Given the increasing prevalence and legalization of marijuana, many patients have come to think that marijuana use is not worth mentioning to their physicians. After all, they reason, I would not necessarily tell my doctor that I had a glass of wine last night, so why should I disclose that I smoked marijuana yesterday? Unfortunately, this reasoning is flawed. Because marijuana has a variety of effects on the body and on anesthesia medicines, it is crucial that anyone undergoing a preoperative evaluation disclose their marijuana use. Don’t worry that your anesthesiologist is judging you. That’s not our job! Our job is to understand your health and body in order to provide you with the safest and most pain-free procedure. This information is part of your confidential medical record, and accurate information is crucial to helping doctors provide good care.
Marijuana can affect the type and amount of anesthesia
The way(s) you use marijuana (smoking, edibles, etc.), how often you use, and how much all can affect how your body responds to anesthesia. Since marijuana and anesthesia both affect the central nervous system, people who use marijuana regularly may need different amounts of anesthesia medicines. In order to know which medicines and how much to use, your doctor needs to know ahead of time how much and how often you use marijuana.
Regular users of marijuana generally need larger doses of anesthesia medicines in order to achieve the same degree of sedation. If you don’t tell your anesthesiologist how much marijuana you smoke, he or she may underestimate how much anesthesia will be needed for you to “go to sleep” and stay asleep during your procedure. For example, compared to nonusers, regular marijuana users (daily to weekly) need over three times as much more propofol to achieve adequate sedation for endoscopies. That is a huge increase in dose that your doctor would want to be prepared to administer.
The higher anesthesia dose required for regular marijuana users can lead to an increased risk of complications, such as decreased blood pressure and delayed awakening from anesthesia.
Marijuana use before surgery can increase the risk of complications
Other side effects of regular marijuana use can lead to serious complications of anesthesia. Inhaled marijuana can affect your lungs and increase phlegm, coughing, wheezing, and the risk of respiratory infections. These lung issues can lead to breathing problems during your anesthetic, such as increased airway sensitivity when the breathing tube is put into or taken out of the airway. This may feel like an asthma attack, with a sensation of difficulty breathing and decreased oxygen getting into the lungs. Regular users of marijuana can also have increased postoperative pain, which leads
