What are the risks and side effects of medical cannabis (CBD and THC)?

by | Aug 16, 2021

Almost everything we put into our bodies comes with potential side effects — from the coffee you drink each morning to the medicine you take for a common cold.

Medicinal cannabis is no exception.

While cannabis can have many wonderful therapeutic benefits for a wide range of health conditions, some people can experience side effects.

Side effects can range from mild to severe and vary from person to person.

Many people won’t experience side effects at all.

If you’re thinking of using medicinal cannabis, it’s important to understand the potential side effects so you can make an informed decision.

The more you know about the effects of medicinal cannabis, the more safe and effective your experience will be.

 

Understanding the side effects of medical cannabis

Cannabis is one of the few medicines where the side effects have been studied as much as — if not more than — the desired effects.

However, a lot of this research has focussed on smoked recreational cannabis, rather than medicinal cannabis which can be consumed in many different ways.

In this article, we’ll be focusing on medicinal cannabis that you can obtain with a prescription from a doctor.

With these medicines, you know exactly what cannabinoid blend and dosage you’re getting so you can better anticipate the potential side effects.

 

What causes side effects?

When it comes to medicinal cannabis, the main factors that determine side effects are:

  • The type of cannabis medicine you’re using (CBD, THC, whole cannabis)
  • The dosage (how many milligrams [mg] a day)
  • The consumption method (oil, tincture, pill, capsule, balm)
  • Who you are (your genetics, biology, physiology, pre-existing conditions)

To better understand side effects, let’s jump back to the coffee example at the start of this article.

Let’s say Person A has a black coffee with 95mg of caffeine at 7.30am and feels alert, focussed, and slightly dehydrated.

Person B has a flat white with 75mg of caffeine at 2.30pm and feels anxious, agitated, and has trouble sleeping that night.

Person C has three lattes between 9am and 2 pm, each with 100mg of caffeine, and feels energised, but has a slight headache and difficulty concentrating.

In those examples, alert, focussed and energised are the desired effects of coffee while feeling dehydrated, anxious, agitated, and having trouble sleeping, a headache, and difficulty concentrating are side effects.

Everyone you know probably responds to caffeine in slightly different ways because we’re all slightly different people.

But individual responses to caffeine are highly influenced by the type of coffee consumed, the number of coffees consumed, and the amount of caffeine in the coffee.

The same is true for medicinal cannabis.

The desired effects and side effects are caused by the interplay of several different factors, which is why it’s important to talk to your doctor and get a prescription for the medicine and dosage that’s right for you and your health condition.

 

CBD and THC: What’s the difference?

CBD and THC are the two “main” cannabinoids in cannabis and each has unique effects and side effects.

Most medicinal cannabis products can be divided into two categories: CBD products (which can have very small amounts of THC), and THC:CBD blends that contain varying amounts of both cannabinoids.

The main difference between CBD and THC is that THC can have an intoxicating effect while CBD does not. However, the cannabinoids are different in many other ways as well.

There are hundreds of other cannabinoids in the cannabis plant and many of them have therapeutic and clinical potential.

In future, there will be a wider variety of cannabinoid medicines, but for now, we’ll be focusing on CBD and THC.

 

What are the side effects of CBD?

What are the risks and side effects of medical cannabis (CBD and THC)?

CBD is generally well-tolerated and safe, but some people do experience side effects, especially when taking CBD orally (oil, tincture, pill).

The most commonly reported CBD side effects are:

  • Dry mouth
  • Fatigue
  • Drowsiness
  • Reduced appetite
  • Irritability
  • Diarrhoea
  • Lower blood pressure

These side effects are generally short-term, which means they will disappear when the effects of the CBD wear off.

Higher doses of CBD are more likely to cause side effects, so it’s advisable to start with a low dose to see how you tolerate it. You may find that different consumption methods also influence side effects.

If you are using CBD topically as a skin cream, balm, or oil, it’s highly unlikely you’ll experience any of these side effects. However, there are isolated cases of CBD causing skin irritation.

Many of these side effects are common across a wide range of medications, not just medicinal cannabis.

 

What are the side effects of THC?

THC causes more side effects, but these are mostly mild, well-tolerated, and short-term.

The most common side effect of THC is the “high” or “stoned” feeling that cannabis is known for. This feeling can range from euphoria, relaxation, hunger and amusement to anxiety, confusion, paranoia and nausea. It depends on the amount of THC consumed, how it’s consumed, and your tolerance level.

Many medicinal cannabis blends don’t contain enough THC to produce a strong high, but some may have intoxicating effects. CBD can also help to counteract the psychoactive effects of THC, providing a more balanced experience.

Other common side effects of THC are:

  • Dry mouth
  • Itchy/dry/red eyes
  • Dizziness
  • Impaired coordination
  • Increased anxiety/paranoia
  • Sleepiness/drowsiness

New users of high-dose THC may also experience tachycardia (increased heart rate).

High-dose THC has also been linked to a higher risk of psychosis and schizophrenia, particularly for teenagers, pregnant women, and people already at risk of mental illness.

To reduce the chances of adverse effects, you should always start with a low dose of THC to assess your tolerance and increase the dosage if needed. Your doctor can help you choose the best medication and dosage for you.

 

Weighing up the effects

What are the risks and side effects of medical cannabis (CBD and THC)?

The important thing to keep in mind when weighing up the benefits and risks of medicinal cannabis is that all medications have potential side effects.

A standard painkiller that you can buy from the supermarket can cause stomach pain, heartburn, diarrhoea, nausea and more, but many of us use it without a second thought.

Medicinal cannabis comes with potential side effects, but in most cases it’s safe and well-tolerated.

The best thing you can do is talk to your doctor about the potential side effects and decide on a suitable treatment plan together.

A good rule of thumb is to start with a low dosage, go slow, and tweak your treatment based on how you feel.

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