Assessing cognition and psychomotor function under long-term treatment with controlled release oxycodone in non-cancer pain patients

Comparison of the Impacts of Under-Treated Pain and Opioid Pain Medication on Cognitive Impairment

Purpose: To guide clinicians in balancing the risks and benefits of opioids when treating pain, we conducted two systematic reviews: 1) the impact of pain on cognitive function, and 2) the impact of opioids on cognitive function.

Methods: Part one addressed the impact of pain on cognitive impairment; Part two considered the impact of opioids on cognitive impairment. PubMed was used to search for eligible articles. For part one, 1786 articles were identified, of which 23 met our eligibility criteria. For part two, among 584 articles, 18 were found eligible.

Results: For part one, 16 studies concluded that patients with chronic pain showed impaired cognitive function; six studies found that chronic pain does not worsen cognitive function; one study concluded that the impact of pain on cognitive function differs based on the underlying cognitive status. For part two, 15 studies found that using opioids to control pain did not cause significant cognitive impairment, while three studies concluded the opposite. Studies evaluating older subjects did not observe different results from those in the whole population for both reviews.

Conclusion: The published literature indicates that moderate to severe pain can impair cognitive function, and that careful use of opioid analgesics in such subjects does not necessarily worsen cognition. Although our results are insufficient to support clear guidance due to heterogeneity of cohorts and outcomes, this study may assist primary care providers by rendering explicitly the factors to be considered by providers caring for this population with pain when opioids are considered.

A Systematic Review and Meta-Analysis of Cognitive Performance among People with Chronic Use of Opioids for Chronic Non-Cancer Pain

OBJECTIVE

Opioids, often prescribed for chronic non-cancer pain, may adversely affect cognition. Research has not been synthesized in recent years, during which time academic interest has increased. This study presents meta-analyses on cognitive performance in people taking opioids for chronic non-cancer pain (CNCP).

METHODS

We ran systematic literature searches in EMBASE, Medline, and PsycINFO. Eligible studies included people taking opioids for CNCP, an opioid-free group (i.e., case-control) or session (e.g., pre-post), and objective cognitive assessments. Using random-effects meta-analyses, we computed pooled effect sizes for differential task performance for each study design across five domains (motor performance, attention, working memory, executive functions, memory).

RESULTS

Seventeen studies were included. Case-control studies covered three control types (healthy, CNCP, taper-off). Pre-post studies were grouped into five follow-ups (four to six and six to nine weeks; three, six, and 12 months). Effect sizes ranged from 0.02-0.62. Cases showed small magnitude impairments in attention and memory compared with healthy controls. Although limited by small sample sizes, there was no clear evidence of impairment in cases compared with opioid-free controls with CNCP. Cases showed some cognitive improvements from opioid-free baseline to follow-up. Effects were strongest for attention and working memory and were apparent from four weeks to six months follow-up. Other effects were small and nonsignificant.

CONCLUSIONS

Opioid therapy for CNCP did not worsen cognitive performance and improved it for some domains. People who take opioids for CNCP may evidence deficits in attention and memory, but this is unlikely to translate to global impairment and likely relates to pain more so than opioids.

Opioid Use and Driving Performance

INTRODUCTION

The USA is in an opioid epidemic, with an increased number of individuals taking psychoactive drugs while executing the tasks of everyday life, including operating a motor vehicle. The pharmacology of opioids has been widely studied, but the effects of opioids on psychomotor function, driving performance, and the risk of motor vehicle collision remain less clear. Clinicians are faced with the challenge of controlling patient pain while also reconciling conflicting messages from the literature about how safe it is for their patients taking opioids to engage in potentially dangerous routine tasks.

DISCUSSION

This review assesses the current literature regarding opioids as they relate to neurocognitive function, driving performance, and accident risk. Manuscripts are categorized by study context and subject matter: controlled experimental administration, illicit use, prescription use, retrospective forensic toxicology, and polydrug consumption.

CONCLUSION

Illicit use, initiation of therapy, and opioid use in combination with other psychoactive medications are contexts most clearly associated with impairment of driving-related functions and/or operation of a motor vehicle. Clinicians should counsel patients on the risk of impairment when initiating therapy, when co-prescribing opioids and other psychoactive drugs, or when a patient is suspected of having an opioid use disorder.

Cognitive Function During Opioid Tapering in Patients with Chronic Pain: A Prospective Cohort Study

Purpose

Evidence for efficacy and safety lacks for long-term opioid therapy in patients with chronic non-cancer pain and adverse effects, including affection of cognitive function and quality of life, is of concern. We aimed to investigate cognitive function and health-related quality of life in patients with chronic non-cancer pain during opioid reduction.

Patients and Methods

At two multidisciplinary pain centers, all patients with planned opioid reduction were screened for eligibility. Cognitive function was assessed using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and Trail Making Test A and B. Health-related quality of life was assessed using Short Form-36 (SF36) and Hospital Anxiety and Depression Scale (HADS).

Results

We included 51 participants and 40 participants attended follow-up of median 254 (IQR 106–357) days. Baseline RBANS score was 82 (IQR 65–93) with reference population norm value of 100 (SD±15). Daily opioid consumption was reduced from median 80 (IQR 45–161) oral morphine milligram equivalents to 19 (IQR 0–60) mg. RBANS score estimate increased by 6.2 (95% CI 3.1–9.3, p=0.0004) points after tapering. No differences were observed for Trail Making Test times, HADS or SF36 scores.

Conclusion

Generally, cognitive function showed minor improvement after opioid tapering with stationary health-related quality of life, depression and anxiety scores. The clinical significance is unclear, as no minimal clinically important difference in RBANS score is available.

Pain therapy - Are there new options on the horizon?

This article reviews the role of analgesic drugs with a particular emphasis on opioids. Opioids are the oldest and most potent drugs for the treatment of severe pain, but they are burdened by detrimental side effects such as respiratory depression, addiction, sedation, nausea, and constipation. Their clinical application is undisputed in acute (e.g., perioperative) and cancer pain, but their long-term use in chronic pain has met increasing scrutiny and has contributed to the current opioid crisis. We discuss epidemiological data, pharmacological principles, clinical applications, and research strategies aiming at novel opioids with reduced side effects.

Prescription opioids, alcohol and fatal motor vehicle crashes: a population-based case-control study

Background

The prevalence of prescription opioid use among drivers has increased markedly in the past two decades. The purpose of this study is to assess the associations of prescription opioid use and alcohol use with the risk of fatal crash involvement in US drivers.

Methods

We performed a population-based case-control study using toxicological testing data from two national data systems. Cases (n = 3606) were drivers involved in fatal motor vehicle crashes selected from the Fatality Analysis Reporting System and controls (n = 15,600) were drivers participating in the 2007 and 2013 National Roadside Surveys of Alcohol and Drug Use by Drivers. Multivariable logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs) of fatal crash involvement associated with prescription opioid use with and without the presence of alcohol.

Results

Overall, cases were significantly more likely than controls to test positive for prescription opioids (5.0% vs. 3.7%, p < 0.001), alcohol (56.2% vs. 7.1%, p < 0.0001), and both substances (2.2% vs. 0.2%, p < 0.001). Relative to drivers testing negative for prescription opioids and alcohol, the adjusted ORs of fatal crash involvement were 1.72 (95% CI: 1.37, 2.17) for those testing positive for prescription opioids and negative for alcohol, 17.92 (95% CI: 16.19, 19.84) for those testing positive for alcohol and negative for prescription opioids, and 21.89 (95% CI: 14.38, 33.32) for those testing positive for both substances. The interaction effect on fatal crash risk of prescription opioid use and alcohol use was not statistically significant on either additive or multiplicative scale.

Conclusions

Prescription opioid use is associated with a significantly increased risk of fatal crash involvement independently of alcohol use. Concurrent use of prescription opioids and alcohol is associated with a 21-fold increased risk of fatal crash involvement.

Correlation between Blood and Oral Fluid Psychoactive Drug Concentrations and Cognitive Impairment in Driving under the Influence of Drugs

BACKGROUND

The effects of drugs on driving performance should be checked with drug concentration in the brain and at the same time with the evaluation of both the behavioural and neurophysiological effects. The best accessible indicator of this information is the concentration of the drug and/or metabolites in blood and, to a certain extent, oral fluid. We sought to review international studies on correlation between blood and oral fluid drug concentrations, neurological correlates and cognitive impairment in driving under the influence of drugs.

METHODS

Relevant scientific articles were identified from PubMed, Cochrane Central, Scopus, Web of Science, Science Direct, EMBASE up to April 2017.

RESULTS

Up to 2010, no epidemiological studies were available on this matter and International scientists suggested that even minimal amounts of parent drugs in blood and oral fluid could affect driving impairment. More recently, epidemiological data, systematic reviews and meta-analysis on drugged drivers allowed the suggestion of impairment concentration limits for the most common illicit drugs. These values were obtained comparing driving disability induced by psychotropic drugs with that of established blood alcohol limits. Differently from ethyl alcohol where both detection methods and concentration limits have been well established even with inhomogeneity of ranges within different countries, in case of drugs of abuse no official cut-offs have yet been established, nor any standardized analytical protocols.

CONCLUSION

Multiple aspects of driving performance can be differently affected by illicit drugs, and even if for few of them some dose/concentration dependent impairment has been reported, a wider knowledge on concentration/impairment relationship is still missing.

Assessing the practice of palliative care doctors: what driving advice do they give patients with advanced disease?

BACKGROUND

There is little research and no clear guidelines for clinicians to follow when instructing patients with advanced disease about driving.

AIMS

To investigate current practice in providing advice to patients with advanced disease and identify areas of consensus or variation with the Australian driving guidelines.

METHODS

An online survey was distributed to Australian members of the Australian and New Zealand Society of Palliative Medicine. Responses were analysed using descriptive statistics.

RESULTS

The survey was distributed to 322 Australian and New Zealand Society of Palliative Medicine members and received 92 responses (29% response rate). Most respondents were aware of the driving guidelines (76%) and about half of the respondents had read the driving guidelines (55%). The majority of respondents had been asked to provide advice about driving to their patient or patient's caregiver (91%). Most respondents had asked a patient to stop driving (94%), but only 27% had reported a patient to the Driver Licensing Authority. Only 14% of respondents were in consensus with the guidelines in providing driving advice to a patient with asymptomatic brain metastases. Most doctors (64%) advise patients to refrain temporarily from driving post-short-acting oral morphine, with 4 h (36%) being the most common time period for not driving.

CONCLUSIONS

This is the first survey investigating the practice of Australian doctors in assessing fitness to drive of patients with advanced disease. The survey found wide variability in practice and substantial discordance with current driving guidelines.

Opiate Analgesics as Negative Modulators of Adult Hippocampal Neurogenesis: Potential Implications in Clinical Practice

During the past decade, studies of the mechanisms and functional implications of adult hippocampal neurogenesis (ahNG) have significantly progressed. At present, it is proposed that adult born neurons may contribute to a variety of hippocampal-related functions, including specific cognitive aspects and mood regulation. Several groups focussed on the factors that regulate proliferation and fate determination of adult neural stem/progenitor cells (NSC/NPC), including clinically relevant drugs. Opiates were the first drugs shown to negatively impact neurogenesis in the adult mammalian hippocampus. Since that initial report, a vast array of information has been collected on the effect of opiate drugs, by either modulating proliferation of stem/progenitor cells or interfering with differentiation, maturation and survival of adult born neurons. The goal of this review is to critically revise the present state of knowledge on the effect of opiate drugs on the different developmental stages of ahNG, as well as the possible underlying mechanisms. We will also highlight the potential impact of deregulated hippocampal neurogenesis on patients undergoing chronic opiate treatment. Finally, we will discuss the differences in the negative impact on ahNG among clinically relevant opiate drugs, an aspect that may be potentially taken into account to avoid long-term deregulation of neural plasticity and its associated functions in the clinical practice.

Development of a test for recording both visual and auditory reaction times, potentially useful for future studies in patients on opioids therapy

Objective

Italian Road Law limits driving while undergoing treatment with certain kinds of medication. Here, we report the results of a test, run as a smartphone application (app), assessing auditory and visual reflexes in a sample of 300 drivers. The scope of the test is to provide both the police force and medication-taking drivers with a tool that can evaluate the individual’s capacity to drive safely.

Methods

The test is run as an app for Apple iOS and Android mobile operating systems and facilitates four different reaction times to be assessed: simple visual and auditory reaction times and complex visual and auditory reaction times. Reference deciles were created for the test results obtained from a sample of 300 Italian subjects. Results lying within the first three deciles were considered as incompatible with safe driving capabilities.

Results

Performance is both age-related (r>0.5) and sex-related (female reaction times were significantly slower than those recorded for male subjects, P<0.05). Only 21% of the subjects were able to perform all four tests correctly.

Conclusion

We developed and fine-tuned a test called Safedrive that measures visual and auditory reaction times through a smartphone mobile device; the scope of the test is two-fold: to provide a clinical tool for the assessment of the driving capacity of individuals taking pain relief medication; to promote the sense of social responsibility in drivers who are on medication and provide these individuals with a means of testing their own capacity to drive safely.

Assessing Cognitive and Psychomotor Performance in Patients with Fibromyalgia Syndrome

Introduction

Patients with fibromyalgia syndrome (FMS) generally present with chronic widespread pain, accompanied by a range of additional and non-specific symptoms, such as fatigue, disturbed sleep, and cognitive dysfunction, which tend to increase with overall severity. Previous studies have shown moderate cognitive impairment in patients with FMS, but there are few valid data explicitly assessing the relevance of these findings to everyday functions, such as driving ability. Therefore, we studied patients with FMS to assess the impact of FMS on tests that predict driving ability.

Methods

Female patients with FMS were prospectively compared to a historical control group of healthy volunteers. The test battery comprised assessments of visual orientation, concentration, attention, vigilance, motor coordination, performance under stress, and reaction time.

Results

A total of 43 patients were matched to 129 controls. The results indicated that the patients’ psychomotor and cognitive performances were significantly non-inferior when compared to healthy controls (with 0.05% alcohol), with the exception of motor coordination. Patients and healthy controls showed an age-related decline in test performance. Correlations were smaller in patients and reversed for vigilance which was linked to a greater FMS symptom load in younger patients.

Conclusion

The results of the present study demonstrate that, in general, the driving ability of patients with FMS was not inferior to that of healthy volunteers based on a standardized computer-based test battery. However, variables, such as younger age, depression, anxiety, fatigue, pain, and poor motor coordination, likely contribute to the subjective perception of cognitive dysfunction in FMS.

Electronic supplementary material

The online version of this article (doi:10.1007/s40122-014-0028-0) contains supplementary material, which is available to authorized users.

Recombinant human growth hormone improves cognitive capacity in a pain patient exposed to chronic opioids

During recent decades, the increasing use of opioids for chronic non-cancer pain has raised concerns regarding tolerance, addiction, and importantly cognitive dysfunction. Current research suggests that the somatotrophic axis could play an important role in cognitive function. Administration of growth hormone (GH) to GH-deficient humans and experimental animals has been shown to result in significant improvements in cognitive capacity. In this report, a patient with cognitive disabilities resulting from chronic treatment with opioids for neuropathic pain received recombinant human growth hormone (rhGH) replacement therapy. A 61-year-old man presented with severe cognitive dysfunction after long-term methadone treatment for intercostal neuralgia and was diagnosed with GH insufficiency by GH releasing hormone-arginine testing. The effect of rhGH replacement therapy on his cognitive capacity and quality of life was investigated. The hippocampal volume was measured using magnetic resonance imaging, and the ratios of the major metabolites were calculated using proton magnetic resonance spectroscopy. Cognitive testing revealed significant improvements in visuospatial cognitive function after rhGH. The hippocampal volume remained unchanged. In the right hippocampus, the N-acetylaspartate/creatine ratio (reflecting nerve cell function) was initially low but increased significantly during rhGH treatment, as did subjective cognitive, physical and emotional functioning. This case report indicates that rhGH replacement therapy could improve cognitive behaviour and well-being, as well as hippocampal metabolism and functioning in opioid-treated patients with chronic pain. The idea that GH could affect brain function and repair disabilities induced by long-term exposure to opioid analgesia is supported.

Driving Ability in Patients with Severe Chronic Low Back or Osteoarthritis Knee Pain on Stable Treatment with Tapentadol Prolonged Release: A Multicenter, Open-label, Phase 3b Trial

Introduction

Strong centrally acting analgesics, including tapentadol prolonged release (PR), have demonstrated efficacy for the management of non-malignant, chronic pain. Maintaining patient independence, including the ability to drive safely, is a key goal of long-term analgesic therapy. This multicenter, open-label, phase 3b trial evaluated the effects of tapentadol PR on driving ability.

Methods

This study included patients who had completed previous tapentadol PR trials for severe low back or osteoarthritis pain. After at least 6 weeks of dose stability, patients continued taking tapentadol PR (50–250 mg twice daily) and could take supplemental immediate-release tapentadol 50 mg, except on the day before or day of the driving test (before the test). Pain intensity was assessed using an 11-point numerical rating scale. The Vienna Test System-Traffic Plus was used to assess cognitive and psychomotor function. The key surrogate parameter for driving ability was a global judgment based on 6 battery tests.

Results

Thirty-eight patients enrolled and completed the trial, and 35 patients completed all 6 tests. Pain scores remained unchanged from enrollment to final visit [mean (standard deviation) change, –0.2 (1.0)]. Approximately two-thirds [65.7% (23/35)] of patients were classified as fit to drive based on the global judgment of driving-specific ability [34.3% (12/35) not fit to drive]. Total daily tapentadol PR dose (>200 vs. ≤200 mg/day) did not affect global judgment of driving ability (P = 0.4885). Two adverse events (considered unrelated to study drug) were reported.

Conclusion

Results suggest that most patients receiving a stable dose of tapentadol PR for severe, chronic pain would be able to drive, consistent with earlier studies evaluating stable treatment with strong opioids. Study design limitations and needs for individual patient assessment must be considered in clinical practice.

Electronic supplementary material

The online version of this article (doi:10.1007/s40122-014-0025-3) contains supplementary material, which is available to authorized users.

Denying a patient's final will: public safety vs. medical confidentiality and patient autonomy

Especially when caring for patients approaching the end of life, physicians and nursing staff feel committed to fulfilling as many patient desires as possible. However, sometimes a patient's "final will" may threaten public safety. This can lead to severe conflicts, outweighing the physician's obligation and dedication to care for the patient and to respect his autonomy. Yet, public safety can be threatened if confidentiality is not broken. This article provides a concise summary of the medicolegal and ethical fundamentals concerning this difficult situation. If the patient's and others' health and safety are at risk, physicians may (and in some countries must) break medical confidentiality and disclose confidential patient information to the police and other authorities. Physicians should be able to professionally deal with such a conflict in all patients, not only in patients with advanced illness.

The impact of long-term maintenance treatment with buprenorphine on complex psychomotor and cognitive function

INTRODUCTION

Despite the fact that buprenorphine is effective, well tolerated and due to its pharmacological profile a very safe drug, the impact of long-term buprenorphine substitution therapy on complex psychomotor and cognitive function predicting driving ability is not yet clear. Therefore, a prospective comparison between patients receiving sublingual buprenorphine and a control group of untreated, healthy volunteers was performed.

METHODS

Treated and untreated subjects were matched for age and sex, with three control subjects selected for every buprenorphine patient. Patients using unreported drugs were included in the intention-to-treat (ITT) analysis; the remaining patients were analysed as the per-protocol (PP) group. The test battery comprised the assessment of: performance during stress, visual orientation, concentration, attention, vigilance and reaction time. The primary endpoint was defined as the sum of the relevant scores of the tests after z-transformation of the individual scores.

RESULTS

30 patients with sublingual buprenorphine treatment (7.7±3.9 mg per day) were matched to 90 controls. 19 patients were excluded from the PP-analysis because of additional unreported drug intake. Significant non-inferiority could be demonstrated for the PP-group (p<0.05) as well as for the ITT-group (p<0.001).

CONCLUSION

Patients receiving a stable dose of sublingual buprenorphine showed no significant impairment of complex psychomotor or cognitive performance as compared to healthy controls. However intake of illicit drugs as well as the lack of social reliability are major problems in this specific patients group. Despite of the absence of a relevant impact of the drug on driving ability, those patients do not seem to be qualified for getting their driving license.

Pharmacoeconomic impact of adverse events of long-term opioid treatment for the management of persistent pain

Opioids are the most powerful analgesic drugs currently available and consequently form an essential part of the treatment options for malignant and non-malignant chronic pain. However, the benefits of these medications can be offset by gastrointestinal adverse events such as nausea, vomiting and constipation, as well as adverse events affecting the CNS. These occur relatively frequently in patients receiving long-term opioids for pain relief and are a cause of additional patient suffering and reduced work and social functioning, measured as reductions in quality-of-life outcomes. Consequently, adverse events are often the cause of treatment non-compliance or discontinuation (non-persistence). A literature search was conducted using BIOSIS Previews, EMBASE, Cochrane Collaboration and MEDLINE databases to identify references with specific relevance to the measurement of health outcomes related to adverse events of long-term opioid treatment of chronic pain. The results of this search highlighted that clinical interventions required to manage adverse events associated with opioids, and to provide alternative methods of pain control, both incur direct costs. These are largely driven by the cost of medical consults and drug supplies. Indirect costs are generated from work absences and reduced social functioning. Estimated preference ratings, providing an insight into the trade-off between effective pain control and adverse events, have shown that utility decrements associated with an increase in adverse-event severity were similar in size to those caused by a shift from well controlled to poorly controlled pain. Given the rising prevalence of chronic pain conditions (affecting one in five adult Europeans), the direct and indirect costs incurred from the management of adverse events with long-term opioids are likely to be multiplied, contributing to the socioeconomic burden of chronic pain. For this reason, the adverse-event profile of opioid-based analgesics should be improved to achieve more efficient long-term pain control.

Current knowledge of buprenorphine and its unique pharmacological profile

Despite the increasing clinical use of transdermal buprenorphine, questions have persisted about the possibility of a ceiling effect for analgesia, its combination with other μ-opioid agonists, and the reversibility of side effects. In October 2008, a consensus group of experts met to review recent research into the pharmacology and clinical use of buprenorphine. The objective was to achieve consensus on the conclusions to be drawn from this work. It was agreed that buprenorphine clearly behaves as a full μ-opioid agonist for analgesia in clinical practice, with no ceiling effect, but that there is a ceiling effect for respiratory depression, reducing the likelihood of this potentially fatal adverse event. This is entirely consistent with receptor theory. In addition, the effects of buprenorphine can be completely reversed by naloxone. No problems are encountered when switching to and from buprenorphine and other opioids, or in combining them. Buprenorphine exhibits a pronounced antihyperalgesic effect that might indicate potential advantages in the treatment of neuropathic pain. Other beneficial properties are the compound's favorable safety profile, particularly in elderly patients and those with renal impairment, and its lack of effect on sex hormones and the immune system. The expert group agreed that these properties, as well as proven efficacy in severe pain and favorable tolerability, mean that buprenorphine can be considered a safe and effective option for treating chronic cancer and noncancer pain.

Pharmacoeconomic impact of adverse events of long-term opioid treatment for the management of persistent pain

Opioids are the most powerful analgesic drugs currently available and consequently form an essential part of the treatment options for malignant and non-malignant chronic pain. However, the benefits of these medications can be offset by gastrointestinal adverse events such as nausea, vomiting and constipation, as well as adverse events affecting the CNS. These occur relatively frequently in patients receiving long-term opioids for pain relief and are a cause of additional patient suffering and reduced work and social functioning, measured as reductions in quality-of-life outcomes. Consequently, adverse events are often the cause of treatment non-compliance or discontinuation (non-persistence). A literature search was conducted using BIOSIS Previews, EMBASE, Cochrane Collaboration and MEDLINE databases to identify references with specific relevance to the measurement of health outcomes related to adverse events of long-term opioid treatment of chronic pain. The results of this search highlighted that clinical interventions required to manage adverse events associated with opioids, and to provide alternative methods of pain control, both incur direct costs. These are largely driven by the cost of medical consults and drug supplies. Indirect costs are generated from work absences and reduced social functioning. Estimated preference ratings, providing an insight into the trade-off between effective pain control and adverse events, have shown that utility decrements associated with an increase in adverse-event severity were similar in size to those caused by a shift from well controlled to poorly controlled pain. Given the rising prevalence of chronic pain conditions (affecting one in five adult Europeans), the direct and indirect costs incurred from the management of adverse events with long-term opioids are likely to be multiplied, contributing to the socioeconomic burden of chronic pain. For this reason, the adverse-event profile of opioid-based analgesics should be improved to achieve more efficient long-term pain control.

Nabilone produces marked impairments to cognitive function and changes in subjective state in healthy volunteers

This was a double-blind, randomised, placebo-controlled, crossover study of the acute cognitive and subjective effects of nabilone 1-3 mg in healthy male volunteers. The Cognitive Drug Research computerised system (CDR system) was used to assess changes in attention, working and episodic memory. In addition, a number of self-ratings were conducted including those of mood, alertness and perceived drug effects. Impairments to attention, working and episodic memory and self-ratings of alertness were evident. Volunteers also experienced a number of subjective drug effects. These data demonstrate that acute doses of nabilone in the range 1-3 mg produce clear cognitive and subjective effects in healthy volunteers, and therefore they may be used as reference data in the future study of peripherally acting cannabinoids believed to be free from such effects.

Driving functions in a video simulator in chronic non-malignant pain patients using and not using codeine

BACKGROUND AND AIMS

A considerable number of Europeans suffer from chronic pain and are using opioids, particularly of the weak type. It is a clinical impression that many of these are driving or wish to drive a car. The aims of this study were to investigate if codeine influences driving ability in a simulator, and to examine if chronic pain per se might impair such functions.

METHODS

Twenty patients with chronic pain on long-term codeine therapy were compared to 20 chronic pain patients not using codeine in a video driving simulator test. The chronic pain patients were then compared to 20 healthy controls. The primary outcome measures were reaction time and number of missed reactions.

RESULTS

The patients using codeine 120-270 mg (mean 180 mg) daily showed the same driving skills as patients not using codeine, and the codeine level did not affect the results. This was the case both 1h after intake of a single dose of 60 mg codeine and five or more hours after the last codeine intake. The reaction times were significantly slower for the chronic pain patients, in both rural and urban driving conditions, compared to the healthy controls (difference 0.11s. and 0.12s., respectively). The chronic pain patients missed almost twice as many reactions to traffic signs. There were no difference between the groups in steering precision.

CONCLUSION

The main finding in this simulator study was that codeine does not impair driving-related abilities over and above what is associated with chronic pain per se.

The association between opioid analgesics and unsafe driving actions preceding fatal crashes

Currently, most epidemiological research into the impact of opioid analgesics on road safety has focused on the association between opioid use and traffic crash occurrence. Yet, the role of opioid analgesics on crash responsibility is still not properly understood. Therefore, we examined the impact of opioid analgesics on drivers (all had a confirmed BAC=0) involved in fatal crashes (1993-2006) using a case-control design based on data from the Fatality Analysis Reporting System. Cases had one or more crash-related unsafe driving actions (UDA) recorded; controls had none. We calculated adjusted odds ratios (ORs) of any UDA by medication exposure after controlling for age, sex, other medications, and driving record. Compared to drivers who tested negative for opioid analgesics, female drivers who tested positive demonstrated increased odds of performing an UDA from ages 25 (OR: 1.35; 95% CI: 1.05; 1.74) to 55 (OR: 1.30; 95% CI: 1.07; 1.58). For male drivers this was true from ages 25 (OR: 1.66; 95% CI: 1.32; 2.09) to 65 (OR: 1.39; 95% CI: 1.17; 1.67). The detection of opioid analgesics was not associated with greater risk of an UDA for older drivers. Research is necessary to examine why these age differences exist, and if possible, to ensure that opioid analgesics do not contribute to crashes.

Markers of abuse liability of short- vs long-acting opioids in chronic pain patients: a randomized cross-over trial

BACKGROUND

Abuse liability is thought to possibly be lower in long- than in short-acting opioids because lower peak serum levels may be less likely to induce psychoactive effects.

METHODS

We compared patient responses to extended-release morphine, hydrocodone plus acetaminophen, and placebo in a randomized, double-blind crossover study using markers of abuse liability. Patients indicated their craving for drugs on 5 visual analog scales (VASs), completed the Addiction Research Center Inventory, and underwent cue reactivity testing. To perform the latter, subjects watched a video intended to produce a positive or a negative affect, after which a vial of medication was or was not presented (the cue) and then indicated their craving for drugs on 5 different VASs (the reactivity).

RESULTS

Differences in Addiction Research Inventory scores were statistically significant but clinically unimportant. Neuropsychological test results were mixed and unrelated to the medications studied. Cue reactivity did not differ among conditions but was uniformly high.

CONCLUSIONS

Using several markers of abuse liability, long-acting opioids do not have lower abuse potential than do short-acting opioids or placebo. Although cue reactivity did not differ among the conditions, uniformly high results in these patients suggest that it may have some value as a component of abuse liability testing.

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.

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.

Opioids for nonmalignant pain

Pain is the most common symptom in the world for which patients seek professional help. Opioids offer an appropriate and safe treatment for some but not all patients with nonmalignant chronic pain. Potential risks, including drug abuse and intolerable side effects, appear to be manageable or even preventable in most cases. Patients with persistent rheumatic pain who have failed traditional treatments should be considered for long-acting opioids. Opioids are best administered in the framework of weighing the good against the bad in each patient, recognizing the potential morbidity and sometimes mortality in untreated patients who have severe and disabling pain daily.

Challenges in using opioids to treat pain in persons with substance use disorders

Pain and substance abuse co-occur frequently, and each can make the other more difficult to treat. A knowledge of pain and its interrelationships with addiction enhances the addiction specialist's efficacy with many patients, both in the substance abuse setting and in collaboration with pain specialists. This article discusses the neurobiology and clinical presentation of pain and its synergies with substance use disorders, presents methodical approaches to the evaluation and treatment of pain that co-occurs with substance use disorders, and provides practical guidelines for the use of opioids to treat pain in individuals with histories of addiction. The authors consider that every pain complaint deserves careful investigation and every patient in pain has a right to effective treatment.

Assessing cognitive and psychomotor performance under long-term treatment with transdermal buprenorphine in chronic noncancer pain patients

BACKGROUND

The therapeutic use of opioids has been associated with altered cognition and impaired psychomotor function. Several studies have demonstrated the impact of opioid therapy on psychomotor performance and cognition, but there are no data about the effect of long-term treatment with transdermal buprenorphine on driving ability.

METHODS

Thirty patients suffering from chronic noncancer pain, who had been treated with stable doses of transdermal buprenorphine, included in a prospective trial and compared with 90 healthy volunteers (matched pairs). A computerized test battery, developed to assess the driving ability of traffic delinquents in Germany, was used. Attention reaction, visual orientation, motor coordination, and vigilance were evaluated. The data from 14 variables were assessed, and for each test, a relevant score was defined. As the primary end-point, the sum score of the three relevant scores was determined. A weaker statistical means to assess the patient's performance is to compare the test results to an age-independent control group. Individuals performing worse than the 16th percentile of this control group are considered to be unable to drive according to German law.

RESULTS

According to tests that predict driving ability, patients receiving transdermal buprenorphine were shown to be noninferior to the control group. Driving ability, as defined as a result above the 16th percentile, did not differ significantly between the patients and the control group.

CONCLUSION

Long-term use of transdermal buprenorphine for chronic noncancer pain does not impair driving ability, but because of the individual variability of test results, an individual assessment is recommended.

Clinical use of opioids for cancer pain

Successful management of pain in the cancer patient requires careful assessment of the components of the pain complaint and accurate diagnosis of the cause of pain. Symptomatic management of pain involves pharmacotherapeutic strategies that focus on opioid use. Factors influencing the choice of opioid in patients with cancer pain include the severity of pain, the presence of coexisting disease, response to previous analgesic therapy, pharmacokinetic factors, available formulations, and patient compliance. Long-term opioid prescription always requires individual titration of medication to adequate pain relief, which is determined on an individual patient basis and/or based on manageable adverse effects. Failure to continuously monitor opioid use generally results in overtreatment or undertreatment of pain. The cognitive and psychomotor effects of long-term opioid therapy are not well-defined and merit further study.

Neuropsychological Consequences of Opiate Use

Approximately 3.7 million individuals have used heroin and other opiate substances in their lifetime. Despite increasing knowledge of the effects of heroin, it remains the most abused opiate and use among adults has recently increased. The empirical literature examining the neurocognitive effects of acute and chronic opioid use remains limited; however, findings to date suggest that the use of opiates has both acute and long-term effects on cognitive performance. Neuropsychological data indicate deficits in attention, concentration, recall, visuospatial skills and psychomotor speed with both acute and chronic opioid use. The long-term effects of opiate use appear to have the greatest impact on executive functions, including the ability to shift cognitive set and inhibit inappropriate response tendencies. Factors that contribute to addiction and recovery are also discussed, as it is difficult to disentangle the effects of opiate use on cognitive performance from other factors that may affect neurobehavioral measures.