vs -0.118 points per day, P = 0.017).

CONCLUSIONS

Surgical patients who have chronic pain and use opioid medications for that pain have more postoperative pain than normals and resolve that pain more slowly.

Perioperative management of chronic pain patients with opioid dependency

PURPOSE OF REVIEW

In this article, we discuss the perioperative anesthesia and pain management of patients with chronic pain receiving chronic opioid administration. In our practice we may expect to be confronted with opioid-dependent patients in routine anesthesia practice and should acquire specific knowledge and skills to effectively manage the perioperative and acute pain management issues that arise.

RECENT FINDINGS

The number of patients treated chronically with opioids has increased steadily over the past decade; currently about 10% of all chronic-pain patients are treated with opioids. As these patients are no longer confined to terminally ill cancer patients, growing numbers of these patients are facing surgical interventions.

SUMMARY

In our clinical practice, we should employ multimodal pain management therapy by using an around-the-clock regimen of nonsteroidal anti-inflammatory drugs, cyclooxygenase-2 inhibitors, acetaminophen, and regional blockade. Dosing regimens should be individualized to optimize efficacy while minimizing the risk of adverse events.