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.

Frequency, Outcomes, and Associated Factors for Opioid-Induced Neurotoxicity in Patients with Advanced Cancer Receiving Opioids in Inpatient Palliative Care

Context: Opioid-induced neurotoxicity (OIN) is an underdiagnosed yet distressing symptom in palliative care patients receiving opioids. However, there have been only a limited number of studies on OIN. Objectives: Our aim was to determine the frequency of and risk factors for OIN in patients receiving opioids during inpatient palliative care. Methods: We randomly selected 390 of 3014 eligible patients who had undergone palliative care consultations from January 2014 to December 2014. Delirium, drowsiness, hallucinations, myoclonus, seizures, and hyperalgesia were defined as OIN and were recorded. The other 10 common symptoms in cancer patients were assessed using the Edmonton Symptom Assessment Scale (ESAS). Patient demographics, morphine equivalent daily dose (MEDD), comorbidities, OIN management, and overall survival (OS) duration were also assessed. The associations between the incidence of OIN and MEDD, the other 10 symptoms, and OS were analyzed. Results: Fifty-seven (15%) patients had OIN. The most common symptom was delirium (n = 27). On multivariate analysis, a high MEDD (p = 0.020), high ESAS pain score (p = 0.043), drowsiness (p = 0.007), and a poor appetite (p = 0.014) were significantly associated with OIN. OIN was not significantly associated with a shorter OS duration (p = 0.80). Conclusions: OIN was seen in 15% of patients receiving opioids as part of inpatient palliative care. Although OIN was not associated with OS, routine monitoring is especially needed in cancer patients.

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.

Pain in the ICU: a psychiatric perspective

Pain is abundant in the intensive care unit (ICU). Successful analgesia demands a comprehensive appreciation for the etiologies of pain, vigilant clinical assessment, and personalized treatments. For the critically ill, frequent threats to mental and bodily integrity magnify the experience of pain, challenging clinicians to respond swiftly and thoughtfully. Because pain is difficult to predict and physiologic correlates are not specific, self-report remains the gold standard assessment. When communication is limited by intubation or cognitive deficits, behavioral pain scales prove useful. Patient-tailored analgesia aspires to mitigate suffering while optimizing alertness and cognitive capacity. Mindfulness of the neuropsychiatric features of pain helps the ICU clinician to clarify limits of traditional analgesia and identify alternative approaches to care. Armed with empirical data and clinical practice recommendations to better conceptualize, identify, and treat pain and its neuropsychiatric comorbidities, the authors (psychiatric consultants, by trade) reinforce holistic approaches to pain management in the ICU. After all, without attempts to understand and relieve suffering on all fronts, pain will remain undertreated.

Clinical guidelines for the use of chronic opioid therapy in chronic noncancer pain

Use of chronic opioid therapy for chronic noncancer pain has increased substantially. The American Pain Society and the American Academy of Pain Medicine commissioned a systematic review of the evidence on chronic opioid therapy for chronic noncancer pain and convened a multidisciplinary expert panel to review the evidence and formulate recommendations. Although evidence is limited, the expert panel concluded that chronic opioid therapy can be an effective therapy for carefully selected and monitored patients with chronic noncancer pain. However, opioids are also associated with potentially serious harms, including opioid-related adverse effects and outcomes related to the abuse potential of opioids. The recommendations presented in this document provide guidance on patient selection and risk stratification; informed consent and opioid management plans; initiation and titration of chronic opioid therapy; use of methadone; monitoring of patients on chronic opioid therapy; dose escalations, high-dose opioid therapy, opioid rotation, and indications for discontinuation of therapy; prevention and management of opioid-related adverse effects; driving and work safety; identifying a medical home and when to obtain consultation; management of breakthrough pain; chronic opioid therapy in pregnancy; and opioid-related policies.

PERSPECTIVE

Safe and effective chronic opioid therapy for chronic noncancer pain requires clinical skills and knowledge in both the principles of opioid prescribing and on the assessment and management of risks associated with opioid abuse, addiction, and diversion. Although evidence is limited in many areas related to use of opioids for chronic noncancer pain, this guideline provides recommendations developed by a multidisciplinary expert panel after a systematic review of the evidence.

Use of Hydromorphone (Dilaudid) and Morphine for Patients With Hepatic and Renal Impairment

Management of pain in the elderly is very challenging. First, the compromised ability to perceive pain because of loss of sensory neurons and other comorbid conditions such as dementia and degenerative joint diseases make the assessment of severity source and localization of pain very difficult. Second, decrease in the renal and hepatic blood flow and decrease in the hepatic and renal mass, along with decrease in volume of distribution caused by decrease in total body water and hypoproteinemia, makes the elderly very sensitive to adverse effects of different pain medicines. Third, many elderly patients have comorbid conditions causing impaired hepatic and renal impairment. In this article, we review the role of 2 more commonly used opiates, morphine and hydromorphone, in elderly patients with hepatic and renal impairment.

Pain assessment and management

Assessment and management of pain is crucial to the success of any program of care for dying patients and their families. With appropriate assessment and management, often using home health or hospice teams, pain can be controlled in more than 90% of patients. This article focuses on the symptomatic care of patients who are dying. The legal and regulatory issues that may inhibit delivery of adequate opioid therapy are also reviewed.

Oral Ketamine in Hepatocellular Carcinoma

Ketamine, an NMDA antagonist, has been used in pain treatment for a number of years. Recent reports have suggested its utility in a variety of pain states including post-herpetic neuralgia [1], cancer [2], and postoperative pain [5]. While a variety of neuropsychologic side effects are observed with parenteral ketamine, in oral use these side effects have been less pronounced [2,3]. We report a patient with severe hepatic disease who developed hallucinations following a 75-mg oral dose of ketamine for treatment of severe cancer pain unresponsive to morphine.

Advances in pain management for older adult patients

Management of pain is crucial to the success of any program of care and support for dying patients and their families. Pain can be controlled in more than 90% of older adults. Components of an effective program include comprehensive, repeated pain assessment; detection and treatment of complicating medical and psychological disorders (e.g., delirium); spiritual concerns; and the judicious use of nonpharmacologic and pharmacologic therapies, radiation, and radiopharmaceuticals. Strategies that enable clinicians to prevent and treat the expected complications of nonsteroidal anti-inflammatory and opioid therapies are reviewed. Strategies to change opioid agents or routes to minimize opioid-induced side effects and to provide effective pain relief as death nears are presented.