The management of chronic pain in important patient subgroups

Comparison of the efficacy of auricular vagus nerve stimulation and conventional low back rehabilitation in patients with chronic low back pain

BACKGROUND

In recent years, human and animal studies have provided increasing evidence that vagus nerve stimulation (VNS) can produce analgesic effects as well as alleviating resistant epilepsy and depression. Our study was designed to compare the efficacy of transcutaneous auricular vagus nerve stimulation with conventional low back rehabilitation in patients with chronic low back pain (CLBP).

METHODS

Sixty patients with LBP were randomly divided into two groups. Group 1 received conventional rehabilitation and home exercise, and Group 2 received transcutaneous auricular VNS and home exercise. Both groups received treatment five days a week for three weeks. Trunk mobility (Modified Schober test, fingertip-to-floor test), muscle strength (CSMI-Cybex Humac-Norm isokinetic dynamometer and Lafayette manual muscle strength measuring device), trunk endurance, balance tests, Visual Analog Scale, Beck Depression Scale, Pittsburgh Sleep Quality Index, Oswestry Disability Index were evaluated.

RESULTS

At the end of three weeks, within-group assessment results showed positive effects on mobility, functional status, depression and sleep in all groups (p < 0.05). Pain level, endurance time and flexion trunk muscle strength results showed more improvement in Group 2 (p < 0.05). Some parameters of isokinetic lower extremity quadriceps muscle strength and fall risk scores showed a significant improvement in Group 1 (p < 0.05).

DISCUSSION

VNS has been observed to be more effective on pain, trunk muscle strength and endurance duration and sleep status. Auricular VNS may be included in the treatment of patients with CLBP in whom conventional physical therapy is inadequate or not applicable.

Role of Vagus Nerve Stimulation in the Treatment of Chronic Pain

Vagus nerve stimulation (VNS) can modulate vagal activity and neuro-immune communication. Human and animal studies have provided growing evidence that VNS can produce analgesic effects in addition to alleviating refractory epilepsy and depression. The vagus nerve (VN) projects to many brain regions related to pain processing, which can be affected by VNS. In addition to neural regulation, the anti-inflammatory property of VNS may also contribute to its pain-inhibitory effects. To date, both invasive and noninvasive VNS devices have been developed, with noninvasive devices including transcutaneous stimulation of auricular VN or carotid VN that are undergoing many clinical trials for chronic pain treatment. This review aimed to provide an update on both preclinical and clinical studies of VNS in the management for chronic pain, including fibromyalgia, abdominal pain, and headaches. We further discuss potential underlying mechanisms for VNS to inhibit chronic pain.

GPR171 activation regulates morphine tolerance but not withdrawal in a test-dependent manner in mice

A newly deorphanized G protein-coupled receptor, GPR171, is found to be highly expressed within the periaqueductal gray, a pain-modulating region in the brain. Our recent research has shown that a GPR171 agonist increases morphine antinociception in male mice and opioid signaling in vitro . The objective of this study was to evaluate the effects of combination treatment in females as well as whether chronic treatment can be used without exacerbating morphine-induced tolerance and withdrawal in female and male mice. Our results demonstrate that activation of GPR171 with an agonist attenuates morphine tolerance in both female and male mice on the tail-flick test, but not the hotplate test. Importantly, the GPR171 agonist in combination with morphine does not exacerbate morphine-induced tolerance and withdrawal during long-term morphine treatment. Taken together, these data suggest that the GPR171 agonist may be combined with morphine to maintain antinociception while reducing the dose of morphine and therefore reducing side effects and abuse liability. The outcome of this study is clearly an important step toward understanding the functional interactions between opioid receptors and GPR171 and developing safer therapeutics for long-term pain management.

Phenotypic drug screen uncovers the metabolic GCH1/BH4 pathway as key regulator of EGFR/KRAS-mediated neuropathic pain and lung cancer

Increased tetrahydrobiopterin (BH4) generated in injured sensory neurons contributes to increased pain sensitivity and its persistence. GTP cyclohydrolase 1 (GCH1) is the rate-limiting enzyme in the de novo BH4 synthetic pathway, and human single-nucleotide polymorphism studies, together with mouse genetic modeling, have demonstrated that decreased GCH1 leads to both reduced BH4 and pain. However, little is known about the regulation of Gch1 expression upon nerve injury and whether this could be modulated as an analgesic therapeutic intervention. We performed a phenotypic screen using about 1000 bioactive compounds, many of which are target-annotated FDA-approved drugs, for their effect on regulating Gch1 expression in rodent injured dorsal root ganglion neurons. From this approach, we uncovered relevant pathways that regulate Gch1 expression in sensory neurons. We report that EGFR/KRAS signaling triggers increased Gch1 expression and contributes to neuropathic pain; conversely, inhibiting EGFR suppressed GCH1 and BH4 and exerted analgesic effects, suggesting a molecular link between EGFR/KRAS and pain perception. We also show that GCH1/BH4 acts downstream of KRAS to drive lung cancer, identifying a potentially druggable pathway. Our screen shows that pharmacologic modulation of GCH1 expression and BH4 could be used to develop pharmacological treatments to alleviate pain and identified a critical role for EGFR-regulated GCH1/BH4 expression in neuropathic pain and cancer in rodents.

Immersive virtual reality to relieve exercise-induced pain caused by aerobic cycling

Chronic pain affects 20% of the global population and is incredibly complex to treat. The burden of chronic pain is physical, emotional and financial, and prevalence rates continue to rise. Current treatments are ineffective long-term against pain and common comorbidities, including anxiety and depression, mood and sleep disorders, and social isolation. While a large body of evidence supports regular physical exercise as an effective long-term treatment for chronic pain and its comorbidities, exercise-induced pain and kinesiophobia are significant barriers to participation and adherence. Immersive virtual reality is a powerful short-term pain reliever, that, when combined with exercise, can help overcome these barriers. This perspective argues for the use of combined exercise and virtual reality treatment techniques to mitigate chronic pain.

Spousal Care and Pain Among the Population Aged 65 Years and Older: A European Analysis

Background: Spousal care is the most important source of informal care in old age. Nevertheless, despite the growing importance of this issue, the association between providing spousal care inside the household and pain remains unexplored in Europe. Objective and Methods: This study aims to estimate the prevalence of pain reported by spouse caregivers aged 65 plus that provide care inside the household and to investigate the association between providing spousal care and pain. Data from 17 European countries that participated in wave 6 of the Survey of Health, Aging and Retirement in Europe (SHARE) is used. The analyses are based on 26,301 respondents aged 65 years and older who provide informal care inside the household to their spouse/partner exclusively (N = 1,895) or do not provide any informal care (inside or outside the household) (24,406). Descriptive statistics and multilevel logistic regressions (individual-level as level 1, and country as level 2) were performed. Results: Overall, spouse caregivers report pain more often (63.4%) than their non-caregiver's counterparts (50.3%). Important differences in the prevalence of pain among spouse caregivers were found between countries, with Portugal (80.3%), Spain (74.6%), France (73%), Italy (72.4%), and Slovenia (72.1) showing the highest prevalence of pain, and Denmark (36%), Switzerland (41.5) and Sweden (42.3%), the lowest. Results from multilevel logistic regressions show that European individuals aged 65+ who provide spousal care have an increased likelihood of reporting pain (OR 1.30; CI = 1.13-1.48). Conclusion: Our results suggest that in Europe, spouse caregivers aged 65+ are at greater risk of experiencing pain. Therefore, European policymakers should consider spouse caregivers as a health priority group, and take measures to ensure they receive comprehensive health and socio-economic support.

T Cells as Guardians of Pain Resolution

Despite successful research efforts aimed at understanding pain mechanisms, there is still no adequate treatment for many patients suffering from chronic pain. The contribution of neuroinflammation to chronic pain is widely acknowledged. Here, we summarize findings indicating that T cells play a key role in the suppression of pain. An active contribution of the immune system to resolution of pain may explain why immunosuppressive drugs are often not sufficient to control pain. This would also imply that dysregulation of certain immune functions promote transition to chronic pain. Conversely, stimulating the endogenous immune-mediated resolution pathways may provide a potent approach to treat chronic pain.

Can Medical Cannabis Therapies be Cost-Effective in the Non-Surgical Management of Chronic Knee Pain?

Introduction:

Chronic knee pain is a common musculoskeletal condition, which usually leads to decreased quality of life and a substantial financial burden. Various non-surgical treatments have been developed to relieve pain, restore function and delay surgical intervention. Research on the benefits of medical cannabis (MC) is emerging supporting its use for chronic pain conditions. The purpose of this study was to evaluate the cost-effectiveness of MC compared to current non-surgical therapies for chronic knee pain conditions.

Methods:

We conducted a cost-utility analysis from a Canadian, single payer perspective and compared various MC therapies (oils, soft gels and dried flowers at different daily doses) to bracing, glucosamine, pharmaceutical-grade chondroitin oral non-steroidal anti-inflammatory drugs (NSAIDs), and opioids. We estimated the quality-adjusted life years (QALYs) gained with each treatment over 1 year and calculated incremental cost-utility ratios (ICURs) using both the mean and median estimates for costs and utilities gained across the range of reported values. The final ICURs were compared to willingness-to-pay (WTP) thresholds of $66 714, $133 428 and $200 141 Canadian dollars (CAD) per QALY gained.

Results:

Regardless of the estimates used (mean or median), both MC oils and soft gels at both the minimal and maximal recommended daily doses were cost-effective compared to all current knee pain therapies at the lowest WTP threshold. Dried flowers were only cost-effective up to a certain dosage (0.75 and 1 g/day based on mean and median estimates, respectively), but all dosages were cost-effective when the WTP was increased to $133 428/QALY gained.

Conclusion:

Our study showed that MC may be a cost-effective strategy in the management of chronic knee pain; however, the evidence on the medical use of cannabis is limited and predominantly low-quality. Additional trials on MC are definitely needed, specifically in patients with chronic knee pain.

Evidence-based clinical practice guidelines on the management of pain in older people – a summary report

Objective:

The objective of this study is to develop an update of the evidence-based guidelines for the management of pain in older people.

Design:

Review of evidence since 2010 using a systematic and consensus approach is performed.

Results:

Recognition of the type of pain and routine assessment of pain should inform the use of specific environmental, behavioural and pharmacological interventions. Individualised care plans and analgesic protocols for specific clinical situations, patients and health care settings can be developed from these guidelines.

Conclusion:

Management of pain must be considered as an important component of the health care provided to all people, regardless of their chronological age or severity of illness. By clearly outlining areas where evidence is not available, these guidelines may also stimulate further research. To use the recommended therapeutic approaches, clinicians must be familiar with adverse effects of treatment and the potential for drug interactions.

Repurposing of Tranilast for Potential Neuropathic Pain Treatment by Inhibition of Sepiapterin Reductase in the BH4 Pathway

Tetrahydrobiopterin (BH₄) is a cofactor in the production of various signaling molecules including nitric oxide, dopamine, adrenaline, and noradrenaline. BH₄ levels are critical for processes associated with cardiovascular function, inflammation, mood, pain, and neurotransmission. Increasing pieces of evidence suggest that BH₄ is upregulated in chronic pain. Sepiapterin reductase (SPR) catalyzes both the reversible reduction of sepiapterin to dihydrobiopterin (BH₂) and 6-pyruvoyl-tetrahydrobiopterin to BH₄ within the BH₄ pathway. Therefore, inhibition of SPR by small molecules can be used to control BH₄ production and ultimately alleviate chronic pain. Here, we have used various in silico and in vitro experiments to show that tranilast, licensed for use in bronchial asthma, can inhibit sepiapterin reduction by SPR. Docking and molecular dynamics simulations suggest that tranilast can bind to human SPR (hSPR) at the same site as sepiapterin including S157, one of the catalytic triad residues of hSPR. Colorimetric assays revealed that tranilast was nearly twice as potent as the known hSPR inhibitor, N-acetyl serotonin. Tranilast was able to inhibit hSPR activity both intracellularly and extracellularly in live cells. Triple quad mass spectrophotometry of cell lysates showed a proportional decrease of BH₄ in cells treated with tranilast. Our results suggest that tranilast can act as a potent hSPR inhibitor and therefore is a valid candidate for drug repurposing in the treatment of chronic pain.

Pain incidence, assessment, and management in Vietnam: a cross-sectional study of 12,136 respondents

Objective

To describe the rate and demographics of pain among Vietnamese people in 48 provinces and describe the impact of pain on individuals, levels of satisfaction with treatment results, and behavior of pain sufferers.

Methods

The cross-sectional study was conducted in adults presenting to outpatient clinics throughout 48 provinces in Vietnam and were randomly selected for inclusion in this study. A physician trained to administer a questionnaire in a standardized fashion interviewed each patient and collected data regarding gender, age, career, acute and chronic pain, diagnoses, treatment, and satisfaction with treatment.

Results

There were 12,136 respondents (50.65% male and 49.35% female) from 48 of the 63 provinces in Vietnam. About 86.53% of respondents reported experiencing pain that affected their daily lives, with 24.10% complaining of acute pain and 62.43% having chronic pain. About 67.71% reported pain that affected job performance. Headache was the most common complaint in 35.43% of the respondents. Fewer than half (43.35%) of all patients with pain sought help from a doctor; only a quarter (27.50%) sought help within 1 month of experiencing that pain. A majority (61.98%) of patients who did seek help were satisfied with treatment results. The median cost of treatment was between 150 and 250 USD.

Conclusion

Pain severe enough to impact patients’ daily lives is common in Vietnam. Treatment costs are a significant economic burden and may help explain why only a minority of patients seek treatment. Access to lower cost, effective treatment for pain should be improved.

Review article: Effective management of opioid withdrawal symptoms: A gateway to opioid dependence treatment

BACKGROUND AND OBJECTIVES

The opioid crisis has taken an immense toll in the United States. On average, five lives are lost to an opioid overdose every hour of the day; estimated costs associated with opioid misuse exceed $500 billion annually. Illicit opioid discontinuation is the first step in the treatment of opioid use disorder (OUD), and transition to an opioid agonist may initiate treatment. However, discontinuation to abstinence from either OUD directly or following agonist treatment results in severely distressing opioid withdrawal symptoms (OWS).

METHODS

This review evaluated studies on the etiology, burden, and management of OWS.

RESULTS

Noradrenergic hyperactivity generates many OWS. These OWS can cause patients to relapse during early opioid discontinuation. While agonist therapies are generally first-line for moderate or severe OUD and reduce OWS, prescribing restrictions can limit their availability.

DISCUSSION AND CONCLUSIONS

Non-opioid medications to treat OWS provides a gateway into long-term treatment with naltrexone or psychosocial therapies. For opioid dependent patients without OUD, non-opioid treatments like α-2 adrenergic agonists can facilitate opioid tapering.

SCIENTIFIC SIGNIFICANCE

For the millions who are physically dependent on opioids, new treatments for OWS can enhance recovery from OUD and prevent relapse. (© 2019 The Authors. The American Journal on Addictions Published by Wiley Periodicals, Inc.;XX:1-8).

Paracetamol in Older People: Towards Evidence-Based Dosing?

Paracetamol is the most commonly used analgesic in older people, and is mainly dosed according to empirical dosing guidelines. However, the pharmacokinetics and thereby the effects of paracetamol can be influenced by physiological changes occurring with ageing. To investigate the steps needed to reach more evidence-based paracetamol dosing regimens in older people, we applied the concepts used in the paediatric study decision tree. A search was performed to retrieve studies on paracetamol pharmacokinetics and safety in older people (> 60 years) or studies that performed a (sub) analysis of pharmacokinetics and/or safety in older people. Of 6088 articles identified, 259 articles were retained after title and abstract screening. Further abstract and full-text screening identified 27 studies, of which 20 described pharmacokinetics and seven safety. These studies revealed no changes in absorption with ageing. A decreased (3.9-22.9%) volume of distribution (Vd) in robust older subjects and a further decreased Vd (20.3%) in frail older compared with younger subjects was apparent. Like Vd, age and frailty decreased paracetamol clearance (29-45.7 and 37.5%) compared with younger subjects. Due to limited and heterogeneous evidence, it was difficult to draw firm and meaningful conclusions on changed risk for paracetamol safety in older people. This review is a first step towards bridging knowledge gaps to move to evidence-based paracetamol dosing in older subjects. Remaining knowledge gaps are safety when using therapeutic dosages, pharmacokinetics changes in frail older people, and to what extent changes in paracetamol pharmacokinetics should lead to a change in dosage in frail and robust older people.

Divergent roles of immune cells and their mediators in pain

Chronic pain is a major debilitating condition that is difficult to treat. Although chronic pain may appear to be a disorder of the nervous system, crucial roles for immune cells and their mediators have been identified as important contributors in various types of pain. This review focuses on how the immune system regulates pain and discusses the emerging roles of immune cells in the initiation or maintenance of chronic pain. We highlight which immune cells infiltrate damaged nerves, the dorsal root ganglia, spinal cord and tissues around free nerve endings and discuss through which mechanisms they control pain. Finally we discuss emerging roles of the immune system in resolving pain and how the immune system contributes to the transition from acute to chronic pain. We propose that targeting some of these immune processes may provide novel therapeutic opportunities for the treatment of chronic pain.

The prevalence of pain and analgesia use in the Australian population: Findings from the 2011 to 2012 Australian National Health Survey

BACKGROUND

Opioid analgesic use and associated adverse events have increased over the last 15 years, including in Australia. Whether this is associated with increased chronic pain prevalence in the Australian population is unknown. This study aimed to estimate (1) the prevalence of chronic pain and analgesia use in the Australian population by age and sex; (2) the severity of pain in the population with chronic pain by sex; and (3) the distribution of recent pain severity in those using analgesia by age and sex.

METHODS

This study used cross-sectional, nationally representative data collected by the Australian Bureau of Statistics 2011 to 2012 National Health Survey. A total of n = 20 426 participants were included with an overall response rate of 84.8%. Weighting procedures were applied to obtain population estimates, confidence intervals, and when testing for statistical significance.

RESULTS

The prevalence of chronic and reoccurring pain (over a 6-month period) was 15.4% (2.75 million) for Australians aged ≥15 years. Prevalence increased with age for both sexes. Significantly more females reported moderate-to-very severe pain overall (P < 0.001), and within most age groups. Recent use of opioid analgesia was reported by 12.0% of males and 13.4% of females with chronic pain.

CONCLUSION

Chronic pain and opioid analgesic use are important public health issues in Australia. Study estimates of chronic pain and recent pain were no greater than earlier estimates. The acknowledged increase of opioid use in the literature thus appears consistent with changing treatment and/or prescribing patterns over time. Sex differences regarding pain prevalence, severity, and opioid use were apparent.

Pain rather than self-reported sedentary time explains variation in perceived health and activity limitation in persons with rheumatoid arthritis: a cross sectional study in Sweden

To investigate (1) the amount of self-reported time spent sedentary among a large cohort of persons with rheumatoid arthritis (RA), and (2) the contribution of sedentary time to explain perceived health and activity limitation in RA beyond that of previously known correlates. This cross-sectional study used data from a postal questionnaire and the Swedish Rheumatology Quality registers (SRQ). The International Physical Activity Questionnaire was used to assess sedentary time (sitting) and moderate, vigorous and walking activity (MVPA). Sociodemographics, pain, fatigue, fear-avoidance beliefs, anxiety/depression, disease duration, MVPA and sedentary time were included in multiple regression models with perceived health (Visual Analogue Scale 0-100) and activity limitation (Stanford Health Assessment Questionnaire) as dependent variables.

RESULTS

In all 3152 (59%) of 5391 persons identified as eligible from the SRQ, responded to the questionnaire. 2819 individuals with complete data on all study variables were analysed. Mean time (SD) spent sedentary was 257 (213) minutes per day. Sedentary time did not contribute significantly to explain perceived health and only minimally to explain activity limitation. Instead, variation was mainly explained by pain; for perceived health (Beta = 0.780, p < 0.001) and for activity limitation (Beta = 0.445, p < 0.001).The results indicate a non-significant role of sedentary time and a need for increased focus on pain in the management of RA. Future studies should use prospective designs and objective assessment methods to further investigate the associations between sedentary time and health outcomes in persons with RA.

Opioids Resistance in Chronic Pain Management

Chronic pain management represents a serious healthcare problem worldwide. Chronic pain affects approximately 20% of the adult European population and is more frequent in women and older people. Unfortunately, its management in the community remains generally unsatisfactory and rarely under the control of currently available analgesics. Opioids have been used as analgesics for a long history and are among the most used drugs; however, while there is no debate over their short term use for pain management, limited evidence supports their efficacy of long-term treatment for chronic non-cancer pain. Therapy with opioids is hampered by inter-individual variability and serious side effects and some opioids often result ineffective in the treatment of chronic pain and their use is controversial. Accordingly, for a better control of chronic pain a deeper knowledge of the molecular mechanisms underlying resistance to opiates is mandatory.

Opioid receptor agonists may favorably affect bone mechanical properties in rats with estrogen deficiency-induced osteoporosis

The results of epidemiological, clinical, and in vivo and in vitro experimental studies on the effect of opioid analgesics on bone are inconsistent. The aim of the present study was to investigate the effect of morphine (an agonist of opioid receptors), buprenorphine (a partial μ opioid receptor agonist and κ opioid receptor antagonist), and naloxone (an antagonist of opioid receptors) on the skeletal system of female rats in vivo. The experiments were carried out on 3-month-old Wistar rats, divided into two groups: nonovariectomized (intact; NOVX) rats and ovariectomized (OVX) rats. The bilateral ovariectomy was performed 7 days before the start of drug administration. Morphine hydrochloride (20 mg/kg/day s.c.), buprenorphine (0.05 mg/kg/day s.c.), or naloxone hydrochloride dihydrate (2 mg/kg/day s.c.) were administered for 4 weeks to NOVX and OVX rats. In OVX rats, the use of morphine and buprenorphine counteracted the development of osteoporotic changes in the skeletal system induced by estrogen deficiency. Morphine and buprenorphine beneficially affected also the skeletal system of NOVX rats, but the effects were much weaker than those in OVX rats. Naloxone generally did not affect the rat skeletal system. The results confirmed the role of opioid receptors in the regulation of bone remodeling processes and demonstrated, in experimental conditions, that the use of opioid analgesics at moderate doses may exert beneficial effects on the skeletal system, especially in estrogen deficiency.

The impact of pain on systemic rheumatic diseases

Pain is associated with the different types of rheumatic syndromes because it is often the most troubling symptom of patients affected by any of these diseases. Some risk factors clearly play a major role in the clinical expression of pain and related syndromes, including genetics, age, gender, co-morbidities, traumas and psychological patterns, but there are no specific clinical, laboratory or neuroimaging markers that can indicate why and when a patient's localised pain will become chronic and widespread. Any type of pain must be treated not only appropriately, but also rapidly because the likelihood of developing some form of chronic pain is related to the duration of the peripheral pain stimulus. Chronic pain inevitably has a major impact on patients' quality of life because the loss of function undermines their ability to do everyday activities. Pain can be most effectively treated by carefully selecting various pharmacological and non-pharmacological interventions based on the characteristics of the pain itself, disease factors, psychological coping abilities, and lifestyle.

Activation of P2X7 receptors in the midbrain periaqueductal gray of rats facilitates morphine tolerance

Opiates such as morphine exhibit analgesic effect in various pain models, but repeated and chronic morphine administration may develop resistance to antinociception. The purinergic signaling system is involved in the mechanisms of pain modulation and morphine tolerance. This study aimed to determine whether the P2X7 receptor in the ventrolateral midbrain periaqueductal gray (vlPAG) is involved in morphine tolerance. Development of tolerance to the antinociceptive effect of morphine was induced in normal adult male Sprague-Dawley (SD) rats through subcutaneous injection of morphine (10mg/kg). The analgesic effect of morphine (5mg/kg, i.p.) was assessed by measuring mechanical withdrawal thresholds (MWTs) in rats with an electronic von Frey anesthesiometer. The expression levels and distribution of the P2X7 receptor in the vlPAG was evaluated through Western blot analysis and immunohistochemistry. The acute effects of intra-vlPAG injection of the selective P2X7 receptor agonist Bz-ATP, the selective P2X7 receptor antagonist A-740003, or antisense oligodeoxynucleotide (AS ODN) targeting the P2X7 receptor on morphine-treated rats were also observed. Results demonstrated that repeated morphine administration decreased the mechanical pain thresholds. By contrast, the expression of the P2X7 receptor protein was up-regulated in the vlPAG in morphine tolerant rats. The percent changes in MWT were markedly but only transiently attenuated by intra-vlPAG injection of Bz-ATP (9nmol/0.3μL) but elevated by A-740003 at doses of 10 and 100nmol/0.3μL. AS ODN (15nmol/0.3μL) against the P2X7 receptor reduced the development of chronic morphine tolerance in rats. These results suggest that the development of antinociceptive tolerance to morphine is partially mediated by activating the vlPAG P2X7 receptors. The present data also suggest that the P2X7 receptors may be a therapeutic target for improving the analgesic effect of morphine in treatments of pain when morphine tolerance occurs.

Osteoporosis and fragility fractures: Vertebral fractures

The incidence of vertebral fragility fractures and deformity increase steeply with age. Every sixth woman and every twelfth man will sustain a symptomatic vertebral fracture. Vertebral fractures result in pain, functional disability and decreased quality of life, which may last for several years, and may also affect mortality. The patient with an acute fracture should be examined with radiology for diagnosis. In case of a low-energy fracture, osteoporosis should be suspected and investigated. If the pain management fails, vertebroplasty or kyphoplasty could be considered. Braces may be used, but evidence for its effect is lacking. In the rare event of neurological compromise, or unstable fractures, surgical treatment should be considered. After vertebral fragility fractures, the risk for new fractures is high and secondary preventive measures advocated. The best evidence for secondary prevention is currently on medical treatment of osteoporosis.

Opioid use for Chronic Pain Management in Italy: Results from the Orthopedic Instant Pain Survey Project

Pain is a common symptom in orthopedic patients, but is managed sub-optimally, partly due to scarce opioid use in severe cases. The aim of the Orthopedic Instant Pain Survey (POIS) was to evaluate changes in pain management in Italian orthopedic practice 2 years after a legislative change (Law 38/2010) simplifying opioid access for pain control. A web-based survey on the knowledge of this law and trends observed in clinical practice for severe pain treatment was administered to 143 Italian orthopedic specialists. In total, 101 (70%) respondents showed a high level of knowledge. Nevertheless, 54.5% stated that they do not use opioids for severe osteo-articular pain management. Main barriers to opioid use are fear of adverse events (61.4%), especially nausea/vomiting and constipation, and patient resistance (29.7%). A modest knowledge of pain classification was also demonstrated. Opioid use remains very limited in Italian orthopedic practice. Physicians’ fear of side effects showed poor knowledge of strategies for effective management of opioid-related adverse events, such as combined oral prolonged-release oxycodone/naloxone. Continuing educational programs could improve delivery of evidence-based pain management.

Evaluation of the effect of D-002, a mixture of beeswax alcohols, on osteoarthritis symptoms

BACKGROUND/AIMS

Nonsteroidal anti-inflammatory drugs relieve osteoarthritis (OA) symptoms but cause adverse effects. D-002, a mixture of beeswax alcohols, is effective against experimental OA. A pilot study found that D-002 (50 mg/day) for 8 weeks improves OA symptoms. The aim of this study was to investigate the effects of D-002 (50 to 100 mg/day) administered for 6 weeks on OA symptoms.

METHODS

Patients with OA symptoms were double-blindly randomized to D-002 (50 mg) or placebo for 6 weeks. Symptoms were assessed by the Western Ontario and McMaster Individual Osteoarthritis Index (WOMAC) and the visual analog scale (VAS) scores. Patients without symptom improvement at week 3 were titrated to two daily tablets. The primary outcome was the total WOMAC score. WOMAC pain, joint stiffness and physical function scores, VAS score, and use of rescue medications were secondary outcomes.

RESULTS

All randomized patients (n = 60) completed the study, and 23 experienced dose titration (two in the D-002 and 21 in the placebo groups). At study completion, D-002 reduced total WOMAC (65.4%), pain (54.9%), joint stiffness (76.8%), and physical function (66.9%) WOMAC scores, and the VAS score (46.8%) versus placebo. These reductions were significant beginning in the second week, and became enhanced during the trial. The use of rescue medication by the D-002 (6/30) group was lower than that in the placebo (17/30) group. The treatment was well tolerated. Seven patients (two in the D-002 and five in the placebo group) reported adverse events.

CONCLUSIONS

These results indicate that D-002 (50 to 100 mg/day) for 6 weeks ameliorated arthritic symptoms and was well tolerated.

Immunoglobulin g for the treatment of chronic pain: report of an expert workshop

BACKGROUND

The treatment of chronic pain is still unsatisfactory. Despite the availability of different drugs, most patients with chronic pain do not receive satisfactory pain relief or report side effects. Converging evidence implicates involvement of the immune system in the pathogenesis of different types of nociceptive and neuropathic chronic pain.

DESIGN

At a workshop in Liverpool, UK (October 2012), experts presented evidence suggesting immunological involvement in chronic pain and recent data supporting the concept that the established immune-modulating drug, polyvalent immunoglobulin G (IgG), either given intravenously (IVIg) or subcutaneously (SCIg), may reduce pain in some peripheral neuropathies and a range of other pain disorders. Workshop's attendees discussed the practicalities of using IVIg and SCIg in these disorders, including indications, cost-effectiveness, and side effects.

RESULTS

IgG may reduce pain in a range of nociceptive and neuropathic chronic pain conditions, including diabetes mellitus, Sjögren's syndrome, fibromyalgia, complex regional pain syndrome, post-polio syndrome, and pain secondary to pathological autoantibodies.

CONCLUSIONS

IgG is a promising treatment in several chronic pain conditions. IgG is a relatively safe therapeutic strategy, with uncommon and mild side effects but high costs. Randomized, controlled trials and predictive tests are needed to better support the use of IgG for refractory chronic pain.