Cannabis has been used therapeutically in many cultures for centuries. It was also widely used in Europe until the late 19th century to treat pain, spasms, asthma, sleep disorders, depression and loss of appetite. It was not until 1929 that cannabis and drugs based on it were banned in Germany by the "Law on the Traffic in Narcotics (Opium Law)", the forerunner of today's Narcotics Law (BtMG).
In the second half of the 20th century, cannabis in medicine lost its importance worldwide, mainly due to a lack of evidence as well as medical progress and the development of special pharmaceuticals for almost all areas of application of medicinal cannabis. Another turning point in the 1990s was the discovery of the body's endocannabinoid system with its cannabinoid receptors.
In the years that followed, reports of seriously ill patients who were able to significantly improve their subjective quality of life through the consumption of cannabis increased - despite still not clear study situation. In Germany, the self-cultivation of cannabis for medical purposes as well as the purchase from the pharmacy for some patients were permitted by a special permit from the Federal Institute for Drugs and Medical Devices (BfArM), which also brought the topic into the social focus and brought pressure
on politicians to act.
As a result of the “Cannabis as Medicine” law, which was finally passed unanimously by the German Bundestag on January 19, 2017, cannabis can again be prescribed for medical purposes on a health insurance prescription in Germany since March 2017. In 2018, a good 60,000 people were already supplied with a total of 95,000 prescriptions for cannabinoid medicines.
The term 'cannabinoids' refers to a heterogeneous group of pharmacologically active substances that have an affinity for the cannabinoid receptors in the human body. A distinction is usually made between synthetic and endogenous (i.e. formed in the human body) cannabinoids and those of plant origin, for example in the hemp plant - the so-called phytocannabinoids. The most important of the more than 100 known phytocannabinoids in the medicinal use of cannabis are Δ⁹-trans-tetrahydrocannabinol (THC) and cannabidiol (CBD).
Due to its psychotropic effect, Δ⁹-trans-tetrahydrocannabinol, THC for short, is largely responsible for the "typical" effects of cannabis, especially its psychoactivity. Studies have already shown numerous therapeutically useful effects of the cannabinoid, including:
Tic-reducing in patients with Tourette's syndrome
sedative (depending on dosage)
synergies in combined therapy with opioids, which can reduce the amount of opioids to be taken and their side effects
In contrast to THC, cannabidiol, or CBD for short, is only very weakly psychoactive and therefore has hardly any intoxicating effects. It is therefore not considered a narcotic, but it does have some medically valuable properties and can work in the following ways, among others:
sedative and spasmolytic
antiemetic, anticonvulsant, neuroprotective, antiphlogistic
Patients with treatment-resistant forms of epilepsy and other neurodevelopmental disorders also report an improved quality of life through treatment with CBD, usually without any serious side effects. The effect of cannabidiol is also described as being opposite to THC and can thus mitigate its side effects when used in combination.
Terpenes and terpenoids are a broad spectrum of chemical compounds found in fruits, fungi, and numerous other organisms, including cannabis. Over 100 different terpenes have been identified in cannabis plants, and the terpene profile of an individual plant can vary greatly depending on the growing conditions.
Terpenes are largely responsible for the aroma of a cannabis plant, but they can also have a wide range of medicinal uses. The high number of existing terpenes and the different interactions they have both with each other and with cannabinoids such as THC and CBD mean that cannabis flowers and whole cannabis extracts can have very different effects depending on the strain.
For therapeutic practice, this holds a multitude of possibilities, since the treatment can be individually adapted to the needs of the patient and unwanted side effects can be reduced through a selective and targeted choice of cannabis flowers.
The entourage effect describes medically useful synergies that can arise when terpenes and cannabinoids are combined. It can both improve the bioavailability and solubility of therapeutically useful components of the cannabis plant via pharmacokinetic effects and contribute to a combined effect on various therapeutic target structures.
Medical cannabis can be given to patients in different ways. The most suitable drug and the form of administration are strongly dependent on the indication and the patient and should be found together by the doctor and patient, taking into account the symptoms and individual accompanying circumstances.
Cannabis flowers are the most common dosage form of medicinal cannabis worldwide. The flowers of the Cannabis sativa plant are delivered to pharmacies in dried form and then given to patients either granulated or not crushed. At the beginning of a therapy with cannabis flowers, the inter-individual fluctuations in the effect of a variety can make a certain "try-and-error" phase necessary, during which the patient tries out different cannabis flowers with regard to effects and possible side effects in order to find the optimal drug for themselves to find.
Medicinal cannabis flowers can be applied in two different ways:
Vaporization using a vaporizer for inhalation
Tea preparation for oral consumption
Especially in the area of recreational use, the varying effects of different cannabis varieties are still often associated with the botanical genus of the plant (sativa, indica, ruderalis) - but this is not tenable from a scientific point of view. Rather, it is the "fingerprint" of each cannabis plant that determines its effect and results in particular from the individual terpene profile described above and the cannabinoid composition.
Onset and duration of action of cannabis medicinal products
The onset and duration of action of medical cannabis depend heavily on the selected therapeutic agent and the form of administration.
The effect of inhalation after vaporization of cannabis flowers starts after a few minutes and lasts up to four hours.
When taken orally - for example a cannabis full extract - it often takes 30 to 90 minutes for the effects to occur, which then usually last longer.
Therefore, when choosing the drug and the form of administration, the symptoms to be treated should always be kept in mind - for example, acute pain attacks can of course be treated much more effectively with an immediate therapeutic agent than with one where the effect only occurs with a time delay.
Possible side effects of cannabis therapeutics
Cases of life-threatening complications after cannabis poisoning are not known in humans. In studies with monkeys, no deaths occurred even after administration of 9,000 mg THC per kilogram body weight.
Nevertheless, cannabinoid drugs can lead to undesirable side effects, the intensity of which depends heavily on the dose administered, as with other psychotropic drugs. Especially with dronabinol and cannabis flowers and extracts with a high THC content, it is therefore advisable to start treatment with a rather low dose and then gradually increase it.
Possible side effects include:
psychological changes such as anxiety, nightmares and paranoia
palpitations and tachycardia
vasodilation and hypotension
Disorders of the digestive tract such as abdominal pain, nausea and diarrhea
Drowsiness, blurred vision and dizziness
Contraindications for treatment with cannabis are in particular severe diseases of the cardiovascular system, hypersensitivity to THC, pregnancy/lactation, personality disorders and certain mental and psychotic diseases.
Most interactions with other therapeutics are pharmacodynamic in nature. The sedating properties of certain drugs can be enhanced when combined with THC.