Clinical pharmacology of analgesics in old age and frailty

Chronic Pain, Opioid Use Disorder, and Clinical Management Among Older Adults

Because of unique factors related to physiological changes and altered metabolism in advanced age, special attention is needed concerning chronic pain, opioid use, and opioid use disorder among older adults. Clinicians need to follow the most updated clinical guidelines regarding opioid prescribing. Routine screening and awareness are the keys to identifying opioid use disorder. Comprehensive assessments often require both pain assessment (including functional status) and substance use assessment, including the use of urine toxicological testing and structured, validated screening tools and instruments. Comprehensive, interdisciplinary efforts are critical in managing the care of older adults with chronic pain and opioid use disorder. A collaborative approach that includes substance abuse treatment and pain management (including pain subspecialty care) is often recommended. Medications for opioid use disorder have been extensively studied and have the most convincing evidence to date, and psychosocial treatments may be beneficial in some circumstances.

Rethinking toxicity testing: Influence of aging on the outcome of long-term toxicity testing and possible remediation

Traditionally, toxicity testing is conducted at fixed dose rates (i.e., mg/kg/day) without considering life-changing events, e.g., stress, sickness, aging- and/or pregnancy-related changes in physical, physiological and biochemical parameters. In humans, life-changing events may cause systemic dose non-proportionality requiring modulation of drug dosage; similar changes occur in animals altering systemic dose during chronic/carcinogenic testing leading to "late-occurring" effects in some studies. For example, propylene monomethyl ether, an industrial chemical, initially induced sedation in rats and mice with recovery upon induction of hepatic CYPs after ~1 week. Sedation reappeared in rats but not in mice after ~12 months of exposure due to decreased CYP activity in rats, elderly mice were able to maintain slightly higher CYP activity avoiding recurrence of sedation. The systemic dose of two pharmaceuticals (doxazosin and brimonidine tartrate) increased up to 6-fold in ≥12-month old rats with no toxicity. In a rat reproductive toxicity study, systemic dose of 2,4-D, an herbicide, rapidly increased due to increased consumption of 2,4-D-fortified diet during pregnancy, lactation and neonatal growth, requiring adjustment to maintain the targeted systemic dose. Ideally, toxicological studies should be based on systemic dose with the option of modulating external dose rates to maintain the targeted systemic dose. Systemic dose can easily be monitored in selected core study animals at desired intervals considering recent developments in sampling and analysis at a fraction of the overall cost of a study.

A Pain eHealth Platform for Engaging Obese, Older Adults with Chronic Low Back Pain in Nonpharmacological Pain Treatments: Protocol for a Pilot Feasibility Study

Background

Low back pain is a costly healthcare problem and the leading cause of disability among adults in the United States. Primary care providers urgently need effective ways to deliver evidence-based, nonpharmacological therapies for chronic low back pain. Guidelines published by several government and national organizations have recommended nonpharmacological and nonopioid pharmacological therapies for low back pain.

Objective

The Pain eHealth Platform (PEP) pilot trial aims to test the feasibility of a highly innovative intervention that (1) uses an electronic health record (EHR) query to systematically identify a phenotype of obese, older adults with chronic low back pain who may benefit from Web-based behavioral treatments; (2) delivers highly tailored messages to eligible older adults with chronic low back pain via the patient portal; (3) links affected patients to a Web app that provides education on the efficacy of evidence-based, nonpharmacological, behavioral pain treatments; and (4) directs patients to existing Web-based health treatment tools.

Methods

Using a three-step modified Delphi method, an expert panel of primary care providers will define a low back pain phenotype for an EHR query. Using the defined low back pain phenotype, an EHR query will be created to identify patients who may benefit from the PEP. Up to 15 patients with low back pain will be interviewed to refine the tailored messaging, esthetics, and content of the patient-facing Web app within the PEP. Up to 10 primary care providers will be interviewed to better understand the facilitators and barriers to implementing the PEP, given their clinic workflow. We will assess the feasibility of the PEP in a single-arm pragmatic pilot study in which secure patient portal invitations containing a hyperlink to the PEP Web app are sent to 1000 patients. The primary outcome of the study is usability as measured by the System Usability Scale.

Results

Qualitative interviews with primary care providers were completed in April 2019. Qualitative interviews with patients will begin in December 2019.

Conclusions

The PEP will leverage informatics and the patient portal to deliver evidence-based nonpharmacological treatment information to adults with chronic low back pain. Results from this study may help inform the development of Web-based health platforms for other pain and chronic health conditions.

International Registered Report Identifier (IRRID)

DERR1-10.2196/14525

Adverse drug reactions due to opioid analgesic use in New South Wales, Australia: a spatial-temporal analysis

Background

Pharmaceutical opioid analgesic use continues to rise and is associated with potentially preventable harm including hospitalisation for adverse drug reactions (ADRs). Spatial detection of opioid-related ADRs can inform future intervention strategies. We aimed to investigate the geographical disparity in hospitalised ADRs related to opioid analgesic use, and to evaluate the difference in patient characteristics between areas inside and outside the geographic clusters.

Methods

We used the all-inclusive Admitted Patient Dataset for an Australian state (New South Wales, NSW) to identify patients admitted for opioid-related ADRs over a 10-year period (July 2004 to June 2014). A space-time analysis was conducted using Kulldroff’s scan statistics to identify statistically significant spatial clusters over time. Relative risk (RR) was computed with p-value based on Monte Carlo Simulation. Chi-square test was used to compare proportional difference in patient clustering.

Results

During the study period, we identified four statistically significant geographic clusters (RRs: 1.63–2.17) during 2004–08; and seven clusters (RRs: 1.23–1.69) during the period 2009–14. While identified high-risk clusters primarily covered areas with easier access to health services, those associated with socioeconomically disadvantaged areas and individuals with mental health disorders experienced more unmet healthcare needs for opioid analgesic safety than those from the rest of the State. Older people (≥65 years and over) accounted for 62.7% of the total study population and were more susceptible to opioid-related ADRs than younger people,. In the first five-year period the clusters included a greater proportion of people with cancer in contrast to the second five-year period in which there was a lesser proportion of people with cancer.

Conclusions

These results suggest that there is significant spatial-temporal variation in opioid-related ADRs and future interventions should target vulnerable populations and high-risk geographical areas to improve safer use of pharmaceutical opioid analgesics.

Substance Addiction in Old Age

Abstract. There is a lack of studies using a structured face-to-face interview focusing on the full spectrum of substance addictions according to ICD or DSM classification systems in older patients. We therefore examined a cohort of 400 randomly selected, at least 65-year-old inpatients of a general hospital concerning addictive disorders using a well-tested structured clinical interview (DSM-IV-TR-based SKID-I). Nearly one third of this cohort was substance dependent: The 12-month prevalence rate for nicotine was 10.3% and for alcohol dependence 3%, with 24.4% and 66.7%, respectively, being severely dependent. These rates were similar to those found in the general German population of persons under 65 year of age. A fifth of the cohort was (mostly mildly) dependent on prescription drugs, remarkably including nonopioid analgesics. One case with a previous dependence on gabapentin was identified. Identification and management of addiction disorders should be considered as part of the basic geriatric assessment.

Drug-induced liver injury in older adults

Drug-induced liver injury (DILI) is an important cause of hospitalisation and of medication deregistration. In old age, susceptibility to DILI is affected by changes in physiology and increased interindividual variability, compounded by an increased prevalence of disease and the frailty syndrome. While dose-related or predictable DILI reactions are often detected in preclinical trials, the occurrence of rare hypersensitivity or idiosyncratic reactions cannot be reliably predicted from preclinical studies or even by clinical trials. The limited participation of older adults in clinical trials means that the susceptibility of this population to DILI is largely unknown. Vigilance during clinical trials and postmarketing surveillance must be universally practised. A systematic approach should be taken to determine not only which medicines are hepatotoxic and should be removed from the market, but also the hepatotoxicity risks from marketed drugs to consumers with different characteristics, many of whom are older people.

Chronic Pain in Older Adults

This review summarizes existing evidence relevant to the epidemiology of chronic pain in older adults, age-related differences relevant to pain, pain assessment, and important considerations regarding pain management in later life. Features unique to pain assessment in older adults include the likelihood of multiple diagnoses contributing to chronic pain, the ability of older adults to self-report, including those with mild to moderate cognitive impairment, and recognition that some older adults with cognitive impairment may demonstrate various behaviors to communicate pain. Management is best accomplished through a multimodal approach, including pharmacologic and nonpharmacologic treatments, physical rehabilitation, and psychological therapies. Interventional pain therapies may be appropriate in select older adults, which may reduce the need for pharmacologic treatments.

What analgesics do older people use prior to initiating oxycodone for non-cancer pain? A retrospective database study

BACKGROUND

Increased oxycodone use has been associated with adverse drug events, non-medical use and overdose deaths.

OBJECTIVES

To explore patterns of non-opioid, weak opioid and strong opioid use prior to initiation of oxycodone for non-cancer pain in a predominantly older Australian population.

METHODS

A retrospective study was conducted using the Australian Government Department of Veterans' Affairs administrative claims database. Analgesic use 12 months prior to incident dispensing of oxycodone was determined for people in the community and in residential aged-care facilities (RACFs). Log-binomial regression was used to compute adjusted rate ratios (RRs) and 95 % confidence intervals (95 % CIs) for the use of other analgesics prior to initiating oxycodone.

RESULTS

Of 10,791 people who initiated oxycodone in 2010, 26 % in community settings and 13 % in RACFs were not dispensed other analgesics in the 12 months prior to initiating oxycodone. Thirty-four percent and 20 % of those in community settings and RACFs, respectively, were not dispensed other analgesics in the previous 4 months. Co-morbidity had little impact on prior analgesic use. Each additional co-morbid condition was associated with a 1.4 % increased likelihood (RR 1.014, 95 % CI 1.012-1.016; p < 0.0001) and a 1.2 % increased likelihood (RR 1.012, 95 % CI 1.009-1.015; p < 0.0001) of being dispensed another analgesic prior to initiating oxycodone in community and RACF settings, respectively.

CONCLUSIONS

Oxycodone is frequently initiated for non-cancer pain without first trialing other analgesics. This highlights the need for prescribing practices to be reviewed in light of increasing concerns about adverse drugs events and death due to oxycodone, particularly in older people.

Analgesic use, pain and daytime sedation in people with and without dementia in aged care facilities: a cross-sectional, multisite, epidemiological study protocol

INTRODUCTION

People living with dementia may experience and express pain in different ways to people without dementia. People with dementia are typically prescribed fewer analgesics than people without dementia indicating a potential difference in how pain is identified and treated in these populations. The objectives of this study are to (1) investigate the prevalence of analgesic load, pain and daytime sedation in people with and without dementia in Australian residential aged care facilities (RACFs), and (2) investigate the clinical and diagnostic associations between analgesic load, pain and daytime sedation in people with and without dementia in Australian RACFs.

METHODS/ANALYSIS

This will be a cross-sectional study of 300 permanent residents of up to 10 low-level and high-level RACFs in South Australia with and without dementia. Trained study nurses will administer validated and dementia-specific assessments of self-reported and clinician-observed pain, sedation and other clinical and humanistic outcomes. Medicine-use data will be extracted directly from each resident's medication administration chart. Binary and multinominal logistic regression will be used to compute unadjusted and adjusted ORs and 95% CIs for factors associated with pain, analgesic load and daytime sedation. These factors will include dementia severity, behavioural and psychological symptoms, quality of life, resident satisfaction, attitudes towards medicines, activities of daily living and nutritional status.

ETHICS AND DISSEMINATION

Institutional ethics approval has been granted. The findings will be disseminated through public lectures, professional and scientific conferences and in peer-reviewed journal articles. The findings of this study will allow for a better understanding of the prevalence and factors associated with analgesic use, pain and other outcomes in residential care. The findings of this study will be used to inform the development and implementation of strategies to improve the quality of life of people with dementia.

Prescribing opioids in older people

People are living to older age. Demographic pressures are driving change. Opiate analgesics are the most powerful known pain relievers. Persistent pain, both cancer and non-cancer types is frequent in older adults. The use of opioid analgesics is appropriate in the treatment of moderate to severe persistent pain. The challenge of prescribing opioids in older adults is to understand the factors involved in making appropriate choices and monitoring the beneficial effects of pain relief while managing the side-effects. This article will review the current concepts, evidence and controversies surrounding opiate use in the elderly. An approach is outlined which involves: pain assessment, screening for substance abuse potential, deciding whether you are able to treat your patient without help, starting treatment, monitoring effectiveness of pain control and managing opioid-associated side-effects. The goal of pain management using opioids is the attainment of improved function and quality of life.

Improving the pharmacologic management of pain in older adults: identifying the research gaps and methods to address them

OBJECTIVE

There has been a growing recognition of the need for better pharmacologic management of chronic pain among older adults. To address this need, the National Institutes of Health Pain Consortium sponsored an "Expert Panel Discussion on the Pharmacological Management of Chronic Pain in Older Adults" conference in September 2010 to identify research gaps and strategies to address them. Specific emphasis was placed on ascertaining gaps regarding use of opioid and nonsteroidal anti-inflammatory medications because of continued uncertainties regarding their risks and benefits.

DESIGN

Eighteen panel members provided oral presentations; each was followed by a multidisciplinary panel discussion. Meeting transcripts and panelists' slide presentations were reviewed to identify the gaps and the types of studies and research methods panelists suggested could best address them.

RESULTS

Fifteen gaps were identified in the areas of treatment (e.g., uncertainty regarding the long-term safety and efficacy of commonly prescribed analgesics), epidemiology (e.g., lack of knowledge regarding the course of common pain syndromes), and implementation (e.g., limited understanding of optimal strategies to translate evidence-based pain treatments into practice). Analyses of data from electronic health care databases, observational cohort studies, and ongoing cohort studies (augmented with pain and other relevant outcomes measures) were felt to be practical methods for building an age-appropriate evidence base to improve the pharmacologic management of pain in later life.

CONCLUSION

Addressing the gaps presented in the current report was judged by the panel to have substantial potential to improve the health and well-being of older adults with chronic pain.

Age-related changes in the hepatic pharmacology and toxicology of paracetamol

Optimal pharmacotherapy is determined when the pharmacokinetics and pharmacodynamics of the drug are understood. However, the age-related changes in pharmacokinetics and pharmacodynamics, as well as the increased interindividual variation mean optimal dose selection are a challenge for prescribing in older adults. Poor understanding of how hepatic clearance and toxicity are different with age results in suboptimal dose selection, poor efficacy, and/or increased toxicity. Of particular concern is the analgesic paracetamol which has been in use for more than 50 years and is consumed by a large proportion of older adults. Paracetamol is considered to be a relatively safe drug; however, caution must be taken because of its potential for toxicity. Paracetamol-induced liver injury from accidental overdose accounts for up to 55% of cases in older adults. Better understanding of how age affects the hepatic clearance and toxicity of drugs will contribute to evidence-based prescribing for older people, leading to fewer adverse drug reactions without loss of benefit.