Pharmacological management of chronic neuropathic pain - consensus statement and guidelines from the Canadian Pain Society.

Neuropathic pain (NeP), generated by disorders of the peripheral and central nervous system, can be particularly severe and disabling. Prevalence estimates indicate that 2% to 3% of the population in the developed world suffer from NeP, which suggests that up to one million Canadians have this disabling condition. Evidence-based guidelines for the pharmacological management of NeP are therefore urgently needed. Randomized, controlled trials, systematic reviews and existing guidelines focusing on the pharmacological management of NeP were evaluated at a consensus meeting. Medications are recommended in the guidelines if their analgesic efficacy was supported by at least one methodologically sound, randomized, controlled trial showing significant benefit relative to placebo or another relevant control group. Recommendations for treatment are based on degree of evidence of analgesic efficacy, safety, ease of use and cost-effectiveness. Analgesic agents recommended for first-line treatments are certain antidepressants (tricyclics) and anticonvulsants (gabapentin and pregabalin). Second-line treatments recommended are serotonin noradrenaline reuptake inhibitors and topical lidocaine. Tramadol and controlled-release opioid analgesics are recommended as third-line treatments for moderate to severe pain. Recommended fourth-line treatments include cannabinoids, methadone and anticonvulsants with lesser evidence of efficacy, such as lamotrigine, topiramate and valproic acid. Treatment must be individualized for each patient based on efficacy, side-effect profile and drug accessibility, including cost. Further studies are required to examine head-to-head comparisons among analgesics, combinations of analgesics, long-term outcomes, and treatment of pediatric and central NeP.

Pain expectations in neuropathic pain: Is it best to be optimistic?

BACKGROUND: Pain expectancy may be an important variable that has been found to influence the effectiveness of treatments for pain. Much of the literature supports a self-fulfilment perspective where expectations for pain relief predict the actual pain experienced. However, in conditions such as neuropathic pain (NeP) where pain relief is difficult to attain, expectations for pain relief could be unrealistic. The objective of this study was to investigate the relationship between realistic/unrealistic expectations and 6-month, post-treatment outcomes. METHODS: We performed a retrospective analysis of a large cohort of patients with NeP (n = 789) attending tertiary care centres to determine the association between unrealistic (both positive and negative) and realistic expectations with outcomes after multidisciplinary treatment. An expectation variable with three categories was calculated: realistic expectations were those whose expected reduction in pain was similar to the observed mean group reduction in pain, while optimistic and pessimistic expectations were those who over- or under-estimated the expected response to treatment, respectively. The association between baseline realistic/unrealistic expectations and 6-month pain-related disability, catastrophizing and psychological distress was assessed. RESULTS: Univariable analyses suggested that realistic expectations were associated with lower levels of disability, catastrophizing and psychological distress, compared to unrealistic expectations. However, after adjustment for baseline symptom severity, multivariable analysis revealed that patients with optimistic expectations had lower levels of disability, than those with realistic expectations. Those with pessimistic expectations had higher levels of catastrophizing and psychological distress at follow-up. CONCLUSIONS: These findings are largely congruent with the self-fulfilment perspective to expectations. SIGNIFICANCE: This study defined realistic pain expectations with patient data. Examining the relationship between expectations between pain and disability in a large cohort of patients with neuropathic pain.

Development and Implementation of a Registry of Patients Attending Multidisciplinary Pain Treatment Clinics: The Quebec Pain Registry.

The Quebec Pain Registry (QPR) is a large research database of patients suffering from various chronic pain (CP) syndromes who were referred to one of five tertiary care centres in the province of Quebec (Canada). Patients were monitored using common demographics, identical clinical descriptors, and uniform validated outcomes. This paper describes the development, implementation, and research potential of the QPR. Between 2008 and 2013, 6902 patients were enrolled in the QPR, and data were collected prior to their first visit at the pain clinic and six months later. More than 90% of them (mean age ± SD: 52.76 ± 4.60, females: 59.1%) consented that their QPR data be used for research purposes. The results suggest that, compared to patients with serious chronic medical disorders, CP patients referred to tertiary care clinics are more severely impaired in multiple domains including emotional and physical functioning. The QPR is also a powerful and comprehensive tool for conducting research in a "real-world" context with 27 observational studies and satellite research projects which have been completed or are underway. It contains data on the clinical evolution of thousands of patients and provides the opportunity of answering important research questions on various aspects of CP (or specific pain syndromes) and its management.

Medical education on cannabis and cannabinoids: Perspectives, challenges, and opportunities.

The global regulatory landscape regarding the medical use of cannabis and cannabinoids is changing rapidly. This has considerable impact on health care professionals who currently receive little or no education on issues regarding medical cannabis. We propose a 'cannabis curriculum' that covers the spectrum of historical, botanical, physiological, clinical and legal issues to allow health care professionals to engage in meaningful discussions with their patients and colleagues around this stigmatized and controversial subject.

Impact on health-related quality of life and costs of managing chronic neuropathic pain in academic pain centres: Results from a one-year prospective observational Canadian study.

BACKGROUND: The management of chronic pain, including neuropathic pain (NeP), is a major public health issue. However, there is a paucity of data evaluating pain management strategies in real-life settings. OBJECTIVE: To inform policy makers about the economic value of managing chronic NeP in academic centres by conducting a subeconomic assessment of a Canadian multicentre cohort study aimed at determining the long-term outcomes of the management of chronic NeP in academic pain centres. Specific questions regarding the economic value of this type of program were answered by a subset of patients to provide further information to policy makers. METHODS: Baseline demographic information and several pain-related measurements were collected at baseline, three, six and 12 months in the main study. A resource use questionnaire aimed at determining NeP-related costs and the EuroQoL-5 Dimension were collected in the subset study from consenting patients. Statistical analyses were conducted to compare outcomes over time and according to responder status. RESULTS: A total of 298 patients were evaluated in the present economic evaluation. The mean (± SD) age of the participants was 53.7±14.0 years, and 56% were female. At intake, the mean duration of NeP was >5 years. Statistically significant improvements in all pain and health-related quality of life outcomes were observed between the baseline and one-year visits. Use decreased over time for many health care resources (eg, visits to the emergency room decreased by one-half), which resulted in overall cost savings. CONCLUSION: The results suggest that increased access to academic pain centres should be facilitated in Canada.

Clearing the smoke around medical marijuana.

The hazy world of "medical marijuana" continues to cry out for clear data on which to base medical decision making and rational policy design. In this issue of Clinical Pharmacology & Therapeutics, Abrams and colleagues report that vaporized cannabis does not meaningfully affect opioid plasma levels and may even augment the efficacy of oxycodone and morphine in patients with chronic non-cancer pain. This Commentary considers the implications of this work for clinical practice and further research initiatives.

The medicinal use of cannabis in the UK: results of a nationwide survey.

The use of cannabis for medical purposes is a controversial but an important topic of public and scientific interest. We report on the results of a self-administered questionnaire study conducted in the United Kingdom between 1998 and 2002. The questionnaire consisted of 34 items and included demographic data, disease and medication use patterns and cannabis use profiles. Subjects were self-selected; 3663 questionnaires were distributed and 2969 were returned [1805 (60.9%) women, mean age 52.7 years (SD 12.7)]. Medicinal cannabis use was reported by patients with chronic pain (25%), multiple sclerosis and depression (22% each), arthritis (21%) and neuropathy (19%). Medicinal cannabis use was associated with younger age, male gender and previous recreational use (p < 0.001). While caution must be exercised in interpreting these data, they point to the need for clinical studies of cannabis and cannabinoids with standardised and quality-controlled products.

Patterns of cannabis use among patients with multiple sclerosis.

To estimate the patterns and prevalence of cannabis use among patients with multiple sclerosis (MS), 220 patients were surveyed in Halifax, Nova Scotia. Seventy-two subjects (36%) reported ever having used cannabis for any purpose; 29 respondents (14%) reported continuing use of cannabis for symptom treatment. Medical cannabis use was associated with male gender, tobacco use, and recreational cannabis use. The symptoms reported by medical cannabis users to be most effectively relieved were stress, sleep, mood, stiffness/spasm, and pain.

Day-care management of sickle cell painful crisis in Jamaica: a model applicable elsewhere?

In the U.K. and the U.S.A., painful crises account for 80-90% of sickle-related hospital admissions, with average durations of 5-11 d. In Jamaica, many severe painful crises are managed in a day-care centre. Patients (n=1160) with homozygous sickle cell (SS) disease aged 18 years and over were registered with the clinic during a 1-year study period. Of these, 216 patients with 476 painful crises attended the day-care facility for a total of 686 d. Most patients (119 or 55.1%) had single crises and for most crises (338 or 71%), patients attended for only 1 d, when they were given bed rest, assurance, rehydration and analgesia. Patients with complicated painful crises were usually referred for admission after initial pain relief and the rest were monitored during the day. In the evening they were given the option of hospital admission or allowed home with oral analgesia. Hospital admission for complicated painful crises or inadequate pain relief occurred in 42 (8.8%) crises and home management in 434 (91.2%) crises. Of 186 patients initially selecting home management, 20% returned for further day-care and five (2.7%) died during subsequent admission for that painful crisis, one without other known complications, two with acute chest syndrome (one associated with Salmonella septicaemia), another with Salmonella septicaemia, and one with dengue haemorrhagic fever. With suitable oral analgesia, adequate education and support, the majority of severe painful crises in SS disease in Jamaica have been managed on an outpatient basis. This model of patient care may merit assessment in other communities where painful crises are a common clinical problem.