Since 2017, as part of an amendment to the Narcotics Act, the use of cannabis in medicine has been permitted under strict conditions. Thus, some selected patients in Germany are allowed to legally buy and use cannabis. However, this has little to do with the cliché idea of “smoking pot on prescription”. This is because numerous studies can prove the scientific benefits of this ancient medicinal plant. Which of the different cannabinoids are used and how they affect our bodies, explains this article.
THC, CBD, cannabis: what is what?
The different names can cause confusion. Cannabis, hemp in German, is a plant that has been cultivated for several thousand years. Even then, cannabis was used in medicine, including for pain or diarrhea. The hemp plant contains several cannabinoids. This is the name given to the chemical substances, the best known of which is tetrahydrocannabinol (THC). The THC content varies from variety to variety, which makes it difficult to determine an exact dosage. Besides THC, another cannabinoid is of importance in medicine: cannabidiol (CBD). In total, more than a hundred different cannabinoids exist, but their exact modes of action are not yet known.
How do cannabinoids work?
Distributed throughout our nervous system are a multitude of cannabinoid receptors. These can be thought of as docking sites on the cell surface. When messenger substances – in this case, cannabinoids – reach the receptors, they connect to the cell surface (much like a key to a lock) and activate the corresponding nerve cell. This allows cannabinoids to trigger a signal in the cell, resulting in reduced release of the inhibitory neurotransmitter GABA. As a result, a second cell can release more dopamine. But these receptors are not only used by cannabinoids supplied “from the outside”; substances produced by the body itself also dock onto these receptors. These substances are called endocannabinoids and have a variety of functions in the body. Among other things, they are involved in immune regulation and pain regulation in the brain. For this purpose, they can dock to different receptors in the body. Basically, we have two different receptors:
- Type 1 cannabinoid receptors: Located mainly in the central nervous system (CNS).
- Type 2 cannabinoid receptors: Are located in a wide variety of places in the body, the digestive organs, skin, lungs or reproductive organs.
Just like the endocannabinoids, THC can act in a wide variety of places in the body. It takes over the function of these natural substances in the meantime.
How does THC affect the body?
The effect of THC on the brain is controlled by cannabinoid receptors. If cannabis is consumed as a drug (either in the form of marijuana or hashish), the cannabinoids are not yet present in their active form. Only by heating a so-called decarboxylation (splitting off of a carbon molecule) takes place and thus the conversion into the psychogenically active THC. This “promotes” among other things in the nucleus accumbens (part of our reward system in the brain) the release of the happiness hormone dopamine. The high amounts of dopamine explain the euphoric effect of the drug. Crucial to the different effects is the level of THC in the blood. While inhalant uses, such as smoking cannabis flowers, produce high levels of 150-180 nanograms of THC per milliliter of blood, medicine does not use such high doses. Most medications provide THC levels of approximately 10 nanograms per milliliter. This is sufficient for the desired medical effect in terms of pain relief, but is too low to get “high.”
In what forms does THC occur in medicine?
In the past, cannabinoids could only be delivered to the body as hashish (pressed resin of the female flowers) or as marijuana (dried flowers). The big problem with this is the varying THC content, which can range from 1 to 20 percent. This wide range and possible impurities made this form of cannabis unusable for medicine for a long time. Nowadays, various products containing THC exist on the market and can be legally purchased by prescription. They differ both in their composition and in their field of application:
- Dronabinol: is administered in the form of oily drops.Dronabinol is thereby a synthetically produced cannabinoid, which can help with loss of appetite.
- Canemes: Is a fully synthetic preparation in which THC is used as capsules for chemotherapeutic nausea.
- Sativex: This drug is used as an oral spray for multiple sclerosis. The active ingredient, nabiximol (a mixture of THC and CBD), is extracted from the cannabis plant.
- Cannabis on prescription: since 2017, all medical professionals (except dentists and veterinarians) are allowed to prescribe cannabis flowers for a given indication. The medical cannabis is imported mainly from Canada and the Netherlands. To achieve the effect, the flowers must be heated beforehand, for example in a vaporizer.
- THC oil: Here, very high concentrations of THC can be achieved, for example, hashish oil a THC concentration of 20 to 60 percent.
Theoretically, a preparation as tea would also be possible. However, due to the poor water solubility of THC, this is not possible The active ingredients in the cannabis flowers are lipohil (fat-loving), so you can store them rather in oil.
Cannabis in medicine – where is it used today?
The diverse action of cannabinoids in our body leads to a wide range of applications of cannabis in medicine. The following conditions may have an indication for therapy with medical cannabis:
- Epilepsies
- Appetite increase in HIV patients
- Nausea and vomiting after chemotherapy
- Chronic pain, especially nerve pain, for which all therapies have failed
- In palliativemedizingegen spasticity in multiple sclerosis.
Side effects of THC
Side effects are particularly psychogenic in nature. Since the mode of action of cannabis is still not fully researched, reliable statements about possible side effects are not yet possible. However, various studies have found that early cannabis use increases the risk of one group of mental disorders, affective disorders. In affective disorder, mood and drive changes occur. An example would be the re-emergence of bipolar disorder, in which individuals fluctuate between manic-euphoric and depressive moods. Other side effects of overdose may include:
- Bad mood up to depression
- Hallucinations
- Vasodilation (vasodilatation) in the eyes, resulting in the typical redness
- Increase in appetite
- Dry mouth
- Tachycardia (rapid heartbeat)
A major advantage in the dosage of cannabis is that there are no cannabinoid receptors in our respiratory and cardiovascular center. Thus, an overdose of THC does not lead to life-threatening situations, as can be the case with other pain medications: For example, when opioids are overdosed, the heartbeat slows to a stop. In addition, the respiratory center becomes paralyzed, so that the affected person can hardly breathe. Furthermore, the muscles can literally dissolve, damaging the kidney. Also beneficial with cannabis is the almost non-existent psychological dependence when administered in the low, medicinal doses.
Cannabis and driving – how long is THC detectable?
Detectability of THC in the blood is only possible for a few hours, as it is rapidly metabolized by the body into various metabolites (breakdown products). However, these THC metabolites can certainly be detected in urine for longer than a few hours, as is done in drug testing. This is a quite reliable method to detect the drug even days after the last consumption. So what about driving ability? In principle, driving under the influence of cannabis is a criminal offense. This has raised the question of whether patients who are prescribed medical cannabis due to their condition should be allowed to participate in road traffic at all. Here, the German government ruled in April 2017 that those affected may participate in road traffic if they are not impaired in their ability to drive.
Conclusion: promising, but still some questions open
The use of cannabis in medicine is still in its infancy. There are still too few scientific studies in the field to make safe statements about its effects. Cannabis is certainly not a miracle drug and it always requires critical questioning in treatment.However, individual cases show promising results.
