Transdermal fentanyl reduces pain and improves functional activity in neuropathic pain states

An Overview of Recent Developments in the Management of Burn Injuries

According to the World Health Organization (WHO), around 11 million people suffer from burns every year, and 180,000 die from them. A burn is a condition in which heat, chemical substances, an electrical current or other factors cause tissue damage. Burns mainly affect the skin, but can also affect deeper tissues such as bones or muscles. When burned, the skin loses its main functions, such as protection from the external environment, pathogens, evaporation and heat loss. Depending on the stage of the burn, the patient's condition and the cause of the burn, we need to choose the most appropriate treatment. Personalization and multidisciplinary collaboration are key to the successful management of burn patients. In this comprehensive review, we have collected and discussed the available treatment options, focusing on recent advances in topical treatments, wound cleansing, dressings, skin grafting, nutrition, pain and scar tissue management.

Targeting Chemokines and Chemokine GPCRs to Enhance Strong Opioid Efficacy in Neuropathic Pain

Neuropathic pain (NP) originates from an injury or disease of the somatosensory nervous system. This heterogeneous origin and the possible association with other pathologies make the management of NP a real challenge. To date, there are no satisfactory treatments for this type of chronic pain. Even strong opioids, the gold-standard analgesics for nociceptive and cancer pain, display low efficacy and the paradoxical ability to exacerbate pain sensitivity in NP patients. Mounting evidence suggests that chemokine upregulation may be a common mechanism driving NP pathophysiology and chronic opioid use-related consequences (analgesic tolerance and hyperalgesia). Here, we first review preclinical studies on the role of chemokines and chemokine receptors in the development and maintenance of NP. Second, we examine the change in chemokine expression following chronic opioid use and the crosstalk between chemokine and opioid receptors. Then, we examine the effects of inhibiting specific chemokines or chemokine receptors as a strategy to increase opioid efficacy in NP. We conclude that strong opioids, along with drugs that block specific chemokine/chemokine receptor axis, might be the right compromise for a favorable risk/benefit ratio in NP management.

Intensive Daily Symptom and Function Monitoring Is Feasible and Acceptable to Women Undergoing First-Line Chemotherapy for Gynecologic Cancer

BACKGROUND

Women receiving chemotherapy for gynecologic cancer (GC) experience severe symptoms with associated functional changes. Understanding day-to-day symptom and function variation within and across chemotherapy treatment cycles could inform improved symptom management, but such studies are rare and may be infeasible in clinical care.

OBJECTIVE

The aim of this study was to evaluate feasibility and acceptability of daily symptom monitoring combined with objective and self-reported functional assessments every 21 days during active chemotherapy for GC.

METHODS

Thirty women enrolled in a prospective observational study during first-line chemotherapy completed a daily symptom and falls diary during their entire chemotherapy treatment period. Patient-reported outcomes and objective symptom and function testing were assessed before each chemotherapy appointment. Study outcomes included accrual and attrition rates, completion of study assessments, and qualitative perceptions of study participation.

RESULTS

Participants were 92% White, 60% had high school or higher education, 68% were married/partnered, and 62% had stage III or IV cancer at diagnosis. The study had an 83% accrual rate, 6.6% early withdrawal rate, and 17% total attrition rate. Missing assessments for prechemotherapy patient-reported outcomes and objective assessments ranged from 27% to 35% and 35% to 47% respectively, with a general decrease across cycles. Daily diary completion rate was 83% overall. Participants rated study participation positively.

CONCLUSIONS

Intensive daily symptom and function monitoring was feasible and acceptable to GC patients and may provide a sense of symptom controllability.

IMPLICATIONS FOR PRACTICE

Daily symptom and function monitoring in research studies may provide patients with information to support symptom discussions with the clinical team. Future work should develop proactive symptom management interventions using personalized symptom trajectories.

A Review on Mechanistic and Pharmacological Findings of Diabetic Peripheral Neuropathy including Pharmacotherapy

BACKGROUND

Chronic hyperglycemia and related complications involving peripheral nerves in diabetes are one of the most severe microvascular complications with an average prevalence of 50-60%. Diabetic neuropathy is among the vascular disorders of diabetes, the most debilitating and crippled, lethal condition impacting patients's quality of life.

METHODS

In the present review article, several hypotheses associated with the pathogenesis of Diabetic Peripheral Neuropathy (DPN) have been introduced, among them metabolic pathways associated with polyol pathway, oxidative stress, production of reactive oxygen species (ROS) amplified under chronic hyperglycemic conditions and activation of transcription factor Nuclear factor-κB (NF- κB). The review article also possesses pathogenetic and pharmacologic treatments along with others, including acupressure, lidocaine, and capsaicin for DPN.

CONCLUSION

It may be concluded that we can combat the pathogenesis of DPN with different suggested treatments.

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.

Drug-specific differences in the ability of opioids to manage burn pain

Burn injury pain is a significant public health problem. Burn injury treatment has improved tremendously in recent decades. However, an unintended consequence is that a larger number of patients now survive more severe injuries, and face intense pain that is very hard to treat. Although many efforts have been made to find alternative treatments, opioids remain the most effective medication available. Burn patients are frequently prescribed opioids in doses and durations that are significantly higher and longer than standard analgesic dosing guidelines. Despite this, many continue to experience unrelieved pain. They are also placed at a higher risk for developing dependence and opioid use disorder. Burn injury profoundly alters the functional state of the immune system. It also alters the expression levels of receptor, effector, and signaling molecules within the spinal cord's dorsal horn. These alterations could explain the reduced potency of opioids. However, recent studies demonstrate that different opioids signal preferentially via differential signaling pathways. This ligand-specific signaling by different opioids implies that burn injury may reduce the antinociceptive potency of opioids to different degrees, in a drug-specific manner. Indeed, recent findings hint at drug-specific differences in the ability of opioids to manage burn pain early after injury, as well as differences in their ability to prevent or treat the development of chronic and neuropathic pain. Here we review the current state of opioid treatment, as well as new findings that could potentially lead to opioid-based pain management strategies that may be significantly more effective than the current solutions.

Assessing Physical Activity and Sleep in Axial Spondyloarthritis: Measuring the Gap

Patients with axial spondyloarthritis (axSpA) frequently report pain, stiffness, fatigue, and sleep problems, which may lead to impaired physical activity. The majority of reported-on measures evaluating physical activity and sleep disturbance in axSpA are self-reported questionnaires, which can be impacted by patient recall (reporting bias). One objective measure, polysomnography, has been employed to evaluate sleep in patients with axSpA; however, it is an intrusive measure and cannot be used over the long term. More convenient objective measures are therefore needed to allow for the long-term assessment of both sleep and physical activity in patients' daily lives. Wearable technology that utilizes actigraphy is increasingly being used for the objective measurement of physical activity and sleep in various therapy areas, as it is unintrusive and suitable for continuous tracking to allow longitudinal assessment. Actigraphy characterizes sleep disruption as restless movement while sleeping, which is particularly useful when studying conditions such as axSpA in which chronic pain and discomfort due to stiffness may be evident. Studies have also shown that actigraphy can effectively assess the impact of disease on physical activity. More research is needed to establish the usefulness of objective monitoring of sleep and physical activity specifically in axSpA patients over time. This review summarizes the current perspectives on physical activity and sleep quality in patients with axSpA, and the possible role of actigraphy in the future to more accurately evaluate the impact of treatment interventions on sleep and physical activity in axSpA.Funding: Novartis Pharmaceuticals Corporation.Plain Language Summary: Plain language summary available for this article.

Assessment of physical function and participation in chronic pain clinical trials: IMMPACT/OMERACT recommendations

Although pain reduction is commonly the primary outcome in chronic pain clinical trials, physical functioning is also important. A challenge in designing chronic pain trials to determine efficacy and effectiveness of therapies is obtaining appropriate information about the impact of an intervention on physical function. The Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) and Outcome Measures in Rheumatology (OMERACT) convened a meeting to consider assessment of physical functioning and participation in research on chronic pain. The primary purpose of this article is to synthesize evidence on the scope of physical functioning to inform work on refining physical function outcome measurement. We address issues in assessing this broad construct and provide examples of frequently used measures of relevant concepts. Investigators can assess physical functioning using patient-reported outcome (PRO), performance-based, and objective measures of activity. This article aims to provide support for the use of these measures, covering broad aspects of functioning, including work participation, social participation, and caregiver burden, which researchers should consider when designing chronic pain clinical trials. Investigators should consider the inclusion of both PROs and performance-based measures as they provide different but also important complementary information. The development and use of reliable and valid PROs and performance-based measures of physical functioning may expedite development of treatments, and standardization of these measures has the potential to facilitate comparison across studies. We provide recommendations regarding important domains to stimulate research to develop tools that are more robust, address consistency and standardization, and engage patients early in tool development.

Fentanyl for neuropathic pain in adults

BACKGROUND

Opioid drugs, including fentanyl, are commonly used to treat neuropathic pain, and are considered effective by some professionals. Most reviews have examined all opioids together. This review sought evidence specifically for fentanyl, at any dose, and by any route of administration. Other opioids are considered in separate reviews.

OBJECTIVES

To assess the analgesic efficacy of fentanyl for chronic neuropathic pain in adults, and the adverse events associated with its use in clinical trials.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and Embase from inception to June 2016, together with the reference lists of retrieved articles, and two online study registries.

SELECTION CRITERIA

We included randomised, double-blind studies of two weeks' duration or longer, comparing fentanyl (in any dose, administered by any route, and in any formulation) with placebo or another active treatment in chronic neuropathic pain.

DATA COLLECTION AND ANALYSIS

Two review authors independently searched for studies, extracted efficacy and adverse event data, and examined issues of study quality and potential bias. We did not carry out any pooled analyses. We assessed the quality of the evidence using GRADE.

MAIN RESULTS

Only one study met our inclusion criteria. Participants were men and women (mean age 67 years), with postherpetic neuralgia, complex regional pain syndrome, or chronic postoperative pain. They were experiencing inadequate relief from non-opioid analgesics, and had not previously taken opioids for their neuropathic pain. The study used an enriched enrolment randomised withdrawal design. It was adequately blinded, but we judged it at unclear risk of bias for other criteria.Transdermal fentanyl (one-day fentanyl patch) was titrated over 10 to 29 days to establish the maximum tolerated and effective dose (12.5 to 50 µg/h). Participants who achieved a prespecified good level of pain relief with a stable dose of fentanyl, without excessive use of rescue medication or intolerable adverse events ('responders'), were randomised to continue with fentanyl or switch to placebo for 12 weeks, under double-blind conditions. Our prespecified primary outcomes were not appropriate for this study design, but the measures reported do give an indication of the efficacy of fentanyl in this condition.In the titration phase, 1 in 3 participants withdrew because of adverse events or inadequate pain relief, and almost 90% experienced adverse events. Of 258 participants who underwent open-label titration, 163 were 'responders' and entered the randomised withdrawal phase. The number of participants completing the study (and therefore continuing on treatment) without an increase of pain by more than 15/100 was 47/84 (56%) with fentanyl and 28/79 (35%) with placebo. Because only 63% responded sufficiently to enter the randomised withdrawal phase, this implies that only a maximum of 35% of participants entering the study would have had useful pain relief and tolerability with transdermal fentanyl, compared with 22% with placebo. Almost 60% of participants taking fentanyl were 'satisfied' and 'very satisfied' with their treatment at the end of the study, compared with about 40% with placebo. This outcome approximates to our primary outcome of moderate benefit using the Patient Global Impression of Change scale, but the group was enriched for responders and the method of analysis was not clear. The most common adverse events were constipation, nausea, somnolence, and dizziness.There was no information about other types of neuropathic pain, other routes of administration, or comparisons with other treatments.We downgraded the quality of the evidence to very low because there was only one study, with few participants and events, and there was no information about how data from people who withdrew were analysed.

AUTHORS' CONCLUSIONS

There is insufficient evidence to support or refute the suggestion that fentanyl works in any neuropathic pain condition.

Chronic pain treatment with opioid analgesics: benefits versus harms of long-term therapy

Chronic non-cancer pain (CNCP) is a disabling chronic condition with a high prevalence rate around the world. Opioids are routinely prescribed for treatment of chronic pain (CP). In the past two decades there has been a massive increase in the number of opioid prescriptions, prescribed daily opioid doses and overall opioid availability. Many more patients with CNCP receive high doses of long-acting opioids on a long-term basis. Yet CP and related disability rates remain high, and majority of the patients with CNCP are dissatisfied with their treatments. Intersecting with the upward trajectory in opioid use are the increasing trends in opioid related adverse effects, especially prescription drug abuse, addiction and overdose deaths. This complex situation raises questions on the relevance of opioid therapy in the treatment of CNCP. This article reviews current evidence on opioid effectiveness, the benefits and harms of long-term therapy in CNCP.

Thermal sensitivity across ages and during chronic fentanyl administration in rats

RATIONALE

Chronic pain is becoming a more common medical diagnosis and is especially prevalent in older individuals. As such, prescribed use of opioids is on the rise, even though the efficacy for pain management in older individuals is unclear.

OBJECTIVES

Thus, the present preclinical study assessed the effectiveness of chronic fentanyl administration to produce antinociception in aging rats (16, 20, and 24 months).

METHODS

Animals were tested in a thermal sensitivity procedure known to involve neural circuits implicated in chronic pain in humans. Sensitivity to heat and cold thermal stimulation was assessed during 28 days of fentanyl administration (1.0 mg/kg/day), and 28 days of withdrawal.

RESULTS

Fentanyl resulted in decreased thermal sensitivity to heat but not cold stimulation indicated by more time spent in the hot compartment relative to time spent in the cold or neutral compartments. Unlike previous findings using a hot-water tail withdrawal procedure, tolerance did not develop to the antinociceptive effects of fentanyl over a 28-day period of drug administration. The oldest animals were least sensitive, and the youngest animals most sensitive to the locomotor-stimulating effects of fentanyl. The effect on the antinociceptive response to fentanyl in the oldest group of rats was difficult to interpret due to profound changes in the behavior of saline-treated animals.

CONCLUSIONS

Overall, aging modifies the behavioral effects of opioids, a finding that may inform future studies for devising appropriate treatment strategies.

Modulating pain in the periphery: gene-based therapies to enhance peripheral opioid analgesia: Bonica lecture, ASRA 2010

This article provides a brief overview of earlier work of our group on the peripheral signaling of pain, summarizes more recent studies on the role of opioids in chronic neuropathic pain, and speculates on the future of gene-based therapies as novel strategies to enhance the peripheral modulation of pain. Neurophysiologic and psychophysical studies have revealed features of primary afferent activity from somatic tissue that led to improved understanding of the physiology and pathophysiology of pain signaling by nociceptive and nonnociceptive fibers. The demonstration of peripheral opioid mechanisms in neuropathic pain suggests a potential role for these receptors in the modulation of pain at its initiation site. Our work has focused on characterizing this peripheral opioid analgesia in chronic neuropathic pain such that it can be exploited to develop novel and potent peripheral analgesics for its treatment. Ongoing research on virus-mediated gene transfer strategies to enhance peripheral opioid analgesia is presented.

Efficient assessment of efficacy in post-traumatic peripheral neuropathic pain patients: pregabalin in a randomized, placebo-controlled, crossover study

Background:

Detecting the efficacy of novel analgesic agents in neuropathic pain is challenging. There is a critical need for study designs with the desirable characteristics of assay sensitivity, low placebo response, reliable pain recordings, low cost, short duration of exposure to test drug and placebo, and relevant and recruitable population.

Methods:

We designed a proof-of-concept, double-blind, randomized, placebo-controlled, crossover study in patients with post-traumatic peripheral neuropathic pain (PTNP) to evaluate whether such a study design had the potential to detect efficacious agents. Pregabalin, known to be efficacious in neuropathic pain, was used as the active analgesic. We also assessed physical activity throughout the study.

Results:

Twenty-five adults (20–70 years of age) with PTNP for ≥3 months entered a screening week and were then randomized to one of the two following treatment sequences: (1) pregabalin followed by placebo or (2) placebo followed by pregabalin. These 2-week treatment periods were separated by a 2-week washout period. Patients on pregabalin treatment received escalating doses to a final dosage of 300 mg/day (days 5–15). In an attempt to minimize placebo response, patients received placebo treatment during the screening week and the 2-week washout period. Average daily pain scores (primary endpoint) were significantly reduced for pregabalin versus placebo, with a mean treatment difference of −0.81 (95% confidence interval: −1.45 to −0.17; P = 0.015).

Conclusion:

The efficacy of pregabalin was similar to that identified in a large, parallel group trial in PTNP. Therefore, this efficient crossover study design has potential utility for future proof-of-concept studies in neuropathic pain.

Evaluation of efficacy and safety of fentanyl transdermal patch (Durogesic D-TRANS) in chronic pain

PURPOSE

Opioids are used in controlling several types of pain. This study was designed to evaluate the efficacy and safety of the fentanyl transdermal patch-type system (Durogesic® D-TRANS).

METHODS

Patients who complained of chronic moderate to severe pain were enrolled. Administration dosages of fentanyl patch started from 12.5 μg/h and could be increased by 12.5 μg/h or 25 μg/h, if the average pain score of 4 or higher occurred within 72 h. The total administration period was 12 weeks. The type, location, characteristics, and duration of pain were evaluated. Also, on day 0, weeks of 4, 8, and 12, the physician's assessment of pain intensity, the patient's assessment of pain intensity, the assessment of impact of pain on functions, and the assessment of the impact of pain on sleep were assessed. In addition, side effects were evaluated during the study duration.

RESULTS

A total of 65 cases were enrolled, and the final evaluated cases were 41. Before treatment, the average physician's assessment of pain intensity was 6.70 ± 1.41, and the average patient's assessment of pain intensity was 7.02 ± 1.63. In the final visit, the average physician's assessment of pain intensity was 2.58 ± 1.72, and the average patient's assessment of pain intensity was 2.86 ± 1.78.

CONCLUSIONS

This prospective study shows that the fentanyl patch is effective in alleviating moderate to severe chronic noncancer pain including neuropathic pain down to mild pain. Therefore, the fentanyl patch should be considered before other invasive intervention procedures in chronic moderate to severe noncancer pain.

Effects of chronic fentanyl administration on physical performance of aged rats

There is growing concern over the increasing use of opioids to treat chronic pain in the elderly primarily because of the potential increased sensitivity to the adverse side effects. Here, we use a preclinical model (male Brown Norway X F344 rats aged 12, 18, 24, and 30 months) to describe the outcome of chronic fentanyl administration (1.0mg/kg/day) on various physiological and behavioral measures. Continuous fentanyl administration resulted in an initial decrease in food consumption, followed by the development of tolerance to this effect over a 4-week period and a subsequent increase in food consumption during withdrawal. This change in food consumption was associated with decreases in body weight (predominantly due to a loss of fat mass) that was maintained through early withdrawal. After 1 month of withdrawal, only the 12-month old animals had fully regained body weight. Fentanyl administration resulted in a decrease in grip strength and an increase in locomotor activity that did not differ across age groups. There was no effect of fentanyl administration on rotarod performance. These results demonstrate that while there is a delayed recovery of body mass with age, the observed changes in behavioral responses are uniform across ages.

Formulations of fentanyl for the management of pain

Fentanyl is an opioid initially developed for parenteral administration. While oral administration is not an option due to a high first-pass metabolism, its high potency and lipophilicity have made a number of new routes of administration feasible. The transdermal therapeutic system offers an excellent option for long-term treatment of cancer and chronic pain, achieving stable plasma concentrations over the treatment period. The recent change from reservoir to matrix systems has made these systems more convenient to wear and safer to use, while being bioequivalent. In contrast, the patient-controlled iontophoretic transdermal system has been developed to enable on-demand delivery of transdermal bolus doses of fentanyl to treat postoperative pain. It offers a needle-free system to provide patient-controlled analgesia otherwise offered by intravenous pumps. However, due to technical difficulties the system is currently not clinically available. Oral transmucosal fentanyl utilizes the rapid uptake through the buccal mucosa to achieve high plasma concentrations rapidly and is indicated to treat breakthrough pain in patients who are not opioid-naive. The recently introduced fentanyl buccal tablets offer slightly better pharmacokinetics for the same indication. The intranasal route is another option to achieve rapid uptake of fentanyl, and is currently being investigated to provide acute and breakthrough pain relief. Transpulmonary administration of fentanyl remains experimental and this route of administration is not yet in clinical use. Overall, the specific pharmacological and physicochemical properties of fentanyl have made this compound highly suitable for novel routes of administration in a range of clinical indications.

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.

Neuropathic pain: quality-of-life impact, costs and cost effectiveness of therapy

A number of different diseases or injuries can damage the central or peripheral nervous system and produce neuropathic pain (NP), which seems to be more difficult to treat than many other types of chronic pain. As a group, patients with NP have greater medical co-morbidity burden than age- and sex-adjusted controls, which makes determining the humanistic and economic burden attributable to NP challenging. Health-related quality of life (HR-QOL) is substantially impaired among patients with NP. Patients describe pain-related interference in multiple HR-QOL and functional domains, as well as reduced ability to work and reduced mobility due to their pain. In addition, the spouses of NP patients have been shown to experience adverse social consequences related to NP. In randomized controlled trials, several medications have been shown to improve various measures of HR-QOL. Changes in HR-QOL appear to be tightly linked to pain relief, but not to the development of adverse effects. However, in cross-sectional studies, many patients continue to have moderate or severe pain and markedly impaired HR-QOL, despite taking medications prescribed for NP. The quality of NP treatment appears to be poor, with few patients receiving recommended medications in efficacious dosages. The substantial costs to society of NP derive from direct medical costs, loss of the ability to work, loss of caregivers' ability to work and possibly greater need for institutionalization or other living assistance. No single study has measured all of these costs to society for chronic NP. The cost effectiveness of various interventions for the treatment or prevention of different types of NP has been assessed in several different studies. The most-studied diseases are post-herpetic neuralgia and painful diabetic neuropathy, for which tricyclic antidepressants (both amitriptyline and desipramine) have been found to be either cost effective or dominant relative to other strategies. Increasing the use of cost-effective therapies such as tricyclic antidepressants for post-herpetic neuralgia and painful diabetic neuropathy may improve the HR-QOL of patients and decrease societal costs. Head-to-head clinical trials comparing NP therapies are needed to help assess the relative clinical efficacy of treatments, ideally using HR-QOL and utility outcomes. The full costs to society of NP, including productivity loss costs, have not been determined for chronic NP. Improved relative efficacy, utility and cost estimates would facilitate future cost-effectiveness research in NP.

Current management of pain associated with multiple sclerosis

While pain is a common problem in patients with multiple sclerosis (MS), it is not frequently mentioned by patients and a more direct approach is required in order to obtain information about pain from patients. Many patients with MS experience more than one pain syndrome; combinations of dysaesthesia, headaches and/or back or muscle and joint pain are frequent. For each pain syndrome a clear diagnosis and therapeutic concept needs to be established. Pain in MS can be classified into four diagnostically and therapeutically relevant categories: (i) neuropathic pain due to MS (pain directly related to MS); (ii) pain indirectly related to MS; (iii) MS treatment-related pain; and (iv) pain unrelated to MS. Painful paroxysmal symptoms such as trigeminal neuralgia (TN), or painful tonic spasms are treated with antiepileptics as first choice, e.g. carbamazepine, oxcarbazepine, lamotrigine, gabapentin, pregabalin, etc. Painful 'burning' dysaesthesias, the most frequent chronic pain syndrome, are treated with TCAs such as amitriptyline, or antiepileptics such as gabapentin, pregabalin, lamotrigine, etc. Combinations of drugs with different modes of action can be particularly useful for reducing adverse effects. While escalation therapy may require opioids, there are encouraging results from studies regarding cannabinoids, but their future role in the treatment of MS-related pain has still to be determined. Pain related to spasticity often improves with adequate physiotherapy. Drug treatment includes antispastic agents such as baclofen or tizanidine and in patients with phasic spasticity, gabapentin or levetiracetam are administered. In patients with severe spasticity, botulinum toxin injections or intrathecal baclofen merit consideration. While physiotherapy may ameliorate malposition-induced joint and muscle pain, additional drug treatment with paracetamol (acetaminophen) or NSAIDs may be useful. Moreover, painful pressure lesions should be avoided by using optimally adjusted aids. Treatment-related pain associated with MS can occur with subcutaneous injections of interferon-beta or glatiramer acetate, and may be reduced by optimizing the injection technique and by local cooling. Systemic (particularly 'flu-like') adverse effects of interferons, e.g. myalgias, can be reduced by administering paracetamol, ibuprofen or naproxen. A potential increase in the frequency of pre-existing headaches after starting treatment with interferons may require optimization of headache attack therapy or even prophylactic treatment. Pain unrelated to MS, such as back pain or headache, is common in patients with MS and may deteriorate as a result of the disease. In summary, a careful analysis of each pain syndrome will allow the design of the appropriate treatment plan using various medical and nonmedical options (multimodal therapy), and will thus help to improve the quality of life (QOL) of the patients.