The panorama of opioid-related cognitive dysfunction in patients with cancer: a critical literature appraisal

Extracellular vesicles-Mediators of opioid use disorder?

Opioid use disorder (OUD) is a growing health emergency in the United States leading to an epidemic of overdose deaths. OUD is recognized as an addictive brain disorder resulting in psychological, cognitive and behavioural dysfunction. These observed clinical dysfunctions are a result of cellular changes that occur in the brain. Derangements in inflammation, neurogenesis and synaptic plasticity are observed in the brains of OUD patients. The mechanisms of these derangements are unclear; however, extracellular vesicles (EVs), membrane bound particles containing protein, nucleotides and lipids are currently being investigated as agents that invoke these cellular changes. The primary function of EVs is to facilitate intercellular communication by transfer of cargo (protein, nucleotides and lipids) between cells; however, changes in this cargo have been observed in models of OUD suggesting that EVs may be agents promoting the observed cellular derangements. This review summarizes evidence that altered cargo of EVs, specifically protein and miRNA, in models of OUD promote impairments in neurons, astrocytes and microglial cells. These findings support the premise that opioids alter EVs to detrimentally affect neuro-cellular function resulting in the observed addictive, psychological and neurocognitive deficits in OUD patients.

Delirium in oncological palliative care and clinical cardiology units: A comparative analysis

OBJECTIVE

The aim of this study was to compare the sociodemographic and clinical characteristics of delirium in patients treated in a clinical cardiology unit (CCU) and an oncological palliative care unit (OPCU) at a high-complexity institution.

CONTEXT

Delirium is a neuropsychiatric syndrome with multicausal etiology, associated with increased morbidity and mortality.

METHOD

This was a cross-sectional, analytical observational study. CCU and OPCU patients were evaluated for 480 days. The diagnosis was made according to DSM-V. Sociodemographic characteristics, the Karnofsky index, and the Charlson index were evaluated. Possible etiologies were verified. Severity was assessed with the Delirium Severity Scale (DRS-R98).

RESULTS

A total of 1,986 patients were evaluated, 205 were eligible, and 110 were included in the study (CCU: 61, OPCU: 49). Delirium prevalence was 11.35% in the CCU and 9.87% in the OPCU. CCU patients were 12 years older (p < 0.03) and a history of dementia (41 vs. 8.2%; p < 0.001). Organ failure was the most frequent etiology of delirium in the CCU (41.0%), and in the OPCU, the etiologies were neoplasms (28.6%), side effect of medication (22.4%), and infections (2.5%). Differences were found in the clinical characteristics of delirium evaluated by DRS-R98, with the condition being more severe and with a higher frequency of psychotic symptoms in OPCU patients.

CONCLUSION

Delirium was a common condition in hospitalized patients in the CCU and the OPCU. The clinical characteristics were similar in both groups; however, significant differences were found in OPCU patients in terms of age, personal history of dementia, and opioid use, as well as the severity of delirium and a greater association with psychotic symptoms. These findings have implications for the early implementation of diagnostic and therapeutic strategies.

Transcriptome Analysis of the Mouse Medial Prefrontal Cortex in a Chronic Constriction Injury Model

The medial prefrontal cortex (mPFC) is critical for both the sensory and emotional/cognitive components of pain. However, the underlying mechanism remains largely unknown. Here, we examined changes in the transcriptomic profiles in the mPFC of mice with chronic pain using RNA sequencing (RNA-seq) technology. A mouse model of peripheral neuropathic pain was established via chronic constriction injury (CCI) of the sciatic nerve. CCI mice developed sustained mechanical allodynia and thermal hyperalgesia, as well as cognitive impairment four weeks after surgery. RNA-seq was conducted 4 weeks after CCI surgery. Compared with contral group, RNA-seq identified a total 309 and 222 differentially expressed genes (DEGs) in the ipsilateral and contralateral mPFC of CCI model mice, respectively. GO analysis indicated that the functions of these genes were mainly enriched in immune- and inflammation-related processes such as interferon-gamma production and cytokine secretion. KEGG analysis further showed the enrichment of genes involved in the neuroactive ligand-receptor interaction signaling pathway and Parkinson disease pathway that have been reported to be importantly involved in chronic neuralgia and cognitive dysfunction. Our study may provide insights into the possible mechanisms underlying neuropathic pain and pain-related comorbidities.

Non-invasive brain stimulation and pain neuroscience education in the cognitive-affective treatment of chronic low back pain: Evidence and future directions

Chronic low back pain (CLBP) is among the leading causes of disability worldwide. Beyond the physical and functional limitations, people's beliefs, cognitions, and perceptions of their pain can negatively influence their prognosis. Altered cognitive and affective behaviors, such as pain catastrophizing and kinesiophobia, are correlated with changes in the brain and share a dynamic and bidirectional relationship. Similarly, in the presence of persistent pain, attentional control mechanisms, which serve to organize relevant task information are impaired. These deficits demonstrate that pain may be a predominant focus of attentional resources, leaving limited reserve for other cognitively demanding tasks. Cognitive dysfunction may limit one's capacity to evaluate, interpret, and revise the maladaptive thoughts and behaviors associated with catastrophizing and fear. As such, interventions targeting the brain and resultant behaviors are compelling. Pain neuroscience education (PNE), a cognitive intervention used to reconceptualize a person's pain experiences, has been shown to reduce the effects of pain catastrophizing and kinesiophobia. However, cognitive deficits associated with chronic pain may impact the efficacy of such interventions. Non-invasive brain stimulation (NIBS), such as transcranial direct current stimulation (tDCS) or repetitive transcranial magnetic stimulation (rTMS) has been shown to be effective in the treatment of anxiety, depression, and pain. In addition, as with the treatment of most physical and psychological diagnoses, an active multimodal approach is considered to be optimal. Therefore, combining the neuromodulatory effects of NIBS with a cognitive intervention such as PNE could be promising. This review highlights the cognitive-affective deficits associated with CLBP while focusing on current evidence for cognition-based therapies and NIBS.

Do Cognitively Impaired Elderly Patients with Cancer Respond Differently on Self-reported Symptom Scores? A 5-Year Retrospective Analysis

Objectives:

An increasing number of elderly subjects with cancer were admitted to the palliative care unit and they have suffered both distressing symptoms and cognitive impairment. We aim to identify the prevalence of cognitive impairment among elderly cancer patients receiving in-patient palliative care and to examine any difference between patients with cognitive impairment on self-reported symptoms.

Materials and Methods:

Subjects’ age ≥65 admitted to a palliative care unit from 01 September 2015 to 31 August 2020 was included in the study. Exclusion criteria were those with an impaired conscious state, severe cognitive impairment, or language problems that were non-communicable. Variables collected included baseline demographics, cancer diagnosis, cancer stage, mobility state using the modified Barthel index (mBI), and performance status as measured by the palliative performance scale. Cognitive impairment was defined by abbreviated mental test ≤6. Self-reported symptoms scales were measured by the Chinese version of MD Anderson Symptom Inventory and EORTC QLQ C-30 (European Organisation for Research and Treatment of Cancer, Quality of Life Core Questionnaire 30).

Results:

Nine hundred and ninety-one subjects with 1174 admissions were retrieved. Eight hundred and seventy-three admission episodes were included in this study. Three hundred and eight (35%) have cognitive impairment. Cognitively impaired subjects were older, showed worse physical function and performance status, and more often residing in old age homes. Independent predictors of cognitive impairment were age (OR 1.09), mBI (OR 0.96), chair/bed bound state (OR 1.79), and presence of brain metastasis (OR 2.63). They reported lower scores in pain (P < 0.001), distress (P < 0.001), sleep disturbance (P < 0.001) and nausea and vomiting (P = 0.012) in the self-reported symptoms scale.

Conclusion:

Elderly cancer patients with cognitive impairment were older with poorer performance status. They have reported a lower level of pain, distress, and sleep disturbance. Clinicians should be alerted to this phenomenon to tackle the unmet concomitant symptoms.

Combining subjective and objective appraisals of cognitive dysfunction in patients with cancer: a deeper understanding of meaning and impact on suffering?

PURPOSE

Patients with advanced cancer often experience cognitive dysfunction, which may influence decision making, self-perception, and existential well-being. However, there is little evidence regarding this issue. This study analysed associations between objective neuropsychological measures and patients' self-report of cognitive dysfunction interfering with everyday life, general well-being, and sense of existential value.

METHODS

A mixed method study assessed 13 adult patients with advanced cancer with validated neuropsychological tests, which assessed sustained attention, psychomotor speed, memory/attention, mental flexibility, and a measure of global cognitive function. These were followed by semi-structured interviews focusing on subjective experiences of cognitive dysfunction. Agreement between subjective and objective measures were analysed by Cohen's Kappa (k). Thematic analysis explored associations with cognitive deficits.

RESULTS

Poor cognitive performance on the neuropsychological tests was observed regarding sustained attention (n = 8), psychomotor speed (n = 1), memory/attention (n = 2), mental flexibility (n = 9), and global cognitive function (n = 3). Almost all patients (n = 12) had complaints of cognitive dysfunction. However, the agreement between the two assessments was weak (k ≤ 0.264). Cognitive dysfunction challenged the patients with regard to practice everyday life including their existential values related to meaning of life and well-being. Adjustment of the sense of living according to one's existential values and changes of self-perception were also related positively and negatively to existential well-being.

CONCLUSION

Despite the weak agreement between objective and subjective measures of cognitive function, many of the patients reported experiences of cognitive dysfunction that had an impact on their daily life and existential well-being, adding to the suffering experienced.

Astrocytes & Astrocyte derived Extracellular Vesicles in Morphine Induced Amyloidopathy: Implications for Cognitive Deficits in Opiate Abusers

While opiates like morphine play a major role in the pharmacotherapy for the control of pain associated with various diseases, paradoxically, their long-term use is associated with cognitive impairments. Furthermore, morphine administration has been shown to result in neuronal synaptodendritic injury in rodent brains, leading to neurodegeneration. We recently reported the role of astrocytes as contributors of amyloidosis associated with HIV-associated neurological disorders. Herein we hypothesize that morphine could induce astrocytic amyloidosis, which, in turn, could be disseminated to various regions in the brain by astrocyte-derived EVs (ADEVs). In this study we demonstrate brain region-specific up-regulation of astrocytic amyloids in morphine dependendent rhesus macaques. In addition, herein we also demonstrate increased expression of β-site cleaving enzyme (BACE1), APP, and Aβ in human primary astrocytes (HPAs) exposed to morphine. Mechanisms involved in this process included the up-regulation of hypoxia-inducible factor (HIF-1α), its translocation and binding to the promoter of BACE1, leading to increased BACE1 activity and, generation of Aβ 1-42. Gene silencing approaches confirmed the regulatory role of HIF-1α in BACE1 mediated amyloidosis leading to astrocyte activation and neuroinflammation. We next sought to assess whether morphine-stimulated ADEVs could carry amyloid cargoes. Results showed that morphine exposure induced the release of morphine-ADEVs, carrying amyloids. Interestingly, silencing HIF-1α in astrocytes not only reduced the numbers of ADEV released, but also the packaging of amyloid cargos in the ADEVs. These findings were further validated in brain derived EVs (BEVs) isolated from macaques, wherein it was shown that BEVs from morphine-dependent macaques, carried varieties of amyloid cargoes including the cytokine IL-1β. This is the first report implicating the role of HIF-1α-BACE1 axis in morphine-mediated induction of astrocytic amyloidosis, leading, in turn, to neuroinflammation and release of the amyloid cargoes via ADEVs. These findings set the groundwork for the future development of therapeutic strategies for targeting cognitive deficits in chronic opiate users.

The effect of opioids on the cognitive function of older adults: results from the Personality and Total Health through life study

BACKGROUND

chronic pain, a common complaint among older adults, affects physical and mental well-being. While opioid use for pain management has increased over the years, pain management in older adults remains challenging, due to potential severe adverse effects of opioids in this population.

OBJECTIVE

we examined the association between opioid use, and changes in cognitive function of older adults.

DESIGN

prospective study.

SETTING

community dwelling older adults.

SUBJECTS

study population consisted of 2,222 individuals aged 65-69 years at baseline from the Personality and Total Health Through Life Study in Australia.

METHODS

medication data were obtained from the Pharmaceutical Benefits Scheme. Cognitive measures were obtained from neuropsychological battery assessment. Opioid exposure was quantified as Total Morphine Equivalent Dose (MED). The association between change in cognitive function between Wave 2 and Wave 3, and cumulative opioid use was assessed through generalized linear models.

RESULTS

cumulative opioid exposure exceeding total MED of 2,940 was significantly associated with poorer performance in the Mini Mental State Examination (MMSE). Compared with those not on opioids, individuals exposed to opioids resulting in cumulative total MED of greater than 2,940 had significantly lower scores in the MMSE (Model 1: β = -0.34, Model 2: β = -0.35 and Model 3: β = -0.39, P < 0.01). Performance in other cognitive assessments was not associated with opioid use.

CONCLUSION

prolonged opioid use in older adults can affect cognitive function, further encouraging the need for alternative pain management strategies in this population. Pain management options should not adversely affect healthy ageing trajectories and cognitive health.

Cognition and Pain: A Review

Cognition is defined as the brain's ability to acquire, process, store, and retrieve information. Pain has been described as an unpleasant sensory or emotional experience, and for experiencing pain consciously, cognitive processing becomes imperative. Moreover, evaluation of pain strongly depends on cognition as it requires learning and recall of previous experiences. There could be a possible close link between neural systems involved in cognition and pain processing, and studies have reported an association between pain and cognitive impairment. In this narrative review, we explore the available evidence that has investigated cognitive changes associated with pain. We also examine the anatomical, biochemical, and molecular association of pain and neuro-cognition. Additionally, we focus on the cognitive impairment caused by analgesic medications. There is a need to improve our understanding of pathophysiology and cognitive impairment mechanisms associated with chronic pain and its treatment. This area provides a diverse opportunity for grounding future research, aiding institution of timely interventions to prevent chronic pain and associated cognitive decline, ultimately improving patient care.

Opioid-Induced Hearing Loss and Neonatal Abstinence Syndrome: Clinical Considerations for Audiologists and Recommendations for Future Research

Purpose Over the last two decades, the number of Americans misusing opioids has reached epidemic levels. With such drastic increases in opioid misuse, audiologists are more likely to have patients with opioid-induced hearing loss or neonatal abstinence syndrome (NAS) than in previous years. More attention is needed on how these increases might influence clinical practice and such a discussion could be useful for audiologists. The goal of this article, therefore, is to summarize what is currently known regarding the relationship between opioid misuse and audiology to help guide hearing health care providers (with a particular focus on opioid-induced hearing loss and NAS). This article (a) summarizes the overlap in opioid misuse and hearing loss populations, (b) describes the evidence linking opioid misuse to hearing loss, (c) discusses clinical implications that opioid-induced hearing loss and NAS have for practicing audiologists, and (d) recommends directions for future audiological research on opioid-induced hearing loss and NAS. Conclusions There is considerable overlap between populations at-risk for hearing loss and opioid misuse. Additionally, compelling evidence exists linking opioid misuse to hearing loss, but the specific causal mechanisms remain unclear, indicating a need for additional research. This article attempts to fill a gap in the audiological literature and has the potential to serve as a guide for hearing health care providers to make more informed clinical decisions regarding patients with opioid-induced hearing loss and NAS. Clinicians may wish to consider the concerns raised in this article before intervening with such concerns, especially in the absence of best practice protocols.

Opioid and neuroHIV Comorbidity - Current and Future Perspectives

With the current national opioid crisis, it is critical to examine the mechanisms underlying pathophysiologic interactions between human immunodeficiency virus (HIV) and opioids in the central nervous system (CNS). Recent advances in experimental models, methodology, and our understanding of disease processes at the molecular and cellular levels reveal opioid-HIV interactions with increasing clarity. However, despite the substantial new insight, the unique impact of opioids on the severity, progression, and prognosis of neuroHIV and HIV-associated neurocognitive disorders (HAND) are not fully understood. In this review, we explore, in detail, what is currently known about mechanisms underlying opioid interactions with HIV, with emphasis on individual HIV-1-expressed gene products at the molecular, cellular and systems levels. Furthermore, we review preclinical and clinical studies with a focus on key considerations when addressing questions of whether opioid-HIV interactive pathogenesis results in unique structural or functional deficits not seen with either disease alone. These considerations include, understanding the combined consequences of HIV-1 genetic variants, host variants, and μ-opioid receptor (MOR) and HIV chemokine co-receptor interactions on the comorbidity. Lastly, we present topics that need to be considered in the future to better understand the unique contributions of opioids to the pathophysiology of neuroHIV.

Graphical Abstract

Mild to Moderate Cognitive Impairment Does Not Affect the Ability to Self-Report Important Symptoms in Patients With Cancer: A Prospective Longitudinal Multinational Study (EPCCS)

CONTEXT

Patients with advanced cancer commonly suffer from both distressing symptoms and cognitive impairment, but the effect of cognitive impairment on the reliability and validity of symptom self-report is unknown.

OBJECTIVES

To evaluate the reliability and validity of symptom self-report in cancer outpatients with and without mild to moderate cognitive impairment.

METHODS

This was an analysis of the longitudinal European Palliative Care Cancer Symptom study of adults with incurable cancer in specialized palliative care (30 centers across 12 countries). Patients who could not comply with the study because of severe cognitive impairment were excluded. Cognitive status on the Mini-Mental State Examination short version and nine symptoms (pain, tiredness, drowsiness, nausea, appetite, breathlessness, depression, anxiety, and well-being) using the revised Edmonton Symptom Assessment System were self-reported at baseline and one-month follow-up. Reliability was analyzed using intraclass correlation coefficients and validity using regression of each symptom with health-related quality of life (HrQoL) measured with European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 15 for Palliative Care.

RESULTS

A total of 1047 patients were included: mean age of 62.9 years; 54.4% women; main cancer types were of digestive organs (26.6%), breast (21.6%), and lungs (21.2%). Cognitive impairment was present in 181 (17.3%) at baseline and associated with worse self-reported tiredness, drowsiness, appetite, and depression. Reliability (intraclass correlation coefficient) and validity (associations with HrQoL) were similar between people with/without cognitive impairment across the nine symptoms, except breathlessness, which showed a weaker relation to HrQoL in patients with cognitive impairment. Findings were robust in sensitivity analyses and after controlling for potential confounders.

CONCLUSION

In advanced cancer, self-report of nine major symptoms was reliable and valid also in people with mild-to-moderate cognitive impairment.

TRIAL REGISTRATION

ClinicalTrials.gov database (NCT01362816).

Opioid Analgesics Adverse Effects: The Other Side of the Coin

BACKGROUND

Opioids are the cornerstone of the management of cancer pain. However, the development of adverse effects may compromise the opioid response. They include nausea and vomiting, constipation, drowsiness, sleep disorders, cognitive dysfunction, myoclonus, pruritus, dysuria, dependence and the development of aberrant behaviors, respiratory depression, and some endocrine responses.

METHODS

The goal of this paper is to identify the most common opioid-related adverse effects, their pathophysiology, and proposing the possible treatments. This narrative review will describe how these adverse effects may develop and how to prevent or to treat.

CONCLUSION

Intensity of adverse effects tend to decrease with continuous use. However, they may be persistent and may require symptomatic treatment or more complex treatment including alternative strategies for pain management.

Cognitive dysfunction in patients of rheumatoid arthritis

Rheumatoid Arthritis (RA) is a form of arthritis characterized by joint pain, stiffness, swelling and deformity. There has been plethora of researches in the area of rheumatoid arthritis which focused on immune system, genetic predisposition and newer treatment modalities. Researchers have also examined the cognitive decline, physical deficits and their interrelationship in patients with RA. Among several psychological aspects depression, anxiety and stress emerge as significant psychological co morbidity. RA is a multifactorial, chronic, inflammatory disease primarily affects physical functioning as well as psychological aspects. Pain, fatigue, duration of disease, disease activity and functional disability are very common in rheumatoid arthritis which is leading cause of psychological distress and functional disability. Various types of neuropsychological battery were used to assess the decline in specific areas like attention, executive functioning, visuo-spatial learning, verbal learning/memory etc. These functions were compared with other type of arthritis disease. Also, various other factors like depression, cardiovascular diseases, other systemic and chronic disease and concomitant drugs intake etc. also affected cognitive functioning in Rheumatoid Arthritis patients. The objective of this review was to identify and explore the rates and types of cognitive impairment in RA. This present review paper systematically examines and summarizes the cognition related decrement in arthritis patients. Multiple research articles between 1990 to 2018 were searched. These reviews were evaluated and synthesized using a narrative and descriptive approach.

The neurocognitive function change criteria after whole-brain radiation therapy for brain metastasis, in reference to health-related quality of life changes: a prospective observation study

BACKGROUND

We sought to construct the optimal neurocognitive function (NCF) change criteria sensitive to health-related quality of life (HR-QOL) in patients who have undergone whole-brain radiation therapy (WBRT) for brain metastasis.

METHODS

We categorized the patients by the changes of NCF into groups of improvement versus deterioration if at least one domain showed changes that exceeded the cut-off while other domains remained stable. The remaining patients were categorized as stable, and the patients who showed both significant improvement and deterioration were categorized as 'both.' We examined the clinical meaning of NCF changes using the cut-off values 1.0, 1.5, and 2.0 SD based on the percentage of patients whose HR-QOL changes were ≥ 10 points.

RESULTS

Baseline, 4-month and 8-month data were available in 78, 41 (compliance; 85%), and 29 (81%) patients, respectively. At 4 months, improvement/stable/deterioration/both was seen in 15%/12%/41%/32% of the patients when 1.0 SD was used; 19%/22%/37%/22% with 1.5 SD, and 17%/37%/37%/9% with 2.0 SD. The HR-QOL scores on the QLQ-C30 functional scale were significantly worse in the deterioration group versus the others with 1.0 SD (p = 0.013) and 1.5 SD (p = 0.015). With 1.5 SD, the HR-QOL scores on the QLQ-BN20 was significantly better in the improvement group versus the others (p = 0.033). However, when 'both' was included in 'improvement' or 'deterioration,' no significant difference in HR-QOL was detected.

CONCLUSIONS

The NCF cut-off of 1.5 SD and the exclusion of 'both' patients from the 'deterioration' and 'improvement' groups best reflects HR-QOL changes.

Balancing opioid analgesia with the risk of nonmedical opioid use in patients with cancer

The current opioid crisis has brought renewed attention and scrutiny to opioid prescriptions. When patients receiving opioid therapy for pain engage in nonmedical opioid use (NMOU) or diversion, untoward consequences can occur. New evidence suggests that patients with cancer might be at a higher risk of NMOU than was previously thought, but clinical evidence still supports the use of opioid analgesics as the gold standard to treat cancer-related pain, creating a dilemma in patient management. Clinicians are encouraged to adopt a universal precautions approach to patients with cancer receiving opioids, which includes screening all patients; discussing the risks, benefits, adverse effects and alternatives of opioid therapy; and providing education on safe use, storage and disposal. Use of urine drug tests, prescription drug monitoring programmes and close observation of behaviours related to opioid use help to ensure treatment adherence, detect NMOU and support therapeutic decision-making. These measures can optimize the risk-benefit ratio while supporting safe opioid use. In this Review, we examine the role of opioids in cancer pain, the risk of substance use disorder and methods to achieve the right balance between the two in order to ensure safe opioid use.

Brain metastases and treatment: multiplying cognitive toxicities

INTRODUCTION

Thirty per cent of cancer patients develop brain metastases, with multiple combination or sequential treatment modalities available, to treat systemic or central nervous system (CNS) disease. Most patients experience toxicities as a result of these treatments, of which cognitive impairment is one of the adverse events most commonly reported, causing major impairment of the patient's quality of life. Areas covered: This article reviews the role of cancer treatments in cognitive decline of patients with brain metastases: surgery, radiotherapy, chemotherapy, targeted therapies, immunotherapies and hormone therapy. Pathological and molecular mechanisms, as well as future directions for limiting cognitive toxicities are also presented. Other causes of cognitive impairment in this population are discussed in order to refine the benefit-risk balance of each treatment modality. Expert opinion: Cumulative cognitive toxicity should be taken into account, and tailored to the patient's cognitive risk in the light of the expected survival benefit. Standardization of cognitive assessment in this context is needed in order to better appreciate each treatment's responsibility in cognitive impairment, keeping in mind disease itself impacts cognition in this context.

Pain Management for Patients With Advanced Cancer in the Opioid Epidemic Era

Use of opioids for the treatment of pain is necessary for the majority of patients with advanced cancer, however its use has become challenging in the face of the opioid epidemic and the emerging evidence that patients with cancer are also at risk for nonmedical opioid use. This article proposes an assessment and treatment plan that incorporates universal screening with monitoring for all patients with cancer who are considered for opioid treatment to assess their risk for opioid misuse and harm. Timely identification with appropriate management, including referral of at-risk patients, will allow oncology professionals to optimize the risk-to-benefit and support the safe use of opioids for patients with cancer.

Safe Opioid Use: Management of Opioid-Related Adverse Effects and Aberrant Behaviors

Opioids are highly effective for cancer pain but are associated with multiple adverse effects and risk of addiction. This article provides a synopsis on the management of various opioid-related adverse effects and strategies to minimize aberrant opioid use in patients who have cancer. Many adverse effects can be effectively managed. Some patients on chronic opioid therapy may demonstrate aberrant behaviors suggestive of opioid misuse or diversion. Through intensive education, longitudinal monitoring, early identification, and timely management, clinicians can optimize the risk to benefit ratio to support safe opioid use.

Opioid-induced Hallucinations: A Review of the Literature, Pathophysiology, Diagnosis, and Treatment

Despite their association with multiple adverse effects, opioid prescription continues to increase. Opioid-induced hallucination is an uncommon yet significant adverse effect of opioid treatment. The practitioner may encounter patient reluctance to volunteer the occurrence of this phenomenon because of fears of being judged mentally unsound. The majority of the literature concerning opioid-induced hallucinations arises from treatment during end-of-life care and cancer pain. Because the rate of opioid prescriptions continues to increase in the population, the rate of opioid-associated hallucinations may also conceivably increase. With a forecasted increase in the patient-to-physician ratio, opioid therapy is predicted to be provided by practitioners of varying backgrounds and medical specialties. Hence, knowledge of the pharmacology and potential adverse effects of these agents is required. This review seeks to increase awareness of this potential complication through a discussion of the literature, potential mechanisms of action, diagnosis, and treatment strategies.

Resilience and Vulnerability to Pain and Inflammation in the Hippocampus

Increasing evidence demonstrates the importance of hippocampal neurogenesis, a fundamental mechanism of neuroplasticity associated with cognition and emotion, in correlation to neurodegenerative and psychiatric disorders. Neuropsychiatric disorders are often a result of chronic stress or pain followed by inflammation; all these conditions manifest cognitive deficits and impairments in neurogenesis. However, while some individuals are more susceptible to stress, others are able to adapt to new environments via mechanisms of resilience. In light of this emerging field and based on extensive research, the role of neurogenesis is summarized and presented as a potentially powerful therapeutic tool.

Cognitive Effects and Sedation

OBJECTIVE

Cognitive effects and sedation (CES) are prevalent in chronic nonmalignant pain populations receiving long-term opioid therapy and are among the most common reasons patients discontinue opioid use. In this narrative review, we describe the phenomenology, epidemiology, mechanisms, assessment, and management of opioid-related CES.

DESIGN

We reviewed the empirical and theoretical literature on CES in opioid-treated populations with chronic pain. Data on long-term opioid therapy (≥ 3 months in duration) in chronic nonmalignant pain patients were sought.

RESULTS

The phenomenology of CES includes: inattention, concentration difficulties, memory deficits, psychomotor dysfunction, perceptual distortions, and executive dysfunction and somnolence, sleep disorders, and lethargy. Deficits may be caused by unrelieved pain or opioid therapy alone, or from a combination of these and other factors. Mechanisms include central nervous system effects, for example, direct toxic effects on neurons resulting in decreased consciousness; direct effects on processing and reaction resulting in cognitive or psychomotor impairment, and inhibitory effects on cholinergic activity. Pharmacological management approaches may include opioid dose reduction and rotation or psychostimulant use. Nonpharmacological approaches may include cognitive-behavioral therapy, mindfulness-based stress reduction, acupuncture, exercise, and yoga.

CONCLUSIONS

The most prevalent CES include: memory deficits (73-81%), sleep disturbance (35-57%), and fatigue (10%). At its most severe, extreme cognitive dysfunction can result in frank delirium and decreased alertness can result in coma. Emotional distress, sleep disorders, and other comorbidities and treatments can worsen CES, particularly among the elderly. Conclusions about the neuropsychological domains affected by opioids are limited due to the heterogeneity of studies and methodological issues.

Genetic variation and cognitive dysfunction in opioid-treated patients with cancer

BACKGROUND AND PURPOSE

The effects of single-nucleotide polymorphisms (SNPs) on the cognitive function of opioid-treated patients with cancer until now have not been explored, but they could potentially be related to poor functioning. This study aimed at identifying associations between SNPs of candidate genes, high opioid dose, and cognitive dysfunction.

METHODS

Cross-sectional multicenter study (European Pharmacogenetic Opioid Study, 2005-2008); 1586 patients; 113 SNPs from 41 genes.

INCLUSION CRITERIA

cancer, age ≥18 year, opioid treatment, and available genetic data. Cognitive assessment by Mini-Mental State Examination (MMSE).

ANALYSES

SNPs were rejected if violation of Hardy-Weinberg equilibrium (P < 0.0005), or minor allele frequency <5%; patients were randomly divided into discovery sample (2/3 for screening) and validation sample (1/3 for confirmatory test); false discovery rate of 10% for determining associations (Benjamini-Hochberg method). Co-dominant, dominant, and recessive models were analyzed by Kruskal-Wallis and Mann-Whitney tests.

RESULTS

In the co-dominant model significant associations (P < 0.05) between MMSE scores and SNPs in the HTR3E,TACR1, and IL6 were observed in the discovery sample, but the replication in the validation sample did not confirm it. Associations between MMSE scores among patients receiving ≥400 mg morphine equivalent dose/day and SNPs in TNFRSF1B,TLR5,HTR2A, and ADRA2A were observed, but they could not be confirmed in the validation sample. After correction for multiple testing, no SNPs were significant in the discovery sample. Dominant and recessive models also did not confirm significant associations.

CONCLUSIONS

The findings did not support influence of those SNPs analyzed to explain cognitive dysfunction in opioid-treated patients with cancer.

Assessing cognitive function in adults during or following chemotherapy: a scoping review

PURPOSE

The purpose of this scoping review was to determine the feasibility of conducting a systematic review of approaches for screening or assessing cognitive function that were comprehensive and that could be incorporated into clinical settings.

METHODS

Using the scoping review approach developed by Arksey and O'Malley, we searched Ovid Embase 1980-, Ovid PsycINFO 1806-, Ovid Health and Psychosocial Instruments 1985-, EBSCOhost CINAHL, ISI Web of Science (Science Citation Index 1900-), Social Sciences Citation Index 1900-, Conference Proceedings Citation Index -Science 1990-, Conference Proceedings Citation Index -Social Science & Humanities 1990-, Scopus 1960-, with no language restrictions. Searches were conducted in April 2009 and updated in February 2013. Studies of adults treated with chemotherapy that included at least seven of the eight domains of cognition were included.

RESULTS

Eleven studies met inclusion criteria. No screening tools suitable for inclusion in a clinic were identified. The studies reviewed varied by inclusion/exclusion criteria, design, and instruments for assessing cognitive function, and thus, there are not yet enough studies to warrant a systematic review on this topic.

The hippocampus and TNF: Common links between chronic pain and depression

Major depression and chronic pain are significant health problems that seriously impact the quality of life of affected individuals. These diseases that individually are difficult to treat often co-exist, thereby compounding the patient's disability and impairment as well as the challenge of successful treatment. The development of efficacious treatments for these comorbid disorders requires a more comprehensive understanding of their linked associations through common neuromodulators, such as tumor necrosis factor-α (TNFα), and various neurotransmitters, as well as common neuroanatomical pathways and structures, including the hippocampal brain region. This review discusses the interaction between depression and chronic pain, emphasizing the fundamental role of the hippocampus in the development and maintenance of both disorders. The focus of this review addresses the hypothesis that hippocampal expressed TNFα serves as a therapeutic target for management of chronic pain and major depressive disorder (MDD).

Delirium diagnostic and classification challenges in palliative care: subsyndromal delirium, comorbid delirium-dementia, and psychomotor subtypes

CONTEXT

Delirium often presents difficult diagnostic and classification challenges in palliative care settings.

OBJECTIVES

To review three major areas that create diagnostic and classification challenges in relation to delirium in palliative care: subsyndromal delirium (SSD), delirium in the context of comorbid dementia, and classification of psychomotor subtypes, and to identify knowledge gaps and research priorities in relation to these three areas of focus.

METHODS

We combined multidisciplinary input from delirium researchers and knowledge users at an international delirium study planning meeting and relevant PubMed literature searches as the knowledge synthesis strategy in this review.

RESULTS

We identified six (SSD), 33 (dementia), and 44 (psychomotor subtypes) articles of relevance in relation to the focus of our review. Recent literature data highlight the frequency and impact of SSD, the relevance of comorbid dementia, and the propensity for a hypoactive presentation of delirium in the palliative population. The differential diagnoses to consider are wide and include pain, fatigue, mood disturbance, psychoactive medication effects, and other causes for altered consciousness.

CONCLUSION

Challenges in the diagnosis and classification of delirium in people with advanced disease are compounded by the generalized disturbance of central nervous system function that occurs in the seriously ill, often with comorbid illness, including dementia. Further research is needed to delineate the pathophysiological and clinical associations of these presentations and thus inform therapeutic strategies. The expanding aged population and growing focus on dementia care in palliative care highlight the need to conduct this research.

Delirium superimposed on Charles Bonnet syndrome: a case study

Older adults with visual impairment may experience visual hallucinations in the setting of normal cognition and absence of psychiatric illness. This phenomenon is referred to as Charles Bonnet syndrome. Information concerning Charles Bonnet syndrome predominantly comes from case studies. Reassuring the person experiencing the hallucinations they are not suffering from psychosis constitutes the mainstay of treatment. What follows is the case of a vision impaired, older adult male with known Charles Bonnet syndrome, who, following emergency surgery and associated delirium while in the intensive care unit, experiences an aggressive change in hallucinations. Nurses need to understand the pathology and characteristics of Charles Bonnet syndrome in order to distinguish it from other pathologies underlying hallucinations. This knowledge is necessary to provide safe, patient-centered care for older adults.

Options for treating postherpetic neuralgia in the medically complicated patient

Patients with postherpetic neuralgia (PHN) are often of advanced age or immunocompromised and likely to have ≥1 comorbid medical condition for which they receive ≥1 medication (polypharmacy). Comorbidities affecting renal or hepatic function can alter pharmacokinetics, thereby impacting the efficacy or tolerability of PHN analgesic therapies. Cardiovascular, cerebrovascular, or psychiatric comorbidities may increase patient vulnerability to potential adverse events associated with some PHN analgesic therapies. Because PHN is a localized condition, localized therapy with a topical analgesic (lidocaine patch 5% and capsaicin 8% patch or cream) may provide adequate efficacy while mitigating the risk of systemic adverse events compared with oral analgesics (eg, tricyclic antidepressants, anticonvulsants, opioids). However, combined therapy with a topical and an oral analgesic or with >1 oral analgesic may be needed for optimal pain management in some patients. This review summarizes how comorbidities and concomitant medications should be taken into account when selecting among available pharmacotherapies for PHN and provides recommendations for the selection of therapies that will provide analgesia while minimizing the risk of adverse events.

The use of very-low-dose methadone for palliative pain control and the prevention of opioid hyperalgesia

BACKGROUND

Opioid dose escalation may cause hyperalgesia, mediated by the N-methyl-D-aspartate (NMDA) pathway. Methadone is an atypical opioid that inhibits hyperalgesia through NMDA-blockade, especially at low doses.

OBJECTIVE

To evaluate the efficacy of using very-low-dose methadone as the sole long-acting opioid agent in a hospice practice.

DESIGN

A retrospective, observational study of the use of methadone, ≤15 mg daily, with as-needed short-acting opiates. Adjuvant nonopioid medications included haloperidol, which may have NMDA-blocking effects.

SETTING/SUBJECTS

We reviewed the records of 240 patients admitted to a community-based hospice from July 1, 2011 to April 1, 2012, with data collected until hospice discharge or until April 30, 2012.

MEASUREMENTS

Descriptive statistics were used to summarize patient demographics, medication regimens, and reported pain scores measured on a numeric rating scale from 0 to 10.

RESULTS

All patients received short-acting opiates, in a morphine-equivalent dose of 5 mg every 4 hours as needed, while 40% also received methadone at a median daily dose of 5 mg. Of those on methadone, almost half received scheduled haloperidol. The population had a median reported pain score of 0 and a peak score of 3, with similar results seen for cancer and noncancer groups. Two-thirds of patients never reported a pain score greater than 3.

CONCLUSION

The use of very-low-dose methadone in conjunction with adjuvant haloperidol resulted in excellent pain control without dose escalation or opioid-induced hyperalgesia, for both cancer and noncancer diseases. We conclude that low-dose methadone should be part of first-line treatment in palliative pain management.

Parenteral hydration in patients with advanced cancer: a multicenter, double-blind, placebo-controlled randomized trial

PURPOSE

The vast majority of patients with cancer at the end of life receive parenteral hydration in hospitals and no hydration in hospice, with limited evidence supporting either practice. In this randomized controlled trial, we determined the effect of hydration on symptoms associated with dehydration, quality of life, and survival in patients with advanced cancer.

PATIENTS AND METHODS

We randomly assigned 129 patients with cancer from six hospices to receive parenteral hydration (normal saline 1 L per day) or placebo (normal saline 100 mL per day) daily over 4 hours. The primary outcome was change in the sum of four dehydration symptoms (fatigue, myoclonus, sedation and hallucinations, 0 = best and 40 = worst possible) between day 4 and baseline. Secondary outcomes included Edmonton Symptom Assessment Scale (ESAS), Memorial Delirium Assessment Scale (MDAS), Nursing Delirium Screening Scale (NuDESC), Unified Myoclonus Rating Scale (UMRS), Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F), Dehydration Assessment Scale, creatinine, urea, and overall survival. Intention-to-treat analysis was conducted to examine the change by day 4 ± 2 and day 7 ± 2 between groups.

RESULTS

The hydration (n = 63) and placebo (n = 66) groups had similar baseline characteristics. We found no significant differences between the two groups for change in the sum of four dehydration symptoms (-3.3 v -2.8, P = .77), ESAS (all nonsignificant), MDAS (1 v 3.5, P = .084), NuDESC (0 v 0, P = .13), and UMRS (0 v 0, P = .54) by day 4. Results for day 7, including FACIT-F, were similar. Overall survival did not differ between the two groups (median, 21 v 15 days, P = .83).

CONCLUSION

Hydration at 1 L per day did not improve symptoms, quality of life, or survival compared with placebo.

Opioid side effects and their treatment in patients with chronic cancer and noncancer pain

Opioids are the foundation of standard analgesic regimens for moderate to severe pain due to life-threatening illnesses such as cancer, and are increasingly employed in chronic noncancer pain of the same severity. Opioids are frequently used for long periods in these populations, sometimes for years. However, side effects are common and may reduce quality of life, or become life threatening, and frequently cause patients to discontinue opioid therapy. Successful opioid therapy dictates that benefits of analgesia outweigh safety concerns. The mechanisms, incidence, and treatment or prevention of commonly reported side effects in chronic pain populations are reviewed, employing best available evidence along with empiric practice. General management strategies include switching opioids ("opioid rotation"), discontinuation of concurrent medications that exacerbate side effects, and symptomatic treatment. In addition, recently recognized adverse events that occur after long-term opioid therapy are discussed. High-quality evidence is lacking for the treatment of most side effects, and the true incidence, underlying mechanisms, and clinical implications of long-term responses to opioid therapy are not yet fully understood.

Adverse effects in hospice patients with chronic kidney disease receiving hydromorphone

BACKGROUND

Pain is one the most common symptoms experienced by palliative care patients. The treatment of pain involves the use of strong opioids such as hydromorphone, morphine, methadone, fentanyl, oxycodone, oxymorphone, or levorphanol for moderate to severe pain. Hydromorphone is metabolized by the liver to hydromorphone-3-glucuronide (H3G), a compound that can potentially cause neuroexcitatory phenomena with accumulation. Pharmacokinetic studies have shown that H3G levels in patients with renal insufficiency are 4 times as high as those with normal renal function; however, reports have been conflicting as to whether or not it is safe to use hydromorphone in renal insufficiency.

METHODS

In this study we sought to determine the prevalence of neuroexcitation in patients with renal insufficiency who were given hydromorphone, as measured by the glomerular filtration rate (GFR), and to investigate factors associated with increased risk of neuroexcitation in this patient group. For the 12- month period from June 2007 through June 2008, charts of inpatient hospice patients that showed a glomerular filtration rate of <60 (mL/min/1.73 m(2)) and hydromorphone administration for pain control via continuous infusion were reviewed for the occurrence of neuroexcitatory effects, including tremor, myoclonus, agitation, cognitive dysfunction, and seizures.

RESULTS

Overall prevalence of neuroexcitatory effects were: tremor 11 (20%), myoclonus 11 (20%), agitation 26 (48%), and cognitive dysfunction 21 (39%). No seizures were observed. No neuroexcitatory effects were observed for the lowest quartile of dose or duration of hydromorphone. There was a strong and graded increase in neuroexcitatory effects with increasing quartile of dose or duration of hydromorphone for agitation (dose, p<0.0001; duration, p<0.0001) and cognitive dysfunction (dose, p<0.0002; duration, p<0.002). Consistent but weaker trends were observed for tremor and myoclonus.

CONCLUSION

Parenteral hydromorphone has few neuroexcitatory symptoms until H3G accumulates past a neurotoxic threshold, such as might occur with increasing dose or duration, which, when exceeded, causes neuroexcitatory symptoms to manifest.

European Palliative Care Research collaborative pain guidelines. Central side-effects management: what is the evidence to support best practice in the management of sedation, cognitive impairment and myoclonus?

This is a systematic review examining the management of opioid-induced central side effects. It has been conducted as part of a larger European Palliative Care Research collaborative review into the use and role of opioids in cancer pain. The review process identified 26 studies that met the inclusion criteria. The overall quality of the data was low and the few recommendations that can be made are weak and require confirmatory studies. The main central side effects examined were sedation, cognitive failure, sleep disturbance and myoclonus. Overall there is limited evidence for the use of methylphenidate in counteracting opioid-induced sedation and cognitive disturbance. No clear recommendations can be made concerning other individual drugs for the management of any of the central side effects examined. Given the lack of available data from this review there need to be further prospective controlled trials to confirm or refute these findings.

'Like a sieve': an exploratory study on cognitive impairments in patients with multiple myeloma

The aim of this study was to obtain a more in-depth understanding of cognitive impairments and concerns as described by patients with multiple myeloma and the strategies used to cope with them. Semi-structured qualitative interviews were undertaken with 15 multiple myeloma patients of differing age ranges and at various stages of their disease. Various cognitive impairments, such as problems with short-term memory, poor recall and lack of concentration were observed and/or expressed in at least 10 out of 15 patients, all of them long(er)-term survivors. In some patients cognitive impairments significantly interfered with their personal and professional lives, and for some patients these were described as permanent. The patients used various coping strategies, from denial, taking notes, writing diaries, reading simpler texts, using talking books and videos, to using systems for counting medication to cope with the results of their cognitive impairment. Our findings differ from much of the contemporary literature which states that if cognitive impairments in cancer patients occur, they are mostly mild and transient. More proactive supportive care is needed to help patients with multiple myeloma to cope with poorer cognitive functioning.

Delirium in Palliative Care Patients: Focus on Pharmacotherapy

Patients receiving palliative care often possess multiple risk factors and predisposing conditions for delirium. The impact of delirium on patient care in this population may also be far-reaching: affecting not only quality of remaining life but the dying process experienced by patients, caregivers, and the medical team as well. As palliative care focuses on comfort and symptom management, the approach to assessment and subsequent treatment of delirium in palliative care patients may prove difficult for providers to navigate. This article summarizes the multifactorial nature, numerous predisposing medical risk factors, neuropsychiatric adverse effects of palliative medications, pharmacokinetic changes, and challenges complicating delirium assessment and provides a systematic framework for assessment. The benefits, risks, and patient-specific considerations for treatment selection are also discussed.

Opioid therapy for osteoarthritis and chronic low back pain

BACKGROUND

Chronic low back pain (CLBP) and osteoarthritis (OA) of any joint are highly prevalent, occurring in > 50% of US adults aged ≥ 60 years. Opioids are prescribed more frequently for CLBP and OA than for any other noncancer pain, and the judicious use of opioids is recommended by treatment guidelines for the management of CLBP and OA pain.

OBJECTIVE

To review the appropriate role of opioid analgesics in the treatment of patients with moderate-to-severe pain due to CLBP or OA and provide recommendations for best practices when prescribing opioids.

METHODS

Articles were identified through a search of PubMed. Additional references were identified for inclusion from the reference lists of articles identified via the literature search, treatment guidelines, and Cochrane Reviews.

RESULTS

The available data suggest that opioid therapy represents a valuable treatment option in patients who do not respond to other analgesics and in whom the potential benefits of treatment outweigh the potential risks. Prescribing physicians need to perform vigilant patient screening and monitoring for signs of abuse, intervene promptly to manage or prevent adverse events and drug interactions, tailor opioid therapy to individual patients' comorbidities, and know how to switch or rotate opioids to find the best treatment option.

CONCLUSIONS

Prescribers need to understand the place of opioid therapy in a multimodal treatment program that includes patient rehabilitation to reduce pain and improve function. The analgesic benefits of opioids must be balanced against concerns about addiction and abuse, adverse events, and their potential impact on other aspects of treatment.

Implications of opioid analgesia for medically complicated patients

Opioid analgesics have an established role in the management of postoperative pain and cancer pain, and are gaining acceptance for the management of moderate to severe chronic noncancer pain, most notably chronic low back pain and osteoarthritis, that does not respond to other interventions. Many patients with chronic pain have co-morbid medical conditions that may complicate opioid therapy. Selecting the appropriate opioid requires knowledge of how individual opioids differ with respect to metabolism and interaction with concurrent medications, as well as the reasons why specific medical conditions may influence their efficacy and tolerability. Polypharmacy is a common complicating condition in the elderly and in patients with psychiatric illness, cancer, cardiovascular disease, diabetes mellitus or other chronic illnesses. Polypharmacy, though often necessary for patients with multiple medical conditions, also multiplies the risk of drug interactions. Pharmacokinetic drug interactions can increase or reduce exposure to the opioid or concurrent medications, reducing efficacy and/or tolerability and increasing toxicity. Pharmacodynamic interactions can enhance the depressive effects of opioids, compromising safety. Patients with impaired renal or hepatic function may have difficulty clearing or metabolizing opioids and concurrent medications, leading to increased risk of adverse events. Patients with cardiovascular, cerebrovascular or respiratory disease (including smokers of >/=2 packs/day with no other diagnosis) may be more susceptible to respiratory depression, bradycardia and hypotension with any opioid, and a few specific opioids pose additional risks. Patients with cerebrovascular disease, dementia, brain injury or psychiatric illness are more susceptible to opioid effects on the CNS, which can include euphoria, cognitive impairment and sedation. Appropriate opioid selection may mitigate these effects. Even in older patients, addiction, abuse and misdirection of prescribed opioids are of concern. Higher risk exists for patients with psychiatric illness, history of substance abuse, and identifiable substance abuse risk factors. Screening for abuse potential and vigilant patient monitoring should be routine. Opioids differ in their ability to produce euphoria, based on opioid receptor agonism, but substance abusers may be more influenced by availability, familiarity and cost factors. Consequently, opioid selection has limited influence on abuse potential but can facilitate ease of monitoring. This review provides an overview of opioid use in medically complicated patients and recommendations on how to optimize analgesia while avoiding adverse events and drug interactions in the clinical setting. Articles cited in this review were identified via a search of EMBASE and PubMed. Articles selected for inclusion discussed characteristics of specific opioids and general physiological aspects of opioid therapy in important patient populations.

Radiation, chemotherapy, and symptom management in cancer-related cognitive dysfunction

Patients with cancer are concerned about their ability to interact with friends and family and to perform activities associated with daily living. The combined effects of the disease process, its treatment with surgery, radiation, and chemotherapy, and the medications used to manage symptoms may all impact cognitive function. Minimizing the effect of each treatment modality on cognitive processing requires an understanding of how these treatment modalities may impact cognition.

Comparative cognitive and subjective side effects of immediate-release oxycodone in healthy middle-aged and older adults

This study measured the objective and subjective neurocognitive effects of a single 10-mg dose of immediate-release oxycodone in healthy, older (> 65 years), and middle-aged (35 to 55 years) adults who were not suffering from chronic or significant daily pain. Seventy-one participants completed 2 separate study days and were blind to medication condition (placebo, 10-mg oxycodone). Plasma oxycodone concentration peaked between 60 and 90 minutes postdose (P < .01) and pupil size, an indication of physiological effects of the medication, peaked at approximately 90 to 120 minutes postdose (P < .01). Significant declines in simple and sustained attention, working memory, and verbal memory were observed at 1 hour postdose compared to baseline for both age groups with a trend toward return to baseline by 5 hours postdose. For almost all cognitive measures, there were no medication by age-interaction effects, which indicates that the 2 age groups exhibited similar responses to the medication challenge. This study suggests that for healthy older adults who are not suffering from chronic pain, neurocognitive and pharmacodynamic changes in response to a 10-mg dose of immediate-release oxycodone are similar to those observed for middle-aged adults.

PERSPECTIVE

Study findings indicate that the metabolism, neurocognitive effects, and physical side effects of oral oxycodone are similar for healthy middle-aged and older adults. Therefore, clinicians should not avoid prescribing oral opioids to older adults based on the belief that older adults are at higher risk for side effects than younger adults.

Delirium issues in palliative care settings

OBJECTIVE

The objective of this study is to provide an expert review of delirium in the context of palliative care.

METHODS

Based on a primary selection criterion, firstly, studies were included for review if the population studied either had a diagnosis of advanced cancer or was receiving palliative care; alternatively, in the absence of data derived from these populations, studies conducted in other populations were included. Secondly, from the studies meeting the primary selection criterion, we selected those that examined specific standard outcome measures. Thirdly, we selected studies and literature reviews that identified delirium research issues.

RESULTS

Delirium occurs commonly in the context of palliative care where it is likely to cause heightened distress for patients, carers, and families alike, and make interpretation of pain and other symptoms extremely difficult. There is a profound dearth of rigorous studies on delirium in this setting. Ambiguous terminology, varying definitions in internationally recognized classification systems, and failure to use validated assessment tools lead to wide-ranging incidence and prevalence of delirium episodes in such populations. Episodes are usually multifactorial in origin and may portend poor prognosis by preceding death in many cases. Despite this, many are often at least partially reversible with relatively low-burden interventions. The patient's disease status, previous quality of life, and prior expressed wishes regarding goals of care should all be taken into account. Antipsychotics are the pharmacotherapeutic agents most commonly used to control symptoms despite limited evidence either supporting their efficacy or examining their adverse event profile. Often, symptomatic control alone is indicated. In cases with refractory symptoms, deeper or "palliative" sedation may be required.

CONCLUSION

Further research is needed regarding delirium recognition, phenomenology, the development of low-burden instruments for assessment, family education, predictive models for reversibility, and evidence-based guidelines on the appropriate use of palliative sedation.

Delirium in cancer patients: a focus on treatment-induced psychopathology

PURPOSE OF REVIEW

Delirium is a neuropsychiatric syndrome that occurs frequently in cancer patients, especially in those with advanced disease. Recognition and effective management of delirium is particularly important in supportive and palliative care, especially in view of the projected increase in the elderly population and the consequent potential for the number of patients both diagnosed and living longer with cancer to increase substantively.

RECENT FINDINGS

Studies of delirium in a variety of settings have generated new insights into phenomenology, assessment tools, the psychomotor subtypes, potential patho-physiological markers, pathogenesis, reversibility, and the role of sedation in symptom control.

SUMMARY

Validated tools exist to assist in the assessment of delirium. Although our understanding of the pathogenesis of delirium has improved somewhat, there remains a compelling need to further elucidate the underlying pathophysiology, especially in relation to opioids and the other psychoactive medications that are used in supportive care. Further trials are needed, especially in patients with advanced disease to determine predictive models of reversibility, preventive strategies, outcomes, and to assess the role of antipsychotic and other medications in symptomatic management.