BACKGROUND: There is a lack of consensus on the role of selective cannabinoids for the treatment of neuropathic pain (NP). Guidelines from national and international pain societies have provided contradictory recommendations. The primary objective of this systematic review and meta-analysis (SR-MA) was to determine the analgesic efficacy and safety of selective cannabinoids compared to conventional management or placebo for chronic NP.
METHODS: We reviewed randomized controlled trials that compared selective cannabinoids (dronabinol, nabilone, nabiximols) with conventional treatments (eg, pharmacotherapy, physical therapy, or a combination of these) or placebo in patients with chronic NP because patients with NP may be on any of these therapies or none if all standard treatments have failed to provide analgesia and or if these treatments have been associated with adverse effects. MEDLINE, EMBASE, and other major databases up to March 11, 2016, were searched. Data on scores of numerical rating scale for NP and its subtypes, central and peripheral, were meta-analyzed. The certainty of evidence was classified using the Grade of Recommendations Assessment, Development, and Evaluation approach.
RESULTS: Eleven randomized controlled trials including 1219 patients (614 in selective cannabinoid and 605 in comparator groups) were included in this SR-MA. There was variability in the studies in quality of reporting, etiology of NP, type and dose of selective cannabinoids. Patients who received selective cannabinoids reported a significant, but clinically small, reduction in mean numerical rating scale pain scores (0-10 scale) compared with comparator groups (-0.65 points; 95% confidence interval, -1.06 to -0.23 points; P = .002, I = 60%; Grade of Recommendations Assessment, Development, and Evaluation: weak recommendation and moderate-quality evidence). Use of selective cannabinoids was also associated with improvements in quality of life and sleep with no major adverse effects.
CONCLUSIONS: Selective cannabinoids provide a small analgesic benefit in patients with chronic NP. There was a high degree of heterogeneity among publications included in this SR-MA. Well-designed, large, randomized studies are required to better evaluate specific dosage, duration of intervention, and the effect of this intervention on physical and psychologic function.
Chronic pain occurs in as many as 85% of individuals with HIV and is associated with substantial functional impairment. Little guidance is available for HIV providers seeking to address their patients' chronic pain. We conducted a systematic review to identify clinical trials and observational studies that examined the impact of pharmacologic or non-pharmacologic interventions on pain and/or functional outcomes among HIV-infected individuals with chronic pain in high-development countries. Eleven studies met inclusion criteria and were mostly low or very low quality. Seven examined pharmacologic interventions (gabapentin, pregabalin, capsaicin, analgesics including opioids) and four examined non-pharmacologic interventions (cognitive behavioral therapy, self-hypnosis, smoked cannabis). The only controlled studies with positive results were of capsaicin and cannabis, and had short-term follow-up (≤12 weeks). Among the seven studies of pharmacologic interventions, five had substantial pharmaceutical industry sponsorship. These findings highlight several important gaps in the HIV/chronic pain literature that require further research.
BACKGROUND: Recently published systematic reviews came to different conclusions with respect to the efficacy, tolerability and safety of cannabinoids for treatment of chronic neuropathic pain.
MATERIAL AND METHODS: A systematic search of the literature was carried out in MEDLINE, the Cochrane central register of controlled trials (CENTRAL) and clinicaltrials.gov up until November 2015. We included double-blind randomized placebo-controlled studies (RCT) of at least 2 weeks duration and with at least 9 patients per treatment arm comparing medicinal cannabis, plant-based or synthetic cannabinoids with placebo or any other active drug treatment in patients with chronic neuropathic pain. Clinical endpoints of the analyses were efficacy (more than 30 % or 50 % reduction of pain, average pain intensity, global improvement and health-related quality of life), tolerability (drop-out rate due to side effects, central nervous system and psychiatric side effects) and safety (severe side effects). Using a random effects model absolute risk differences (RD) were calculated for categorical data and standardized mean differences (SMD) for continuous variables. The methodological quality of RCTs was rated by the Cochrane risk of bias tool.
RESULTS: We included 15 RCTs with 1619 participants. Study duration ranged between 2 and 15 weeks. Of the studies 10 used a plant-derived oromucosal spray with tetrahydrocannabinol/cannabidiol, 3 studies used a synthetic cannabinoid (2 with nabilone and 1 with dronabinol) and 2 studies used medicinal cannabis. The 13 studies with parallel or cross-over design yielded the following results with 95 % confidence intervals (CI): cannabinoids were superior to placebo in the reduction of mean pain intensity with SMD - 0.10 (95 % CI - 0.20- - 0.00, p = 0.05, 13 studies with 1565 participants), in the frequency of at least a 30 % reduction in pain with an RD of 0.10 [95 % CI 0.03-0.16, p = 0.004, 9 studies with 1346 participants, number needed to treat for additional benefit (NNTB) 14, 95 % CI 8-45] and in the frequency of a large or very large global improvement with an RD of 0.09 (95 % CI 0.01-0.17, p = 0.009, 7 studies with 1092 participants). There were no statistically significant differences between cannabinoids and placebo in the frequency of at least a 50 % reduction in pain, in improvement of health-related quality of life and in the frequency of serious adverse events. Patients treated with cannabinoids dropped out more frequently due to adverse events with an RD of 0.04 [95 % CI 0.01-0.07, p = 0.009, 11 studies with 1572 participants, number needed to treat for additional harm (NNTH) 19, 95 % CI 13-37], reported central nervous system side effects more frequently with an RD of 0.38 (95 % CI 0.18-0.58, p = 0.0003, 9 studies with 1304 participants, NNTH 3, 95 % CI 2-4) and psychiatric side effects with an RD of 0.11 (95 % CI 0.06-0.16, p < 0.0001, 9 studies with 1304 participants, NNTH 8, 95 % CI 7-12).
CONCLUSION: Cannabinoids were marginally superior to placebo in terms of efficacy and inferior in terms of tolerability. Cannabinoids and placebo did not differ in terms of safety during the study period. Short-term and intermediate-term therapy with cannabinoids can be considered in selected patients with chronic neuropathic pain after failure of first-line and second-line therapies.
Nabilone, a synthetic cannabinoid, is approved in many countries including, but not limited to, Canada, the United States, Mexico, and the United Kingdom for the treatment of severe nausea and vomiting associated with chemotherapy. Clinical evidence is emerging for its use in managing pain conditions with different etiologies. We review the efficacy and safety of nabilone for various types of pain as well as its abuse potential, precautions and contraindications, and drug interactions; summarize pertinent clinical practice guidelines; and provide recommendations for dosing, monitoring, and patient education. Citations involving nabilone were identified through systematic reviews evaluating cannabinoids for pain. A systematic search (updated July 23, 2015) of the Ovid MEDLINE, EMBASE, PubMed, and Cochrane Library databases was performed. Eight randomized controlled trials, two prospective cohort trials, and one retrospective chart review were retrieved. Cancer pain, chronic noncancer pain, neuropathic pain, fibromyalgia, and pain associated with spasticity were the pain conditions evaluated. Nabilone was most commonly used as adjunctive therapy and led to small but significant reductions in pain. The most common adverse drug reactions included euphoria, drowsiness, and dizziness. Nabilone was rarely associated with severe adverse drug reactions requiring drug discontinuation, and the likelihood of abuse was thought to be low. Although the optimal role of nabilone in the management of pain is yet to be determined, certain clinical practice guidelines consider nabilone as a third-line agent.
In 2010 a review by Hazekamp and Grotenhermen covered controlled clinical trials of the years 2006-2009 on cannabis-based medicines, which followed the example of the review by Ben Amar (2006). The current review reports on the more recent clinical data available from 2010-2014. A systematic search was performed in the scientific database of PubMed, focused on clinical studies that were randomized, (double) blinded, and placebo-controlled. The key words used were: cannabis, marijuana, marihuana, hashish, cannabinoid(s), tetrahydrocannabinol, THC, CBD, dronabinol, Marinol, nabilone, Cannador, nabiximols and Sativex. For the final selection, only properly controlled clinical trials were retained. Open-label studies were excluded, except if they were a direct continuation of a study discussed here. Thirty-two controlled studies evaluating the therapeutic effects of cannabinoids were identified. For each clinical trial, the country where the project was held, the number of patients assessed, the type of study and comparisons done, the products and the dosages used, their efficacy and their adverse effects are described. Based on the clinical results, cannabinoids present an interesting therapeutic potential mainly as analgesics in chronic neuropathic pain and spasticity in multiple sclerosis. But a range of other indications also seem promising. CBD (cannabidiol) emerges as another valuable cannabinoid for therapeutic purposes besides THC.
BACKGROUND: In the absence of an ideal treatment for chronic pain associated with rheumatic diseases, there is interest in the potential effects of cannabinoid molecules, particularly in the context of global interest in the legalization of herbal cannabis for medicinal use.
METHODS: A systematic search until April 2015 was conducted in Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, www.cannabis-med.org and clinicaltrials.gov for randomized controlled trials with a study duration of at least 2 weeks and at least ten patients per treatment arm with herbal cannabis or pharmaceutical cannabinoid products in fibromyalgia syndrome (FMS), osteoarthritis (OA), chronic spinal pain, and rheumatoid arthritis (RA) pain. Outcomes were reduction of pain, sleep problems, fatigue and limitations of quality of life for efficacy, dropout rates due to adverse events for tolerability, and serious adverse events for safety. The methodology quality of the randomized controlled trials (RCTs) was evaluated by the Cochrane Risk of Bias Tool.
RESULTS: Two RCTs of 2 and 4 weeks duration respectively with nabilone, including 71 FMS patients, one 4-week trial with nabilone, including 30 spinal pain patients, and one 5-week study with tetrahydrocannbinol/cannabidiol, including 58 RA patients were included. One inclusion criterion was pain refractory to conventional treatment in three studies. No RCT with OA patients was found. The risk of bias was high for three studies. The findings of a superiority of cannabinoids over controls (placebo, amitriptyline) were not consistent. Cannabinoids were generally well tolerated despite some troublesome side effects and safe during the study duration.
CONCLUSIONS: Currently, there is insufficient evidence for recommendation for any cannabinoid preparations for symptom management in patients with chronic pain associated with rheumatic diseases.
BACKGROUND: This review is one of a series on drugs used to treat fibromyalgia. Fibromyalgia is a clinically well-defined chronic condition of unknown aetiology characterised by chronic widespread pain that often co-exists with sleep problems and fatigue affecting approximately 2% of the general population. People often report high disability levels and poor health-related quality of life (HRQoL). Drug therapy focuses on reducing key symptoms and disability, and improving HRQoL. Cannabis has been used for millennia to reduce pain and other somatic and psychological symptoms.
OBJECTIVES: To assess the efficacy, tolerability and safety of cannabinoids for fibromyalgia symptoms in adults.
SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE to April 2016, together with reference lists of retrieved papers and reviews, three clinical trial registries, and contact with trial authors.
SELECTION CRITERIA: We selected randomised controlled trials of at least four weeks' duration of any formulation of cannabis products used for the treatment of adults with fibromyalgia.
DATA COLLECTION AND ANALYSIS: Two review authors independently extracted the data of all included studies and assessed risk of bias. We resolved discrepancies by discussion. We performed analysis using three tiers of evidence. First tier evidence was derived from data meeting current best standards and subject to minimal risk of bias (outcome equivalent to substantial pain intensity reduction, intention-to-treat analysis without imputation for drop-outs; at least 200 participants in the comparison, eight to 12 weeks' duration, parallel design), second tier evidence from data that did not meet one or more of these criteria and were considered at some risk of bias but with adequate numbers (i.e. data from at least 200 participants) in the comparison, and third tier evidence from data involving small numbers of participants that were considered very likely to be biased or used outcomes of limited clinical utility, or both. We assessed the evidence using GRADE (Grading of Recommendations Assessment, Development and Evaluation).
MAIN RESULTS: We included two studies with 72 participants. Overall, the two studies were at moderate risk of bias. The evidence was derived from group mean data and completer analysis (very low quality evidence overall). We rated the quality of all outcomes according to GRADE as very low due to indirectness, imprecision and potential reporting bias.The primary outcomes in our review were participant-reported pain relief of 50% or greater, Patient Global Impression of Change (PGIC) much or very much improved, withdrawal due to adverse events (tolerability) and serious adverse events (safety). Nabilone was compared to placebo and to amitriptyline in one study each. Study sizes were 32 and 40 participants. One study used a cross-over design and one used a parallel group design; study duration was four or six weeks. Both studies used nabilone, a synthetic cannabinoid, with a bedtime dosage of 1 mg/day. No study reported the proportion of participants experiencing at least 30% or 50% pain relief or who were very much improved. No study provided first or second tier (high to moderate quality) evidence for an outcome of efficacy, tolerability and safety. Third tier (very low quality) evidence indicated greater reduction of pain and limitations of HRQoL compared to placebo in one study. There were no significant differences to placebo noted for fatigue and depression (very low quality evidence). Third tier evidence indicated better effects of nabilone on sleep than amitriptyline (very low quality evidence). There were no significant differences between the two drugs noted for pain, mood and HRQoL (very low quality evidence). More participants dropped out due to adverse events in the nabilone groups (4/52 participants) than in the control groups (1/20 in placebo and 0/32 in amitriptyline group). The most frequent adverse events were dizziness, nausea, dry mouth and drowsiness (six participants with nabilone). Neither study reported serious adverse events during the period of both studies. We planned to create a GRADE 'Summary of findings' table, but due to the scarcity of data we were unable to do this. We found no relevant study with herbal cannabis, plant-based cannabinoids or synthetic cannabinoids other than nabilone in fibromyalgia.
AUTHORS' CONCLUSIONS: We found no convincing, unbiased, high quality evidence suggesting that nabilone is of value in treating people with fibromyalgia. The tolerability of nabilone was low in people with fibromyalgia.
OBJECTIVE: To assess the efficacy, tolerability, and safety of cannabinoids (phyto- and syntheto-) in the management of rheumatic diseases.
METHODS: Multiple databases, including Medline, Embase, and CENTRAL, were searched. Randomized controlled trials with outcomes of pain, sleep, quality of life, tolerability (dropouts due to adverse events), and safety (serious adverse events), with comparison of cannabinoids with any type of control, were included. Study methodology quality was evaluated with the Cochrane risk of bias tool.
RESULTS: In 4 short-term studies comprising 203 patients (58 with rheumatoid arthritis, 71 with fibromyalgia, and 74 with osteoarthritis [OA]), cannabinoids had a statistically significant effect on pain in 2, sleep in 2, and improved quality of life in 1, with the OA study prematurely terminated due to futility. The risk of bias was high for all 3 completed studies. Dizziness, cognitive problems, and drowsiness, as well as nausea, were reported for almost half of the patients. No serious adverse events were reported for cannabinoids during the study duration. No studies of herbal cannabis were identified.
CONCLUSION: Extremely small sample sizes, short study duration, heterogeneity of rheumatic conditions and products, and absence of studies of herbal cannabis allow for only limited conclusions for the effects of cannabinoids in rheumatic conditions. Pain relief and effect on sleep may have some potential therapeutic benefit, but with considerable mild to moderate adverse events. There is currently insufficient evidence to recommend cannabinoid treatments for management of rheumatic diseases pending further study.
UNLABELLED: Chronic neuropathic pain, the most frequent condition affecting the peripheral nervous system, remains underdiagnosed and difficult to treat. Inhaled cannabis may alleviate chronic neuropathic pain. Our objective was to synthesize the evidence on the use of inhaled cannabis for chronic neuropathic pain. We performed a systematic review and a meta-analysis of individual patient data. We registered our protocol with PROSPERO CRD42011001182. We searched in Cochrane Central, PubMed, EMBASE, and AMED. We considered all randomized controlled trials investigating chronic painful neuropathy and comparing inhaled cannabis with placebo. We pooled treatment effects following a hierarchical random-effects Bayesian responder model for the population-averaged subject-specific effect. Our evidence synthesis of individual patient data from 178 participants with 405 observed responses in 5 randomized controlled trials following patients for days to weeks provides evidence that inhaled cannabis results in short-term reductions in chronic neuropathic pain for 1 in every 5 to 6 patients treated (number needed to treat = 5.6 with a Bayesian 95% credible interval ranging between 3.4 and 14). Our inferences were insensitive to model assumptions, priors, and parameter choices. We caution that the small number of studies and participants, the short follow-up, shortcomings in allocation concealment, and considerable attrition limit the conclusions that can be drawn from the review. The Bayes factor is 332, corresponding to a posterior probability of effect of 99.7%.
PERSPECTIVE: This novel Bayesian meta-analysis of individual patient data from 5 randomized trials suggests that inhaled cannabis may provide short-term relief for 1 in 5 to 6 patients with neuropathic pain. Pragmatic trials are needed to evaluate the long-term benefits and risks of this treatment.
An updated systematic review of randomized controlled trials examining cannabinoids in the treatment of chronic non-cancer pain was conducted according to PRISMA guidelines for systematic reviews reporting on health care outcomes. Eleven trials published since our last review met inclusion criteria. The quality of the trials was excellent. Seven of the trials demonstrated a significant analgesic effect. Several trials also demonstrated improvement in secondary outcomes (e.g., sleep, muscle stiffness and spasticity). Adverse effects most frequently reported such as fatigue and dizziness were mild to moderate in severity and generally well tolerated. This review adds further support that currently available cannabinoids are safe, modestly effective analgesics that provide a reasonable therapeutic option in the management of chronic non-cancer pain.
There is a lack of consensus on the role of selective cannabinoids for the treatment of neuropathic pain (NP). Guidelines from national and international pain societies have provided contradictory recommendations. The primary objective of this systematic review and meta-analysis (SR-MA) was to determine the analgesic efficacy and safety of selective cannabinoids compared to conventional management or placebo for chronic NP.
METHODS:
We reviewed randomized controlled trials that compared selective cannabinoids (dronabinol, nabilone, nabiximols) with conventional treatments (eg, pharmacotherapy, physical therapy, or a combination of these) or placebo in patients with chronic NP because patients with NP may be on any of these therapies or none if all standard treatments have failed to provide analgesia and or if these treatments have been associated with adverse effects. MEDLINE, EMBASE, and other major databases up to March 11, 2016, were searched. Data on scores of numerical rating scale for NP and its subtypes, central and peripheral, were meta-analyzed. The certainty of evidence was classified using the Grade of Recommendations Assessment, Development, and Evaluation approach.
RESULTS:
Eleven randomized controlled trials including 1219 patients (614 in selective cannabinoid and 605 in comparator groups) were included in this SR-MA. There was variability in the studies in quality of reporting, etiology of NP, type and dose of selective cannabinoids. Patients who received selective cannabinoids reported a significant, but clinically small, reduction in mean numerical rating scale pain scores (0-10 scale) compared with comparator groups (-0.65 points; 95% confidence interval, -1.06 to -0.23 points; P = .002, I = 60%; Grade of Recommendations Assessment, Development, and Evaluation: weak recommendation and moderate-quality evidence). Use of selective cannabinoids was also associated with improvements in quality of life and sleep with no major adverse effects.
CONCLUSIONS:
Selective cannabinoids provide a small analgesic benefit in patients with chronic NP. There was a high degree of heterogeneity among publications included in this SR-MA. Well-designed, large, randomized studies are required to better evaluate specific dosage, duration of intervention, and the effect of this intervention on physical and psychologic function.
