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 a 2 -d 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.Mayo Clin Proc. 2010;85(3)(suppl):S3-S14 DPN = diabetic peripheral neuropathy; HIV = human immunodeficiency virus; HRQoL = health-related quality of life; NeuPSIG = Neuropathic Pain Special Interest Group; NP = neuropathic pain; PHN = postherpetic neuralgia; RCT = randomized clinical trial; SSNRI = selective serotonin norepinephrine reuptake inhibitor; SSRI = selective serotonin reuptake inhibitor; TCA = tricyclic antidepressant

Current approaches to classification of chronic pain conditions suffer from the absence of a systematically implemented and evidence-based taxonomy. Moreover, existing diagnostic approaches typically fail to incorporate available knowledge regarding the biopsychosocial mechanisms contributing to pain conditions. To address these gaps, the Analgesic, Anesthetic, and Addiction Clinical Trial Translations Innovations Opportunities and Networks (ACTTION) public-private partnership with the US Food and Drug Administration and the American Pain Society (APS) have joined together to develop an evidence-based chronic pain classification system called the ACTTION-APS Pain Taxonomy (AAPT). This manuscript describes the outcome of an ACTTION-APS consensus meeting, at which experts agreed on a structure for this new taxonomy of chronic pain conditions. Several major issues around which discussion revolved are presented and summarized, and the structure of the taxonomy is presented. AAPT will include the following Dimensions: 1) Core Diagnostic Criteria, 2) Common Features, 3) Common Medical Comorbidities, 4) Neurobiological, Psychosocial and Functional Consequences, and 5) Putative Neurobiological and Psychosocial Mechanisms, Risk Factors & Protective Factors. In coming months, expert working groups will apply this taxonomy to clusters of chronic pain conditions, thereby developing a set of diagnostic criteria that have been consistently and systematically implemented across nearly all common chronic pain conditions. It is anticipated that the availability of this evidence-based and mechanistic approach to pain classification will be of substantial benefit to chronic pain research and treatment. Perspective The ACTTION-APS Pain Taxonomy is an evidence-based chronic pain classification system designed to classify chronic pain along the following Dimensions: 1) Core Diagnostic Criteria, 2) Common Features, 3) Common Medical Comorbidities, 4) Neurobiological, Psychosocial and Functional Consequences, and 5) Putative Neurobiological and Psychosocial Mechanisms, Risk Factors & Protective Factors.

Cannabinoids, cannabis, and cannabis-based medicines (CBMs) are increasingly used to manage pain, with limited understanding of their efficacy and safety. We summarised efficacy and adverse events (AEs) of these types of drugs for treating pain using randomised controlled trials: in people of any age, with any type of pain, and for any treatment duration. Primary outcomes were 30% and 50% reduction in pain intensity, and AEs. We assessed risk of bias of included studies, and the overall quality of evidence using GRADE. Studies of <7 and >7 days treatment duration were analysed separately. We included 36 studies (7217 participants) delivering cannabinoids (8 studies), cannabis (6 studies), and CBM (22 studies); all had high and/or uncertain risk of bias. Evidence of benefit was found for cannabis <7 days (risk difference 0.33, 95% confidence interval 0.20-0.46; 2 trials, 231 patients, very low-quality evidence) and nabiximols >7 days (risk difference 0.06, 95% confidence interval 0.01-0.12; 6 trials, 1484 patients, very low-quality evidence). No other beneficial effects were found for other types of cannabinoids, cannabis, or CBM in our primary analyses; 81% of subgroup analyses were negative. Cannabis, nabiximols, and delta-9-tetrahydrocannabinol had more AEs than control. Studies in this field have unclear or high risk of bias, and outcomes had GRADE rating of low- or very low-quality evidence. We have little confidence in the estimates of effect. The evidence neither supports nor refutes claims of efficacy and safety for cannabinoids, cannabis, or CBM in the management of pain.

Clinically apparent cerebral edema is a rare and often fatal complication of diabetic ketoacidosis. To determine whether subclinical brain swelling occurs more commonly, we obtained cranial CT scans in six children with diabetic ketoacidosis treated with fluid resuscitation and continuous low-dose insulin therapy. Control scans were obtained before hospital discharge. Compared with the scans during convalescence, the early scans of all six children showed a narrowing of the brain's ventricular system, compatible with brain swelling. Average changes in diameter were 1.3 +/- 0.1 mm for the third ventricle and 3.7 +/- 0.8 mm for the lateral ventricles (P less than 0.01). In addition, a narrowing of the subarachnoid spaces was subjectively noted during a blind reading of the early scans. Although no single scan was overtly indicative of cerebral edema, the data suggest that subclinical brain swelling may be a common occurrence during treatment of diabetic ketoacidosis in children. Sequential CT scans of the brain may provide a means of evaluating modifications of standard therapy aimed at preventing cerebral edema.