By Shannon Pacella, DPT, PHRC Lexington
First things first: if you haven’t already read the Part 1 to this post, please do so first!
There are a few updates since my first post regarding laws and legislature for marijuana (cannabis) use throughout the United States.
Currently, 29 states plus Washington, D.C. have legalized the use of medicinal marijuana, while nine of these states plus D.C. have legalized recreational marijuana use. Out of the remaining 21 states, 18 of them have legalized cannabidiol (CBD) which is considered to be non-psychoactive.1 Each state has their own specific parameters regarding the amount and form of marijuana that is allowed.
Almost every state has some degree of legalized use of marijuana (medicinal or cannabidiol use), which is pleasantly surprising especially since there has continued to be a lack of research being done. I was hoping by the time I got around to writing a part two, that I’d have loads of evidence based research to tout. Although I do not have hundreds (or evens tens) of research articles to delve into, the ones I am going to discuss do a good job of strengthening the relationship between medicinal marijuana use and treating pain.
In a review article by Hill and Palastro, chronic pain and neuropathic pain were two conditions with moderate to high quality evidence supporting the efficacy of medical cannabis pharmacotherapy.2 Animal pain models were used to demonstrate that the endocannabinoid system plays an active role in controlling pain; THC was shown to produce analgesic (pain relieving) and antihyperalgesic (decreased sensitivity to pain) effects in mice.2 Anecdotally, the pain relieving effects of THC has been supported by patients with chronic pain. Another review, demonstrated by multiple positive randomized placebo-controlled trials, determined that there was ‘high quality evidence’ to support the administration of cannabis or cannabinoid pharmacotherapy for treating neuropathic pain and chronic pain.2
“A recent report released by the National Academy of Science, Engineering, and Medicine in the United States stipulated that there was ‘conclusive or substantial evidence’ that cannabis or cannabinoids are effective treatments for chronic pain.”2
To further this connection, a systematic review and meta-analysis by Whiting, et al., 28 randomized clinical trials of cannabis and cannabinoid use for chronic pain, involving 2,454 participants was assessed.3 When compared with placebo, there was a higher reduction in pain measures with cannabinoids – the average number of patients who reported a reduction in pain of at least 30% was greater with cannabinoids than with placebo.3 Most of the studies reviewed suggested that cannabinoids were associated with improvements in chronic neuropathic pain, but these associations did not reach statistical significance in all of the studies.3
The final article I looked at discusses the clinical significance of endocannabinoids in endometriosis pain management. The endocannabinoid system (ECS) may serve as a pharmacological target for endometriosis treatments for pain management.4 The ECS is defined as a group of cannabinoid receptors located in the brain, central nervous system, and peripheral nervous system.4 The ECS is basically our body’s system that processes cannabinoids. There are two types of cannabinoid receptors: cannabinoid 1 (CB1) and cannabinoid 2 (CB2) receptors.4 Both CB1 and CB2 receptors are found within different membranes of the body: CB1 receptors are found primarily in the uterus, while CB2 receptors are found in the intestines, lungs, pancreas, and skin.4 Women with endometriosis have less CB1 receptors in endometrial tissue, leading some studies to describe endometriosis as an ‘endocannabinoid deficiency’.4
Analysis of clinical studies that focused on the relationship between ECS modulation and endometriosis-associated pain came up with some promising results:
- All of the studies showed a statistically significant improvement in chronic pelvic pain and dysmenorrhea (pain during menstruation).4
- The studies that specifically looked at dyspareunia (pain with sex) showed a significant improvement with the use of cannabinoids.4
- None of the studies analysed in the Whiting et al. article reported any adverse side effects.
I would be remiss not to mention the risks associated with cannabis use. Acute cannabis intoxication may lead to changes with perceptions of time and memory, as well as with motor functions.2 Cannabis may worsen existing anxiety or mood disorders, and it is also associated with the development of psychotic disorders in those with a genetic predisposition to these conditions.2 Other adverse effects of cannabis use may be: drowsiness, confusion, dizziness, fatigue, and disorientation.3 That being said, it is imperative that you speak with your primary care physician to discuss the option of medical marijuana/cannabis use.
Even though there have been strides made in the laws regarding medicinal marijuana/cannabis use, there needs to be a continued push to research the effects of this substance on more specific pain diagnoses, in order to have evidence based studies to back up these claims – to further improve how we treat complex pain conditions including chronic pelvic pain.
I am interested to hear your thoughts and opinions on medical marijuana – what do you think about it? Any personal experiences with using medical marijuana for pelvic pain? You are welcome to share below in the comments!
- Should Marijuana Be a Medical Option? – Medical Marijuana – ProCon.org. Retrieved 9 March 2018, from https://medicalmarijuana.procon.org/
- Hill KP, Palastro MD. Medical cannabis for the treatment of chronic pain and other disorders: misconceptions and facts. Pol Arch Intern Med. 2017;127(11):785-789.
- Whiting PF, et al. Cannabinoids for medical use: A systematic review and meta-analysis. JAMA. 2015;313(24):2456-73.
- Bouaziz J, Bar On A, Seidman D, Soriano D. The clinical significance of endocannabinoids in endometriosis pain management. Cannabis Cannabinoid Res. 2017;2(1):72-80.