Cannabis products for pain

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The history of cannabis as a painkiller

The analgesic properties of cannabis have been known for thousands of years. The oldest evidence of the plant's medicinal use was discovered in China, where it was used primarily to treat rheumatic pain, but also constipation and malaria. In addition, the famous Chinese physician Hua T'o (110-207 AD) is credited with having used the cannabis plant together with wine to anaesthetise patients during surgical procedures.

From around 1000 BC, cannabis was also used in India. Here, however, the plant was not only used to relieve nerve pain, headaches, toothaches and other ailments, but also for religious rites. Later, cannabis also spread to the Middle East, Africa and America, and its analgesic effect on earaches, toothaches and menstrual cramps is also reported in these regions¹.

In Europe, cannabis was first cultivated to obtain fibres for the production of ropes, textiles, etc.. However, from the 19th century onwards, cannabis was also used in Europe in a medicinal context. One of the properties of cannabis described in the literature in the 20th century was its pain-relieving effect, and there were already corresponding products sold in pharmacies¹.

In 1925, cannabis was finally banned by an agreement of the Second International Opium Conference in Geneva².

This laid the foundation for the restrictive drug policy worldwide and also prohibited the use of cannabis medicines. In some countries, however, medicinal cannabis is allowed again today. Therefore, international research teams can also devote more attention to the benefits of medicinal cannabis preparations again. Today, chronic pain is the most common indication for the prescription of cannabis in Germany.

How does cannabis work as a painkiller?

Experts believe that the effect of cannabis on pain can be explained by the fact that cannabinoids such as THC and CBD interact with the body's endocannabinoid system³.

The endocannabinoid system

The endocannabinoid system (ECS) is a regulatory system consisting of receptors for endogenous cannabinoids. These so-called endocannabinoids can activate the receptors on demand and influence certain processes. These processes include the sensation of pain, the regulation of emotions, sleep and the immune system.

In addition, the active substances of the cannabis plant (phytocannabinoids) can also bind to these receptors, activate them and therefore cause similar effects. In total, the cannabis plant contains more than 100 cannabinoids, of which only a few have been researched so far. THC and CBD are the most abundant and the best studied phytocannabinoids.

The most important receptors are cannabinoid receptors 1 (CB1) and 2 (CB2). Both are thought to have analgesic effects when activated. CB1 is very abundant in the central nervous system, while CB2 is very abundant in immune cells. Both receptors are distributed throughout the body³.

For which types of pain is medical cannabis used?

Medical cannabis is not a panacea - and should therefore be used with caution. Most prescriptions for medical cannabis are for chronic pain, and the effect on neuropathic pain in particular is supported by scientific studies.  Whether cannabis is effective for acute pain is rather doubtful ^4,5,6,7.

The effect of cannabinoids on chronic pain

THC is thought to be the main analgesic cannabinoid, but CBD also contributes to the analgesic effect. Moreover, the combination of these two cannabinoids seems to enhance the positive effects while reducing unwanted side effects of THC. One of the mechanisms involved in the analgesic effect of cannabinoids is the reduction of the release of neurotransmitters by neurons, which alters the sensation of pain⁸.

Studies provide evidence that cannabis is not classically analgesic. Rather, it contributes to patients perceiving the pain as less disturbing⁹. The pain does not disappear, but is perceived as less unpleasant through cannabinoid therapy.

How are cannabis preparations used for pain?

Cannabis can be a valuable support in pain therapy. Cannabinoids can be prescribed as a supplement to regular painkillers, e.g. opioids. Especially patients who do not get sufficient relief from conventional therapies can benefit from the possibilities of a complementary cannabinoid therapy.

For people who suffer from the sometimes very unpleasant side effects of opioids, pain therapy with cannabinoids can also bring advantages¹⁰. Optimally, the dosage of opioids can be reduced due to the altered pain perception, which in turn can reduce side effects and the risk of opioid dependence.

Other benefits

Several studies also suggest that phytocannabinoids may mitigate the side effects of strong painkillers and secondary symptoms of chronic diseases:

• Nausea and vomiting are a common side effect of opioid therapy. Studies on cannabis treatment during chemotherapy have shown that cannabis could alleviate nausea and vomiting⁶.
  
• Some patients suffer from loss of appetite and weight loss due to prolonged severe pain, and reduced appetite is also a common side effect of opioid pain therapy.  Cannabis has been shown to stimulate appetite⁶.

• Many pain patients suffer from depression as a result of their chronic pain.  According to a German study, 2.8 % of cannabis medications are prescribed for depression⁵.

• Sleep disorders are not uncommon among people with chronic pain and are an additional burden. Research teams point to the possible sleep-promoting effect of medical cannabis¹¹.

Forms of application of cannabis against pain

Cannabis medicines are available in different forms of application:

• Inhalation: If the cannabis preparations are absorbed through the lungs, they quickly enter the bloodstream and ensure that the effect occurs quickly. Due to the carcinogenic combustion products of smoking, medical professionals recommend inhalation with a vaporiser.
  
• Oral intake: Medical cannabis preparations are also produced as medicines for oral intake. Patients can take the medicine in the form of tablets, capsules, oils or alcoholic tinctures. Pain patients often prefer to take the medicine orally because of the exact dosage and the longer duration of action.

• Oromucosal application: Another form of application is absorption through the oral mucosa.  In this case, drops are placed under the tongue. In this way, the activated substances pass directly into the bloodstream and bring with them rapid effectiveness; in addition, part of the medication is swallowed and absorbed via the digestive tract.

References

1. 1Zuardi, A. W. History of cannabis as a medicine: A review. Revista Brasileira de Psiquiatria vol. 28 153–157 (2006).
2. 2Kirsten R. Müller-Vahl, Franjo Grotenhermen; “Cannabis und Cannabinoide in der Medizin” Medizinisch Wissenschaftliche Verlagsgesellschaft, Berlin 2020, S. 218
3. 3Anthony, A. T., Rahmat, S., Sangle, P., Sandhu, O. & Khan, S. Cannabinoid Receptors and Their Relationship With Chronic Pain: A Narrative Review. (2020).
4. 4Kirsten R. Müller-Vahl, Franjo Grotenhermen; “Cannabis und Cannabinoide in der Medizin” Medizinisch Wissenschaftliche Verlagsgesellschaft, Berlin 2020, S. 138
5. 5Abschlussbericht der Begleiterhebung nach § 31 Absatz 6 des Fünften Buches Sozialgesetzbuch zur Verschreibung und Anwendung von Cannabisarzneimitteln https://www.bfarm.de/DE/Bundesopiumstelle/Cannabis-als-Medizin/Begleiterhebung/_node.html;jsessionid=C8FE79E517C28C0C0ACFEEDEA12CA3A2.internet282
6. 6Bilbao, A. & Spanagel, R. Medical cannabinoids: a pharmacology-based systematic review and meta-analysis for all relevant medical indications. BMC Med 20, (2022).
7. 7The National Academies of Sciences Engineering and Medicine (U.S.) Comittee on the health effects of marijuana: an evidence review and research agenda. The health effects of cannabis and cannabinoids: the current state of evidence and recommendations for research. Washington, DC: the National Academies Press (2017).
8. 8Ferro, E. S. et al. Cannabinoid Therapeutics in Chronic Neuropathic Pain: From Animal Research to Human Treatment. (2021).
9. 9de Vita, M. J., Moskal, D., Maisto, S. A. & Ansell, E. B. Association of Cannabinoid Administration With Experimental Pain in Healthy Adults: A Systematic Review and Meta-analysis. JAMA Psychiatry 75, 1118–1127 (2018).
10. 10Boehnke, K. F., Litinas, E. & Clauw, D. J. Medical Cannabis Use Is Associated With Decreased Opiate Medication Use in a Retrospective Cross-Sectional Survey of Patients With Chronic Pain. J Pain 17, 739–744 (2016).
11. 11Walsh, J. H. et al. Treating insomnia symptoms with medicinal cannabis: a randomized, crossover trial of the efficacy of a cannabinoid medicine compared with placebo. Sleep 44, (2021).

Disclaimer and legal notice

This article is for informational purposes only and does not replace medical advice from a doctor. The content is not intended to motivate self-diagnosis or self-treatment, nor to tempt people to change their own medical treatment. Canify Clinics does not make any recommendations or promote any diagnostic methods or treatments. If you wish to change your treatment, this should always be discussed with a doctor. Furthermore, Canify Clinics cannot guarantee the accuracy, timeliness and balance of the content. Therefore, neither the authors of the texts nor Canify Clinics accept any liability for damages that may arise from the independent use of the information described here.