Studying the efficacy of tetrahydrocannabinol (THC) and cannabidiol (CBD) combinations, as well as the efficacy of other phytocannabinoids, in reducing chronic neuropathic pain caused by trauma or disease.
Chronic neuropathic pain is an abnormal pain syndrome caused by damage to peripheral nerves, spinal cord, or brain by physical trauma (eg accidents, surgery, stroke), or by disease (eg diabetes, cancer, immune disorders). The specific problems with current drugs is they have moderate and variable effectiveness, and they produce a range of problematic side effects.
While there have been a number of small scale clinical trials of cannabis and some of its basic extracts in chronic pain sufferers, there is little preclinical experimental evidence to support the specific combinations of cannabis constituents currently undergoing clinical investigation. In these studies the most commonly studied constituents are tetrahydrocannabinol (THC), the major psychoactive ingredient of cannabis, and the non-psychoactive ingredient cannabidiol (CBD).
We believe that the dosing regimens for the co-administration of phytocannabinoids, in conditions such as neuropathic pain, need to be properly evaluated in a well-established preclinical model of neuropathic pain. We are currently studying the efficacy of tetrahydrocannabinol and cannabidiol combinations, as well as the efficacy of other phytocannabinoids, in reducing neuropathic pain.
Commenced – Feb 2016. The project is ongoing.
Drug discovery and preclinical disease models.
The Lambert Initiative.
We found that THC and CBD reduced neuropathic pain. CBD had no adverse side effects. The 1:1 combination of THC and CBD synergistically reduced neuropathic pain with 100-fold greater efficacy than predicted from an additive interaction. THC also synergistically enhanced the efficacy of current first-line neuropathic pain treatments gabapentin and duloxetine.
We have presented our results at the following meetings: