As the usage of cannabis products has become more and more common, many may overlook telling their physician about how they use the substance. After all, why would you tell your physician if you had a glass of wine last night? However, as cannabis has a number of effects on the body, and interacts with anesthesia medicines, it is crucial that your doctor knows about your cannabis use prior surgery.

As cannabis and anaesthesia both affect the central nervous system, people who use cannabis may need different quantities of anesthesia medicines. To understand how best to dose them, and even which best to use, doctors need to know both how much and how often you use cannabis products.

Those who use the substance regularly generally require larger amounts of anesthesia medicines than those who do not. This means that, should you fail to tell your clinician about your cannabis usage prior to surgery, they may prepare an insufficient amount for you to properly ‘go to sleep’ during the procedure.

And the difference could be huge. People who use cannabis on a daily to weekly basis typically need more than three times the quantity of propofol to become sedated for endoscopies (the insertion of a long thin tube to inspect internal organs) than those who do not use the substance.

More than this, taking anaesthesia as a regular cannabis user may put you more at risk of negative side effects. To begin, as higher doses are needed for proper sedation, cannabis users are at a higher risk of decreased blood pressure and delayed awakening.

Furthermore, as inhaling cannabis from smoking leads to inflammation of the respiratory tract, some may experience breathing problems while under anaesthetic. Should an endoscopy happen, it may also increase the likelihood of something that feels like an asthma attack as less oxygen is able to reach the lungs.

A lot is yet to be known about the effects of cannabis on surgical procedures, and as it is still a classified drug, research about this will be limited for the foreseeable future. Thus, until more information is available, anesthesiologists recommend informing your physician about your usage of the substance before surgery.

Sources: Harvard Health, PMC