Morphine and hydromorphone-induced hyperalgesia in a hospice patient

Opioid-induced Neurotoxicity in Patients with Cancer Pain

OPINION STATEMENT

Opioid-induced neurotoxicity (OINT) is a neuropsychiatric syndrome observed with opioid therapy. The mechanism of OINT is thought to be multifactorial, and many risk factors may facilitate its development. If symptoms of OINT are seen, the prescriber should consider hydration, discontinuation of the offending opioid drug, or switching of opioid medication, or the use of some adjuvants. Multiple factors like inter- and intraindividual differences in opioid pharmacology may influence the accuracy of dose calculations for opioid switching. Experience and clinical judgment in a specialistic palliative care setting should be used and individual patient characteristics considered when applying any conversion table.

Palliative Extubation: A Discussion of Practices and Considerations

Palliative extubation (PE), also known as compassionate extubation, is a common event in the critical care setting and an important aspect of end-of-life care.1 In a PE, mechanical ventilation is discontinued. Its goal is to honor the patient's preferences, optimize comfort, and allow a natural death when medical interventions, including maintenance of ventilatory support, are not achieving desired outcomes. If not done effectively, PE can cause unintended physical, emotional, psychosocial, or other stress for patients, families, and healthcare staff. Studies show that PE is done with much variability across the globe, and there is limited evidence of best practice. Nevertheless, the practice of PE increased during the coronavirus disease 2019 pandemic due to the surge of dying mechanically ventilated patients. Thus, the importance of effectively conducting a PE has never been more crucial. Some studies have provided guidelines for the process of PE. However, our goal is to provide a comprehensive review of issues to consider before, during, and after a PE. This paper highlights the core palliative skills of communication, planning, symptom assessment and management, and debriefing. Our aim is to better prepare healthcare workers to provide quality palliative care during PEs, most especially when facing future pandemics.

Opioid-induced Hyperalgesia in Patients With Chronic Pain: A Systematic Review of Published Cases

INTRODUCTION

Opioid-induced hyperalgesia (OIH) remains an issue in patients with chronic pain. Multiple cases of OIH in patients with chronic pain exposed to opioids have been reported worldwide. The objective of this systematic review was to summarize the evidence of OIH from clinical reports.

METHODS

We searched the PubMed, Cochrane, EMBASE, and LILACS databases for case reports and case series of OIH published up to December 2020, with the aim to summarize the evidence for OIH in patients with chronic pain from clinical reports and to discuss issues relevant to the clinical diagnosis and management of OIH.

RESULTS

We retrieved and reviewed 41 articles describing 72 cases. Clinical features of OIH were observed in patients of both sexes, all ages, and with various types of pain treated with different classes of opioids. OIH was reported at all doses, but most published studies reported a pattern of OIH following treatment with very high daily doses of opioids (median oral morphine equivalent dose of 850 mg). OIH was diagnosed clinically in all cases. Three different strategies for OIH management were described: opioid rotation, opioid cessation, and the use of adjuvant pharmacotherapies. All had statistically similar success rates for OIH treatment: 72%, 57%, and 79%, respectively. The decrease in pain was achieved rapidly (mean: 8 d; range: 1 to 28 d). Adjuvant therapies resulted in the largest decrease in dose. Ketamine and dexmedetomidine were the most widely used adjuvant drugs.

CONCLUSION

The key finding is that clinical symptoms of OIH can be resolved when this condition is diagnosed and managed.

Pearls for opioid use in seriously ill patients

Opioids are often the foundation of pain management in seriously ill patients. Unfortunately, even experienced providers carry with them information that they consider "fact", when this information is not based on scientific evidence, but on "myth". Several topics were elicited based on common beliefs and misconceptions in clinical practice. These were identified via a survey of pharmacist pain and palliative care providers. Pearls from these topics were chosen that were based on evidence and would have the greatest bearing on clinical practice. The pearls address topics such as not using opioids as first-line analgesics for all types of pain, opioid-induced hyperalgesia, opioid risk management in cancer patients, use of buprenorphine in hospice and palliative care settings and use of naloxone in seriously ill patients. The pearls are supported by clinical evidence extracted from several references. They are intended to make readers give thought to opioid therapy which is strictly evidence-based, and not historical or anecdote-based. Practical recommendations are provided to give readers a starting point to base clinical decisions going forward. Readers may discover that "facts" they once learned about opioid use in seriously ill patients are actually "myths" that are a figment of the past.

Subcutaneous or intravenous opioid administration by patient-controlled analgesia in cancer pain: a systematic literature review

CONTEXT

Opioids administered by various routes are a mainstay of tumour-related pain management. Subcutaneous or intravenous patient-controlled analgesia (PCA) with opioids is an appropriate and safe form of treatment for postoperative pain but studies on this form of administration are sparse in the setting of cancer pain despite widespread use.

OBJECTIVE

To evaluate the published studies on opioids administered by subcutaneous and intravenous patient-controlled analgesia for patients with cancer pain.

METHODS

Articles were identified from the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 7, 2016), PubMed (Medline; 1975 to 2016) and EMBASE (1974 to 2016). Additional reports were identified from the reference lists of retrieved papers. Studies based on original data with a focus on intravenous or subcutaneous PCA administration of opioids in patients suffering from cancer-related pain were selected. The language was restricted to Dutch, English or German. Predefined information was extracted depending on the topic.

RESULTS

Fifty studies published since 1980 met the inclusion criteria. A wide range of study designs, study quality and research objectives were observed. The studies indicated use of standard or by proxy PCA in the inpatient and outpatient setting were safe and useful while significant adverse effects were rarely observed.

CONCLUSION

This systematic review of the current evidence suggests PCA can be appropriately used in a wide range of clinical situations.

Evidence for Neurotoxicity Due to Morphine or Hydromorphone Use in Renal Impairment: A Systematic Review

BACKGROUND

Opioids are the mainstay of pain control for patients with chronic pain. Often, opioids with reported active metabolites, such as morphine and hydromorphone, are thought to increase the risk of neurotoxicity in renal impairment.

OBJECTIVES

To identify and assess the quality of evidence for neurotoxic effects in patients with renal impairment receiving morphine or hydromorphone.

METHODS

Systematic searches were conducted of the following databases from inception to December 2015: MEDLINE, CINAHL, EMBASE, in addition to hand-searching relevant review articles' citations. Studies were included if they reported neurotoxic effects of either morphine or hydromorphone for chronic or malignant pain in patients with renal impairment. Review articles and case reports were excluded. Narrative review was undertaken. The Grading of Recommendations, Assessment, Development and Evaluation approach was used to assess study quality.

RESULTS

Six original articles, three prospective and three retrospective studies were identified and assessed. No relevant randomized clinical trials were identified.

CONCLUSIONS

Although morphine and hydromorphone use may be associated with neurotoxic effects in patients with renal impairment, current evidence consists of very low-quality studies with conflicting findings. Clinicians may consider using either morphine or hydromorphone in mild-to-moderate renal impairment, while closely monitoring for neurotoxic effects, particularly when used in high doses and for extended duration.

Targeting Opioid-Induced Hyperalgesia in Clinical Treatment: Neurobiological Considerations

Opioid analgesics have become a cornerstone in the treatment of moderate to severe pain, resulting in a steady rise of opioid prescriptions. Subsequently, there has been a striking increase in the number of opioid-dependent individuals, opioid-related overdoses, and fatalities. Clinical use of opioids is further complicated by an increasingly deleterious profile of side effects beyond addiction, including tolerance and opioid-induced hyperalgesia (OIH), where OIH is defined as an increased sensitivity to already painful stimuli. This paradoxical state of increased nociception results from acute and long-term exposure to opioids, and appears to develop in a substantial subset of patients using opioids. Recently, there has been considerable interest in developing an efficacious treatment regimen for acute and chronic pain. However, there are currently no well-established treatments for OIH. Several substrates have emerged as potential modulators of OIH, including the N-methyl-D-aspartate and γ-aminobutyric acid receptors, and most notably, the innate neuroimmune system. This review summarizes the neurobiology of OIH in the context of clinical treatment; specifically, we review evidence for several pathways that show promise for the treatment of pain going forward, as prospective adjuvants to opioid analgesics. Overall, we suggest that this paradoxical state be considered an additional target of clinical treatment for chronic pain.

Opioid-induced hyperalgesia in chronic pain patients and the mitigating effects of gabapentin

Chronic pain patients receiving opioid drugs are at risk for opioid-induced hyperalgesia (OIH), wherein opioid pain medication leads to a paradoxical pain state. OIH involves central sensitization of primary and secondary afferent neurons in the dorsal horn and dorsal root ganglion, similar to neuropathic pain. Gabapentin, a gamma-aminobutyric acid (GABA) analog anticonvulsant used to treat neuropathic pain, has been shown in animal models to reduce fentanyl hyperalgesia without compromising analgesic effect. Chronic pain patients have also exhibited lower opioid consumption and improved pain response when given gabapentin. However, few human studies investigating gabapentin use in OIH have been performed in recent years. In this review, we discuss the potential mechanisms that underlie OIH and provide a critical overview of interventional therapeutic strategies, especially the clinically-successful drug gabapentin, which may reduce OIH.

Postoperative pain management in patients with chronic kidney disease

Chronic kidney disease (CKD) is a health care problem with increasing prevalence worldwide. Pain management represents one of the challenges in providing perioperative care for this group of patients. Physicians from different specialties may be involved in pain management of CKD patients, especially in advanced stages. It is important to understand the clinical staging of kidney function in CKD patients as the pharmacotherapeutic pain management strategies change as kidney function becomes progressively impaired. Special emphasis should be placed on dose adjustment of certain analgesics as well as prevention of further deterioration of renal function that could be induced by certain classes of analgesics. Chronic pain is a common finding in CKD patients which may be caused by the primary disease that led to kidney damage or can be a direct result of CKD and hemodialysis. The presence of chronic pain in some of the CKD patients makes postoperative pain management in these patients more challenging. This review focuses on the plans and challenges of postoperative pain management for patient at different stages of CKD undergoing surgical intervention to provide optimum pain control for this patient population. Further clinical studies are required to address the optimal medication regimen for postoperative pain management in the different stages of CKD.