Knowledge Base

Cannabinoids

What are Cannabinoids?

Cannabinoids are a group of chemicals that bind to cannabinoids receptors in the human body and help to suppress signals in the brain. This chemical group is divided into 3 major classes: endocannabinoids (naturally produced by mammals), synthetic cannabinoids and plant cannabinoids (as found in marijuana).  There are a number of strains of plant-derived cannabis available.

Marijuana has a long history, dating back thousands of years and has commonly been used for pain relief. Marijuana is a psychoactive drug and its consumption results in a feeling of euphoria; however, the drug may also result in hallucinations and anxiety. 

Other side effects of use may include problems with memory loss and cognition after long term use. Some of the beneficial side effects may include an increase in appetite and the suppression of vomiting, nausea and muscle spasms.
This area of therapy is not well systematically developed at this time. 

How do they work?

There are 2 main types of cannabinoid receptors: CB1 and CB2. CB1 receptors are found in the central nervous system, lungs, liver and kidneys. CB2 receptors are found in the immune system and stem cells. Cannabinoids work by activating cannabinoid receptors and suppressing calcium signals in the nerve cells- thereby reducing pain signals.  

Cannabinoids have been shown to be effective in the treatment of HIV-associated peripheral neuropathy and potentially even diabetic neuropathy. 

What kinds are there?

  • Dronabinol: Dronabinol, also known as Marinol, is a pure form of THC (tetrahydrocannabinol), the main compound found in marijuana.  Dronabinol was shown to be effective in managing neuropathic pain, however, more supporting research is required.   
  • Nabilone: Nabilone, also known as Cesamet, is a synthetic cannabinoid. In a study comparing the effectiveness of nabilone to dihydrocodeine (an opioid), researchers found that the cannabinoid was less effective at managing neuropathic pain. However, the risk of addiction is less with nabilone and the side effects similar to that of the dihydrocodeine. 

Related evidence

Rahn EJ, Hohmann AG. Cannabinoids as Pharmacotherapies for Neuropathic Pain: From the Bench to the Bedside. Neurotherapeutics. 2009 Oct; 6(4): 713-737. doi: 10.1016/j.nurt.2009.08.002.

Vera G, López-Miranda V, Herradón E, Martín MI, Abalo R. Characterization of cannabinoid-induced relief of neuropathic pain in rat models of type 1 and type 2 diabetes. Pharmacol Biochem Behav. 2012 Aug;102(2):335-43. doi: 10.1016/j.pbb.2012.05.008. Epub 2012 May 17.

Ware MA, Wang T. Smoked Cannabis for chronic neuropathic pain: a randomized controlled trial. CMAJ. 2010 Oct 5; 182(14): E694-E701. doi: 10.1503/cmaj.091414

References

Frank B, Serpell MG, Hughes J, Matthews JNS, Kapur D. Comparison of analgesic effects and patient tolerability of nabilone and dihydrocodeine for chronic neuropathic pain: randomised, crossover, double blind study. BMJ. Jan 26, 2008; 336(7637): 199–201. doi:  10.1136/bmj.39429.619653.80

Rudich Z, Stinson J, Jeavons M, Brown SC. Treatment of chronic intractable neuropathic pain with dronabinol: case report of two adolescents. Pain Res Manag. 2003 Winter;8(4):221-4.

Wikipedia [Internet]. Cannabinoid receptor [updated 2014 Sept 6; cited Aug 14]. Available from: http://en.wikipedia.org/wiki/Cannabinoid_receptor

Wikipedia [Internet]. Neuropathic pain [updated 2014 Oct; cited Aug 14]. Available from: http://en.wikipedia.org/wiki/Neuropathic_pain#Cannabinoids



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