Importance Cannabis and cannabinoid drugs are widely used to treat disease or alleviate symptoms, but their efficacy for specific indications is not clear. Objective To conduct a systematic review of the benefits and adverse events (AEs) of cannabinoids. Data Sources Twenty-eight databases from inception to April 2015. Study Selection Randomized clinical trials of cannabinoids for the following indications: nausea and vomiting due to chemotherapy, appetite stimulation in HIV/AIDS, chronic pain, spasticity due to multiple sclerosis or paraplegia, depression, anxiety disorder, sleep disorder, psychosis, glaucoma, or Tourette syndrome. Data Extraction and Synthesis Study quality was assessed using the Cochrane risk of bias tool. All review stages were conducted independently by 2 reviewers. Where possible, data were pooled using random-effects meta-analysis. Main Outcomes and Measures Patient-relevant/disease-specific outcomes, activities of daily living, quality of life, global impression of change, and AEs. Results A total of 79 trials (6462 participants) were included; 4 were judged at low risk of bias. Most trials showed improvement in symptoms associated with cannabinoids but these associations did not reach statistical significance in all trials. Compared with placebo, cannabinoids were associated with a greater average number of patients showing a complete nausea and vomiting response (47% vs 20%; odds ratio [OR], 3.82 [95% CI, 1.55-9.42]; 3 trials), reduction in pain (37% vs 31%; OR, 1.41 [95% CI, 0.99-2.00]; 8 trials), a greater average reduction in numerical rating scale pain assessment (on a 0-10-point scale; weighted mean difference [WMD], −0.46 [95% CI, −0.80 to −0.11]; 6 trials), and average reduction in the Ashworth spasticity scale (WMD, −0.12 [95% CI, −0.24 to 0.01]; 5 trials). There was an increased risk of short-term AEs with cannabinoids, including serious AEs. Common AEs included dizziness, dry mouth, nausea, fatigue, somnolence, euphoria, vomiting, disorientation, drowsiness, confusion, loss of balance, and hallucination. Conclusions and Relevance There was moderate-quality evidence to support the use of cannabinoids for the treatment of chronic pain and spasticity. There was low-quality evidence suggesting that cannabinoids were associated with improvements in nausea and vomiting due to chemotherapy, weight gain in HIV infection, sleep disorders, and Tourette syndrome. Cannabinoids were associated with an increased risk of short-term AEs.

/pdf/cannabinoids-for-medical-use-a-systematic-review-and-meta-2sf620jl57.pdf

Cannabinoids for Medical Use: A Systematic Review and Meta-analysis.

Background and objectives:  This second European Federation of Neurological Societies Task Force aimed at updating the existing evidence about the pharmacological treatment of neuropathic pain since 2005.

Methods:  Studies were identified using the Cochrane Database and Medline. Trials were classified according to the aetiological condition. All class I and II randomized controlled trials (RCTs) were assessed; lower class studies were considered only in conditions that had no top-level studies. Treatments administered using repeated or single administrations were considered, provided they are feasible in an outpatient setting.

Results:  Most large RCTs included patients with diabetic polyneuropathies and post-herpetic neuralgia, while an increasing number of smaller studies explored other conditions. Drugs generally have similar efficacy in various conditions, except in trigeminal neuralgia, chronic radiculopathy and HIV neuropathy, with level A evidence in support of tricyclic antidepressants (TCA), pregabalin, gabapentin, tramadol and opioids (in various conditions), duloxetine, venlafaxine, topical lidocaine and capsaicin patches (in restricted conditions). Combination therapy appears useful for TCA-gabapentin and gabapentin-opioids (level A).

Conclusions:  There are still too few large-scale comparative studies. For future trials, we recommend to assess comorbidities, quality of life, symptoms and signs with standardized tools and attempt to better define responder profiles to specific drug treatments.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1468-1331.2010.02999.x

EFNS guidelines on the pharmacological treatment of neuropathic pain: 2010 revision

Background and objectives: This second European Federation of Neurological Societies Task Force aimed at updating the existing evidence about the pharmacological treatment of neuropathic pain since 2005. Methods: Studies were identified using the Cochrane Database and Medline. Trials were classified according to the aetiological condition. All class I and II randomized controlled trials (RCTs) were assessed; lower class studies were considered only in conditions that had no top-level studies. Treatments administered using repeated or single administrations were considered, provided they are feasible in an outpatient setting. Results: Most large RCTs included patients with diabetic polyneuropathies and postherpetic neuralgia, while an increasing number of smaller studies explored other conditions. Drugs generally have similar e!cacy in various conditions, except in trigeminal neuralgia, chronic radiculopathy and HIV neuropathy, with level A evidence in support of tricyclic antidepressants (TCA), pregabalin, gabapentin, tramadol and opioids (in various conditions), duloxetine, venlafaxine, topical lidocaine and capsaicin patches (in restricted conditions). Combination therapy appears useful for TCAgabapentin and gabapentin-opioids (level A). Conclusions: There are still too few large-scale comparative studies. For future trials, we recommend to assess comorbidities, quality of life, symptoms and signs with standardized tools and attempt to better define responder profiles to specific drug treatments.

EFNS guidelines on the pharmacological treatment of neuropathic pain: 2009 revision

Randomized, double-blind, placebo-controlled trials on neuropathic pain treatment are accumulating, so an updated review of the available evidence is needed. Studies were identified using MEDLINE and EMBASE searches. Numbers needed to treat (NNT) and numbers needed to harm (NNH) values were used to compare the efficacy and safety of different treatments for a number of neuropathic pain conditions. One hundred and seventy-four studies were included, representing a 66% increase in published randomized, placebo-controlled trials in the last 5 years. Painful poly-neuropathy (most often due to diabetes) was examined in 69 studies, postherpetic neuralgia in 23, while peripheral nerve injury, central pain, HIV neuropathy, and trigeminal neuralgia were less often studied. Tricyclic antidepressants, serotonin noradrenaline reuptake inhibitors, the anticonvulsants gabapentin and pregabalin, and opioids are the drug classes for which there is the best evidence for a clinical relevant effect. Despite a 66% increase in published trials only a limited improvement of neuropathic pain treatment has been obtained. A large proportion of neuropathic pain patients are left with insufficient pain relief. This fact calls for other treatment options to target chronic neuropathic pain. Large-scale drug trials that aim to identify possible subgroups of patients who are likely to respond to specific drugs are needed to test the hypothesis that a mechanism-based classification may help improve treatment of the individual patients.

The evidence for pharmacological treatment of neuropathic pain

The potent analgesic effects of cannabis-like drugs and the presence of CB1-type cannabinoid receptors in pain-processing areas of the brain and spinal cord, indicate that endogenous cannabinoids such as anandamide may contribute to the control of pain transmission within the central nervous system (CNS). Here we show that anandamide attenuates the pain behaviour produced by chemical damage to cutaneous tissue by interacting with CB1-like cannabinoid receptors located outside the CNS. Palmitylethanolamide (PEA), which is released together with anandamide from a common phospholipid precursor, exerts a similar effect by activating peripheral CB2-like receptors. When administered together, the two compounds act synergistically, reducing pain responses 100-fold more potently than does each compound alone. Gas-chromatography/mass-spectrometry measurements indicate that the levels of anandamide and PEA in the skin are enough to cause a tonic activation of local cannabinoid receptors. In agreement with this possibility, the CB1 antagonist SR141716A and the CB2 antagonist SR144528 prolong and enhance the pain behaviour produced by tissue damage. These results indicate that peripheral CB1-like and CB2-like receptors participate in the intrinsic control of pain initiation and that locally generated anandamide and PEA may mediate this effect.

Control of pain initiation by endogenous cannabinoids

http://www.letfreedomgrow.com/cmu/Ellis_2008.pdf

Smoked medicinal cannabis for neuropathic pain in HIV: a randomized, crossover clinical trial.

OBJECTIVE To determine the effects of low-dose oral lithium on the neuropsychological performance of individuals diagnosed with HIV-associated neurocognitive impairment. DESIGN AND METHODS The project was a single-arm, open-label, 12-week pilot study at a university-based tertiary care center. The participants were adults who had been diagnosed with HIV-associated neurocognitive impairment and had been on stable antiretroviral therapy for at least 12 weeks. Conditions that could affect cognition, worsen adherence to study procedures, or increase the risk of lithium adverse reactions were excluded. Twenty-one individuals were screened and eight were enrolled, all of whom completed the study. Oral lithium was initiated at 300 mg daily and was titrated to maintain 12-h trough concentrations between 0.4 and 0.8 mEq/l. Global neuropsychological performance was assessed by the global deficit score. RESULTS At baseline, all participants had impaired neuropsychological performance and most had reduced CD4 cell counts (median 292 cells/microl), and HIV RNA levels in plasma below 400 copies/mL (seven of eight). Titrated lithium doses ranged between 600 and 1200 mg/day. Performance improved in all eight individuals after 12 weeks, and became unimpaired in six. The study treatment was well tolerated with no grade 3 or 4 adverse events and no premature discontinuations. CONCLUSIONS Lithium resulted in improved neuropsychological performance in antiretroviral-treated, impaired individuals in this small, open-label study. Based on published in vitro data, lithium may exert this effect by inhibiting neuronal glycogen synthase kinase-3beta.

Lithium improves HIV-associated neurocognitive impairment.

We observed that antiretroviral therapy with efavirenz (EFV) produces urine samples that screen positive for Δ9-tetrahydrocannabinol (THC) exposure, despite the absence of 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid (THC metabolite). These observations were made when we were using immunoassay-based reagents to screen for drugs of abuse in patients enrolled in a study on the effects of inhaled marijuana on HIV-related neuropathy. Extensive anecdotal literature exists regarding the interference of EFV with antibody-based assays for THC metabolites in urine. In product literature, the manufacturer of EFV (Sustiva®; BMS Virology) states that EFV may interfere with THC metabolite immunoassays (1). An earlier letter to Clinical Chemistry discusses the interference of EFV with an ELISA for estradiol(2). We therefore characterized the occurrence of EFV cross-reactivity with several commercial reagents used to screen for THC exposure.

We hypothesized that cross-reactivity with THC immunoassays was the result of the interaction of EFV metabolite (and not a parent drug) with the antibody complexes used in …

Geoffrey van den Brande

Papers

Smoked medicinal cannabis for neuropathic pain in HIV: a randomized, crossover clinical trial.

Lithium improves HIV-associated neurocognitive impairment.

Characterization of Interference with 6 Commercial Δ9-Tetrahydrocannabinol Immunoassays by Efavirenz (Glucuronide) in Urine