Cannabis: pharmacology, effects and risks at a glance

Introduction

Cannabis is one of the oldest known useful plants and has been used for various purposes for thousands of years. With the legalization of cannabis in Germany in April 2024, interest in its pharmacological properties, effects and potential risks has increased. This article provides a comprehensive overview of the current scientific findings on cannabis.

The endocannabinoid system

Structure and function

The endocannabinoid system (ECS) is a complex network of receptors, endogenous ligands (endocannabinoids) and enzymes that plays a central role in the regulation of various physiological processes. The two main receptors of the ECS are:

• CB1 receptors: Predominantly located in the central nervous system, particularly in the cerebellum, basal ganglia and hippocampus. They are significantly involved in the modulation of neurotransmitters and influence functions such as pain perception, appetite and memory.

• CB2 receptors**: Mainly found in peripheral tissues and immune cells. They play a role in immunomodulation and inflammatory reactions.

Endocannabinoids such as anandamide and 2-arachidonoylglycerol (2-AG) bind to these receptors and thus modulate various physiological processes.

Phytocannabinoids: THC and CBD

Tetrahydrocannabinol (THC)

Δ9-Tetrahydrocannabinol (THC) is the primary psychoactive cannabinoid in cannabis. It mainly binds to CB1 receptors in the brain and causes effects such as euphoria, altered cognition and increased appetite. In addition to the desired effects, side effects such as anxiety, paranoia and cognitive impairment can also occur.

Cannabidiol (CBD)

Cannabidiol (CBD) is a non-psychoactive cannabinoid that has a low affinity for CB1 and CB2 receptors. It interacts with other receptor systems and is being studied for its potential anxiolytic, anticonvulsant and anti-inflammatory properties. Unlike THC, CBD does not cause intoxication.

Pharmacokinetics of cannabinoids

Absorption and distribution

The way in which cannabinoids are absorbed has a significant influence on their pharmacokinetics:

• Inhalation (smoking or vaporizing): Leads to rapid absorption of THC into the blood, with peak concentrations within minutes. Bioavailability is around 10-35%.

• Oral ingestion (e.g. in the form of edibles)**: Delayed absorption with peak concentrations after 1-3 hours. Bioavailability is lower due to first-pass metabolism in the liver and varies between 4-20%.

Metabolism and excretion

THC is mainly metabolized in the liver by the cytochrome P450 enzyme system, producing the active metabolite 11-hydroxy-THC. Excretion takes place via the stool and urine, whereby THC and its metabolites have a half-life of about 1-2 days. With chronic use, however, they can be detectable in the body for longer.

Acute effects of cannabis

Mental effects

Various psychological effects can occur after consuming cannabis:

• Euphoria and relaxation: Frequently reported pleasant states.

• Changed perception: Changes in perception of time and sensory impressions.

• Cognitive impairment: Short-term memory impairment and reduced ability to concentrate.

• Anxiety and paranoia**: Unpleasant mental states can occur, especially with high doses or inexperienced users.

Physiological effects

Common physical effects include:

• Increased heart rate (tachycardia)

• Drop in blood pressure (hypotension)

• Dry mouth**

• Reddened eyes**

• Increased appetite

Long-term risks and side effects

Dependency potential

Regular cannabis use can lead to psychological dependence. It is estimated that around 4-7% of users develop an addiction. Symptoms can include a strong craving for the substance and difficulty controlling consumption.

Cognitive impairment

Long-term use, especially if it begins in adolescence, can be associated with persistent cognitive deficits. Studies suggest that early and regular smoking can impair academic performance and increase the likelihood of dropping out of school.

Mental illnesses

There is evidence that cannabis use can increase the risk of developing psychosis, especially in genetically predisposed individuals. High doses of THC can trigger acute psychotic symptoms such as hallucinations and delusions.

Respiratory diseases

Smoking cannabis can cause respiratory diseases similar to tobacco smoking, including chronic bronchitis and lung damage. The use of vaporizers or oral dosage forms can reduce the risk of respiratory diseases.

Interactions with other substances

Cannabis can interact with various drugs, especially those that are metabolized via the cytochrome P450 system. This can lead to altered plasma concentrations and effects. It is important to consult a doctor before combining cannabis with other medications.

Conclusion

Cannabis has a complex pharmacological profile with multiple effects on the human body. While some effects can potentially be used therapeutically, risks and side effects must also be considered. Responsible use and sound information are essential to minimize potential dangers and make the most of the benefits of cannabis.