No abstract

Many people throughout the world have both chronic pain and obesity. Overweight and obese people are more prone to a proinflammatory state manifesting as metabolic syndrome but also to a higher prevalence of chronic pain comorbidities. Obesity and a high body mass index (BMI) are associated with impaired functional capacity and reduced quality of life (QoL) in patients with chronic pain conditions. Systemic inflammation is not only involved in metabolic syndrome but it also initiates and perpetuates chronic pain. Changes in lifestyle, behavior, physical activity, and diet have demonstrated benefits in functional capacity and QoL; therefore, patient assessment should tackle high BMI and metabolic syndrome as part of the treatment of chronic pain. A healthier lifestyle would lead to a lower inflammatory state and consequently to an improvement in function and QoL in overweight or obese patients who have chronic pain conditions.

The objective of this study was to assess the efficacy and safety of amitriptyline as a treatment of FM. A comprehensive computerized search in Medline (Pubmed), EMBASE and The Cochrane Library was performed. Randomized controlled trials (RCTs) comparing amitriptyline vs placebo in adult patients suffering from FM were identified, the methodological quality was assessed and the results of the main outcomes were evaluated. Ten RCTs were identified. Large clinical variability and statistical heterogeneity precluded quantitative meta-analysis. Overall, the study quality was moderate to high. Amitriptyline 25 mg/day (six RCTs) demonstrated a therapeutic response compared with placebo in the domains of pain, sleep, fatigue and overall patient and investigator impression. This benefit was generally seen at 6-8 weeks of treatment but no effect was noted at 12 weeks. Amitriptyline 50 mg/day (four RCTs) did not demonstrate a therapeutic effect compared with placebo. Neither dose of amitriptyline had an effect on tender points count. No clear statements on adverse events with amitriptyline can be made due to inconsistencies in data among the studies. A definitive clinical recommendation regarding the efficacy of amitriptyline for FM symptoms cannot be made. There is some evidence to support the short-term efficacy of amitriptyline 25 mg/day in FM. There is no evidence to support the efficacy of amitriptyline at higher doses or for periods >8 weeks. More stringent RCTs with longer follow-up periods are required to determine the long-term efficacy and safety of the amitriptyline and define its role in the multidisciplinary management of FM.

Studies suggest that around 20% of adults in Europe experience chronic pain, which not only has a considerable impact on their quality of life but also imposes a substantial economic burden on society. More than one-third of these people feel that their pain is inadequately managed. A range of analgesic drugs is currently available, but recent guidelines recommend that NSAIDs and COX-2 inhibitors should be prescribed cautiously. Although the short-term efficacy of opioids is good, adverse events are common and doses are frequently limited by tolerability problems. There is a perceived need for improved pharmacological treatment options. Currently, many treatment decisions are based solely on pain intensity. However, chronic pain is multifactorial and this apaproach ignores the fact that different causative mechanisms may be involved. The presence of more than one causative mechanism means that chronic pain can seldom be controlled by a single agent. Therefore, combining drugs with different analgesic actions increases the probability of interrupting the pain signal, but is often associated with an increased risk of drug/drug interactions, low compliance and increased side effects. Tapentadol combines μ-opioid receptor agonism and noradrenaline reuptake inhibition in a single molecule, with both mechanisms contributing to its analgesic effects. Preclinical testing has shown that μ-opioid agonism is primarily responsible for analgesia in acute pain, whereas noradrenaline reuptake inhibition is more important in chronic pain. In clinical trials in patients with chronic pain, the efficacy of tapentadol was similar to that of oxycodone, but it produced significantly fewer gastrointestinal side-effects and treatment discontinuations. Pain relief remained stable throughout a 1-year safety study. Thus, tapentadol could possibly overcome some of the limitations of currently available analgesics for the treatment of chronic pain.