HAMILTON, ON, AUGUST 29, 2019 – A growing body of evidence suggests potential for cannabinoids—non-psychoactive compounds found in the cannabis plant—to treat pain. A clinical trial, however, found no benefit from routine use. A new dose-escalation study in mice reported a 30 per cent reduction in pain responses compared with placebo. These results, published in Scientific Reports, support a trial of cannabidiol (CBD), a non-psychoactive compound, active in the body, for neuropathic pain, albeit at lower doses than those reported in previous trials.
Sonia Migra, principal investigator and director of the Pain Management Research Institute at St George’s University of London, was contacted about the results. She said: “On an average day, I have to take 20 minutes for some everyday activities that were previously uncontrollable. Chronic pain patients may find that their pain has become intrusive. Clinical studies of CBD have shown some promise for potential for the management of pain, an act of decreasing both anxiety and the likelihood of triggering dangerous non-adherence.” We saw a 30 per cent reduction in pain responses in both experimental groups, with significantly more beneficial responses in the experimental and clinical arms.”
Concentration and timing of CBD was not significantly different between the experimental and clinical arms. Both groups responded to a 15-minute n-diphyllogoxin infusion, while the control group took a placebo or no treatment. THC was detected in the cannabinoid product.
A subjective effect profile was assessed for both groups. THC concentrations were found to be 0.2-0.8 milligrams per millilitre (mg/kg) in the injection and 0.5-1 mg/kg in the placebo test. Study participants also reported an effect on desire to engage with pain in a negative way within the same day. The THC response was significantly higher in the experimental dose arm, compared with the placebo dose-escalation arm.
CBD was then administered the day after the administration of the placebo THC with the animal probing test, to see whether CBD could reduce a participant’s daily desire to engage in pain, pain intensity and fear of triggering severe adverse drug events. Results were found as normal response in both groups. The other half of the placebo-vaccinated group received CBD with the injection. Abstain from THC and placebo-controlled treatments reduced participants’ daily pain response, pain-frequency and discomfort responses; reduced pain tolerance; normalized sensory-motor responses; and improved motivation to engage in pleasurable behaviours such as drinking alcohol.
Psoriasis is one of many non-inflammatory skin diseases affecting 1-3 per cent of the human population, accounting for over 8 million reported cases in 10 countries. Like many types of inflammatory skin disorders, CBD has shown little efficacy, and is thought to play a role in suppressing appetite and reducing appetite for healthy foods and exercise as well as pain processes. It is currently made by pressing extracts of the cannabis plant, but the effect of standardized CBD still needs to be determined.
Oral CBD trials in healthy participants have shown it to be safely effective for both pain and physical disability as well as cognitive impairment. The Drug Density Score (DRS) of oral CBD in healthy adults has been just above safe and effective. Different doses tested in this trial have been found to be effective for current pain and relatively low-dose dosing of CBD, but adverse events were consistently reported, suggesting a lack of value in oral CBD trials in the treatment of chronic pain.
G.V. Kuscinski, R.N., lecturer and chair of the Department of Systems Pharmacology and Therapeutics at St George’s, said: “We still don’t understand the optimal dose or schedule of topical application of therapeutic cannabinoids for treating the patient’s pain. Clinical studies have shown that topical application of CBD in mice is nonspecific for reducing pain and is not effective in reducing the desire to engage in other forms of pain such as nausea.” He stressed “there is a need for new protocol development for human clinical trials.”