Gary A. Walco

Recommendations for the Pharmacological Management of Neuropathic Pain: An Overview and Literature Update

The Neuropathic Pain Special Interest Group of the International Association for the Study of Pain recently sponsored the development of evidence-based guidelines for the pharmacological treatment of neuropathic pain. Tricyclic antidepressants, dual reuptake inhibitors of serotonin and norepinephrine, calcium channel alpha(2)-delta ligands (ie, gabapentin and pregabalin), and topical lidocaine were recommended as first-line treatment options on the basis of the results of randomized clinical trials. Opioid analgesics and tramadol were recommended as second-line treatments that can be considered for first-line use in certain clinical circumstances. Results of several recent clinical trials have become available since the development of these guidelines. These studies have examined botulinum toxin, high-concentration capsaicin patch, lacosamide, selective serotonin reuptake inhibitors, and combination therapies in various neuropathic pain conditions. The increasing number of negative clinical trials of pharmacological treatments for neuropathic pain and ambiguities in the interpretation of these negative trials must also be considered in developing treatment guidelines. The objectives of the current article are to review the Neuropathic Pain Special Interest Group guidelines for the pharmacological management of neuropathic pain and to provide a brief overview of these recent studies.

Core outcome domains and measures for pediatric acute and chronic/recurrent pain clinical trials: PedIMMPACT recommendations

UNLABELLED Under the auspices of the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT), 26 professionals from academia, governmental agencies, and the pharmaceutical industry participated in a 2-stage Delphi poll and a consensus meeting that identified core outcome domains and measures that should be considered in clinical trials of treatments for acute and chronic pain in children and adolescents. Consensus was refined by consultation with the international pediatric pain community through announcement of our recommendations on the Pediatric Pain List and inviting and incorporating comments from external sources. There was consensus that investigators conducting pediatric acute pain clinical trials should consider assessing outcomes in pain intensity; global judgment of satisfaction with treatment; symptoms and adverse events; physical recovery; emotional response; and economic factors. There was also agreement that investigators conducting pediatric clinical trials in chronic and recurrent pain should consider assessing outcomes in pain intensity; physical functioning; emotional functioning; role functioning; symptoms and adverse events; global judgment of satisfaction with treatment; sleep; and economic factors. Specific measures or measurement strategies were recommended for different age groups for each domain. PERSPECTIVE Based on systematic review and consensus of experts, core domains and measures for clinical trials to treat pain in children and adolescents were defined. This will assist in comparison and pooling of data and promote evidence-based treatment, encourage complete reporting of outcomes, simplify the review of proposals and manuscripts, and facilitate clinicians making informed decisions regarding treatment.

Summary Proceedings From the Neonatal Pain-Control Group

Recent advances in neurobiology and clinical medicine have established that the fetus and newborn may experience acute, established, and chronic pain. They respond to such noxious stimuli by a series of complex biochemical, physiologic, and behavioral alterations. Studies have concluded that controlling pain experience is beneficial with respect to short-term and perhaps long-term outcomes. Yet, pain-control measures are adopted infrequently because of unresolved scientific issues and lack of appreciation for the need for control of pain and its long-term sequelae during the critical phases of neurologic maturation in the preterm and term newborn. The neonatal pain-control group, as part of the Newborn Drug Development Initiative (NDDI) Workshop I, addressed these concerns. The specific issues addressed were (1) management of pain associated with invasive procedures, (2) provision of sedation and analgesia during mechanical ventilation, and (3) mitigation of pain and stress responses during and after surgery in the newborn infant. The cross-cutting themes addressed within each category included (1) clinical-trial designs, (2) drug prioritization, (3) ethical constraints, (4) gaps in our knowledge, and (5) future research needs. This article provides a summary of the discussions and deliberations. Full-length articles on procedural pain, sedation and analgesia for ventilated infants, perioperative pain, and study designs for neonatal pain research were published in Clinical Therapeutics (June 2005).

Neuropathic pain in children: Special considerations.

Neuropathic pain is relatively uncommon in children. Although some syndromes closely resemble those found in adults, the incidence and course of the condition can vary substantially in children, depending on developmental status and contextual factors. There are some neuropathic pain syndromes that are rare and relatively unique to the pediatric population. This article discusses the array of neuropathic pain conditions in children and available treatment strategies. Data are limited by small numbers and few randomized controlled trials. Research and clinical implications are discussed.

Procedural distress in children with cancer: self-report, behavioral observations, and physiological parameters.

Objectives:To examine the relationship among different indicators of pain and distress, including self-report, behavioral observations, and physiological parameters, in children with cancer undergoing invasive procedures. Methods:Forty-eight children between the ages of 3.1 and 17.7 years were evaluated while undergoing lumbar punctures. Self-report measures assessed anxiety, pain, self-efficacy, expectations of coping strategies, and coping self-efficacy. Parents reported on their own and their childs levels of anxiety, and physicians estimated their own level of stress and technical difficulty in completing the procedure. Behavioral observations were made prior to, during, and after the procedure. Physiological parameters included heart rate, cardiac vagal tone, and salivary cortisol. At the discretion of attending physicians, 32 children received deep sedation, 9 received light sedation, and 7 received cognitive-behavioral strategies with topical anesthetic as interventions to manage procedural distress. Results:There was a high degree of consistency within self-report, behavioral, and physiological parameters, but correlations between measures in different modalities were low. There were floor effects for most behavioral and self-report measures of distress. Cortisol showed marked changes preprocedure to postprocedure, demonstrating high levels of physiological response despite lack of apparent or perceived discomfort. Heart rate was significantly lower in the group using cognitive-behavioral techniques, especially at the point of needle insertion. Discussion:Self-report measures, behavioral indicators, and physiological changes are not interchangeable outcomes. Treatment strategies were effective for minimizing subjective and behavioral distress, but not necessarily for physiological reactions. Future research should focus on individual differences in these responses, and treatment outcome studies aimed at reducing distress must be clear about the specific goals of intervention.

Pediatric Analgesic Clinical Trial Designs, Measures, and Extrapolation: Report of an FDA Scientific Workshop

Analgesic trials pose unique scientific, ethical, and practical challenges in pediatrics. Participants in a scientific workshop sponsored by the US Food and Drug Administration developed consensus on aspects of pediatric analgesic clinical trial design. The standard parallel-placebo analgesic trial design commonly used for adults has ethical and practical difficulties in pediatrics, due to the likelihood of subjects experiencing pain for extended periods of time. Immediate-rescue designs using opioid-sparing, rather than pain scores, as a primary outcome measure have been successfully used in pediatric analgesic efficacy trials. These designs maintain some of the scientific benefits of blinding, with some ethical and practical advantages over traditional designs. Preferred outcome measures were recommended for each age group. Acute pain trials are feasible for children undergoing surgery. Pharmacodynamic responses to opioids, local anesthetics, acetaminophen, and nonsteroidal antiinflammatory drugs appear substantially mature by age 2 years. There is currently no clear evidence for analgesic efficacy of acetaminophen or nonsteroidal antiinflammatory drugs in neonates or infants younger than 3 months of age. Small sample designs, including cross-over trials and N of 1 trials, for particular pediatric chronic pain conditions and for studies of pain and irritability in pediatric palliative care should be considered. Pediatric analgesic trials can be improved by using innovative study designs and outcome measures specific for children. Multicenter consortia will help to facilitate adequately powered pediatric analgesic trials.

Treatment of chronic pain in pediatric rheumatic disease

Pain in children with rheumatic disease is common, and is most often caused by arthritis. Despite the widespread use of effective new biologic agents, pain continues to be a problem in these patients, and it greatly impairs their daily functioning and quality of life. The pathogenesis of pain in children with rheumatic diseases is multifactorial, and disease treatment alone is often not enough to alleviate it. No standard of care or detailed algorithm for managing pain in these patients exists. Specific pain treatments often include acetaminophen, NSAIDs and medications that treat arthritis, such as methotrexate and etanercept. Other approaches should include nonpharmacologic interventions, for example exercise and cognitive-behavioral therapy, as well as the use of analgesics such as opioids in patients whose pain is refractory to standard therapies. The use of systemic corticosteroids to treat pain in children with arthritis should be avoided.

Research design considerations for chronic pain prevention clinical trials: IMMPACT recommendations

Abstract Although certain risk factors can identify individuals who are most likely to develop chronic pain, few interventions to prevent chronic pain have been identified. To facilitate the identification of preventive interventions, an IMMPACT meeting was convened to discuss research design considerations for clinical trials investigating the prevention of chronic pain. We present general design considerations for prevention trials in populations that are at relatively high risk for developing chronic pain. Specific design considerations included subject identification, timing and duration of treatment, outcomes, timing of assessment, and adjusting for risk factors in the analyses. We provide a detailed examination of 4 models of chronic pain prevention (ie, chronic postsurgical pain, postherpetic neuralgia, chronic low back pain, and painful chemotherapy-induced peripheral neuropathy). The issues discussed can, in many instances, be extrapolated to other chronic pain conditions. These examples were selected because they are representative models of primary and secondary prevention, reflect persistent pain resulting from multiple insults (ie, surgery, viral infection, injury, and toxic or noxious element exposure), and are chronically painful conditions that are treated with a range of interventions. Improvements in the design of chronic pain prevention trials could improve assay sensitivity and thus accelerate the identification of efficacious interventions. Such interventions would have the potential to reduce the prevalence of chronic pain in the population. Additionally, standardization of outcomes in prevention clinical trials will facilitate meta-analyses and systematic reviews and improve detection of preventive strategies emerging from clinical trials.

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

Abstract 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.

Developing a standardized approach to the assessment of pain in children and youth presenting to pediatric rheumatology providers: a Delphi survey and consensus conference process followed by feasibility testing

BackgroundPain in children with rheumatic conditions such as arthritis is common. However, there is currently no standardized method for the assessment of this pain in children presenting to pediatric rheumatologists. A more consistent and comprehensive approach is needed to effectively assess, treat and monitor pain outcomes in the pediatric rheumatology population. The objectives of this study were to: (a) develop consensus regarding a standardized pain assessment tool for use in pediatric rheumatology practice and (b) test the feasibility of three mediums (paper, laptop, and handheld-based applications) for administration.MethodsIn Phase 1, a 2-stage Delphi technique (pediatric rheumatologists and allied professionals) and consensus meeting (pediatric pain and rheumatology experts) were used to develop the self- and proxy-report pain measures. In Phase 2, 24 children aged 4-7 years (and their parents), and 77 youth, aged 8-18 years, with pain, were recruited during routine rheumatology clinic appointments and completed the pain measure using each medium (order randomly assigned). The participants rheumatologist received a summary report prior to clinical assessment. Satisfaction surveys were completed by all participants. Descriptive statistics were used to describe the participant characteristics using means and standard deviations (for continuous variables) and frequencies and proportions (for categorical variables)ResultsCompleting the measure using the handheld device took significantly longer for youth (M = 5.90 minutes) and parents (M = 7.00 minutes) compared to paper (M = 3.08 and 2.28 minutes respectively p = 0.001) and computer (M = 3.40 and 4.00 minutes respectively; p < 0.001). There was no difference in the number of missed responses between mediums for children or parents. For youth, the number of missed responses varied across mediums (p = 0.047) with the greatest number of missed responses occurring with the handheld device. Most children preferred the computer (65%, p = 0.008) and youth reported no preference between mediums (p = 0.307). Most physicians (60%) would recommend the computer summary over the paper questionnaire to a colleague.ConclusionsIt is clinically feasible to implement a newly developed consensus-driven pain measure in pediatric rheumatology clinics using electronic or paper administration. Computer-based administration was most efficient for most users, but the medium employed in practice may depend on child age and economic and administrative factors.