What is medicinal cannabis?

What’s in medicinal cannabis?

The cannabis plant (source)

This is where the confusion starts. There are many different cultivars (or strains) of the cannabis plant, each with different characteristics and uses. There are also many overlapping terms for these plants.

Here’s the short version. Cannabis is a genus of flowering plants. The two main species people generally refer to are Cannabis sativa and Cannabis indica. Each species has distinct characteristics and can produce varying cannabinoid profiles. Within the sativa species, there are multiple strains or cultivars. These also have different cannabinoid profiles.

We’ll get to cannabinoids in a second, but for now, we’re referring to the two main ones, cannabidiol (CBD) and delta-9-tetrahydrocannabinol (THC).

Cannabis plants that contain ≤0.3% THC (the psychoactive compound) are called hemp. These belong to the C. sativa species. Hemp plants are grown for their seeds, fibre and CBD content. Hemp has many industrial uses such as making textiles, paper and biofuel – you might see it referred to as industrial hemp.

If we contrast this with marijuana plants, which can be Cannabis sativa or Cannabis indica, these plants contain >0.3% THC. They are cultivated primarily for their recreational and medicinal properties due to the psychoactive effects of THC.

While the term cannabis covers a lot of different plants, medicinal cannabis (at least for vets) refers to products from the hemp plant.

But medicinal cannabis contains more than just CBD.

Medicinal cannabis components

The cannabis plant contains over 500 compounds – you don’t need to know them all. But to maximise potential benefits to patients, it is worth knowing some key components. And it’s where collaborating with a pharmacist who really knows their stuff is invaluable.

Cannabinoids

Cannabinoids are a group of chemical compounds present in the cannabis plant. There are over 100 known cannabinoids, but the most well-researched and recognised are:

• CBD (Cannabidiol): A non-psychoactive compound, CBD doesn't produce the "high" associated with cannabis. It has multiple potential therapeutic applications, including anti-inflammatory, anti-anxiety, and anticonvulsant effects. In veterinary medicine, CBD has garnered attention for conditions like osteoarthritis, anxiety, and certain types of seizures.

• THC (Delta-9-Tetrahydrocannabinol): The primary psychoactive compound in cannabis. In humans, it's known for inducing euphoria, relaxation, and increased appetite. However, in animals, particularly dogs, THC can be toxic and result in adverse effects like ataxia, hyperesthesia, and urinary incontinence.

Other cannabinoids include cannabigerol (CBG), cannabichromene (CBC), cannabinol (CBN) and tetrahydrocannabivarin (THCV). There are more. Each cannabinoid has its own properties and potential therapeutic benefits. We’re probably a still long way off from high-quality studies of these in veterinary patients.

Terpenes

Terpenes are aromatic compounds found in many plants, including cannabis. They are responsible for the unique scents and flavours of different cannabis strains. Some of the primary terpenes in cannabis include myrcene, limonene, and pinene. Beyond their aromatic properties, terpenes have demonstrated potential therapeutic effects:

• Myrcene: May possess anti-inflammatory and analgesic properties.

• Limonene: Believed to have anti-anxiety and antidepressant effects.

• Pinene: Has potential anti-inflammatory and bronchodilator effects.

Scientific research into cannabis terpenes is still in its nascent stages, but early studies suggest they play a crucial role in the plant's therapeutic properties, potentially influencing the effects of cannabinoids and contributing to the entourage effect (see below).

Flavonoids

Flavonoids are a diverse group of phytonutrients (plant chemicals) found in almost all fruits and vegetables. They are responsible for the vivid colours in many plants and have various health benefits for both humans and animals. The cannabis plant contains around 20 different flavonoids, some of which are unique to cannabis, called cannaflavins.

Cannaflavins have demonstrated potential anti-inflammatory properties. Cannaflavin A, in particular, has been shown to reduce inflammation by inhibiting the production of pro-inflammatory molecules.

Like other flavonoids, those found in cannabis may help combat oxidative stress by neutralising free radicals in the body. This can potentially protect cells from damage and support overall health.

Just like terpenes and cannabinoids, flavonoids may also play a role in the entourage effect, enhancing the therapeutic benefits of other compounds in the cannabis plant.

All together = the entourage effect

The entourage effect is a proposed mechanism by which the various components of cannabis interact synergistically, enhancing the therapeutic effects of each other.

Here's how it may work:

• Complementary actions: Certain compounds can amplify the beneficial effects of others. For instance, terpenes might enhance the anti-inflammatory effects of CBD.

• Mitigating adverse effects: Some components might mitigate the potential adverse effects of others. For example, CBD has been suggested to counteract some of the psychoactive effects of THC.

Basically, the whole cannabis plant's components might work better together than in isolation, making full-spectrum or broad-spectrum products potentially more effective than those containing just a single compound.