Interactions between cannabis and other substances

Cannabis is not compatible with everything. Here is what you should know before consuming it with other products―medications, tobacco, alcohol, etc.

Cannabis consumption

Cannabis or "marijuana" is a soft drug that comes from a plant with the same name. The consumption of cannabis is widespread and has been legalized in Canada. Although it may seem innocuous, marijuana is a pharmacologically active substance and can therefore have positive or negative effects. It is difficult to predict how a person will feel or react after consuming marijuana. Its effects can be unpredictable, especially for first-time users.

Interactions with cannabis sometimes occur when it is intentionally used simultaneously with other substances in order to obtain effects considered as pleasant. In other circumstances, combining these products occurs not with the intention of seeking this effect, but simply because the context lends itself to it. It is not uncommon for users to remain unaware of the potentially unpleasant effects or the harmful consequences of this type of association.

Cannabis and medications

It is important to use caution when consuming cannabis simultaneously with medications, whether or not they are prescribed. Cannabis can cause side effects similar to those of certain medications. For instance, if marijuana is taken simultaneously with medication likely to cause drowsiness, the effect may be compounded.

Marijuana can also alter the effect of medications, and vice versa. Speak to your pharmacist before you consume marijuana if you are taking medication.

Cannabis and natural products

It is often more difficult to be aware of the risk of interactions when it comes to natural health products. The effects of natural products are generally less well-known and is somewhat rare for the risk of interactions with these products to have been studied. In this context, when these types of products are associated with other substances, including medications or drugs, it is often done without really knowing what might happen.

One might think that, because marijuana is a natural substance, it can be mixed with other products from a natural source without consequence, but, in reality, this is not the case. Just because a substance comes from nature does not mean that it is without danger! It is preferable to speak to a healthcare professional, such as your pharmacist, as soon as you consume cannabis with another substance.

Cannabis and alcohol

Cannabis can cause certain side effects such as drowsiness, dizziness, nausea, decreased vigilance or concentration problems, loss of balance and motor impairment. Alcohol can also cause these types of effects. Combining these two substances results in cumulative effects, which is not advisable and increases the risk of unfortunate consequences.

It should be noted that it is prohibited to drive a vehicle when a person is under the influence of cannabis, just as it is when a person’s faculties are under the influence of alcohol.

Cannabis and tobacco

Combining marijuana and tobacco is widespread. Many people blend marijuana with tobacco before smoking it. It is important to know that the effects of both these substances are additive and can even be compounded.

Note that the nicotine contained in tobacco and tetrahydrocannabinol (THC), an active compound in cannabis, both cause the release of dopamine in the brain’s “reward pathway”, which explains why these substances are so addictive.

Cannabis and street drugs

Street drugs are among the most common substances used simultaneously with marijuana. This association represents a clear danger to health due to the possibility of cumulative effects and to the fact that THC increases the risks of toxicity of certain drugs.

Additionally, it is a well-known fact that street drugs have a strong potential for addiction. A user that combines several different drugs has a higher risk of getting "hooked".

Cannabis and food

Consuming cannabis orally is a rather common practice. It can be incorporated as an ingredient in various recipes.   This method of using cannabis is not contraindicated; however, keep the following in mind:

  • The absorption of ingested cannabis is slow and irregular. The effects of the drug are delayed and become more unpredictable; they can also be stronger and last much longer than when the substance is inhaled.
  • The dosage of the ingested product is less defined, which increases the risk of overdose, even intoxication. Great caution is advised to protect the health of cannabis users, their loved ones and their pets.

Cannabis use during pregnancy and breastfeeding

It has been shown that THC passes through the placenta and breast milk. The consequences of THC exposure in the foetus or a breastfed baby are currently unknown. Therefore, pregnant women or breastfeeding mothers should abstain from smoking or ingesting cannabis.

Cannabis use involves risks and warrants a note of caution.  Interactions of this drug with other substances represent a significant issue that must be considered. Don’t hesitate to speak to your pharmacist if you have any questions about cannabis!


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Interactions between cannabis and other substances

Cannabis is not compatible with everything. Here is what you should know before consuming it with other products―medications, tobacco, alcohol, etc.
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