Cannabis and Anesthesia

Having a procedure? Cannabis consumption should be part of the conversation.

Doctors Anesthetizing a women before surgery Source: Shutterstock

Both cannabis and anesthesia affect your central nervous system, but does that mean your anesthesiologist needs to know about your last toke? 

The short answer is yes. Marijuana can affect your intake of anesthesia during surgery.  

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Alerting your health care practitioner about your cannabis use might sound like an intimidating conversation to have, but it’s an important act of self-advocacy. Your doctors and anesthesiologists can’t give you the appropriate care if they don’t have an accurate picture of your overall health, including the last time you consumed cannabis. 

Cannabis Consumers Need More Anesthesia 

Remember that one medical drama when the patient woke up in the middle of surgery? Well, if you consume cannabis daily and don’t let your doctor know before you go under, that frightening and painful experience could happen to you. 

Frequently using cannabis can significantly impact your tolerance to anesthesia. According to one doctor writing for Harvard Health Publishing, “compared to nonusers, regular marijuana users (daily to weekly) need over three times as much more propofol to achieve adequate sedation for endoscopies.” 

That’s a massive difference in dosing. Unless you want to feel every second of your upcoming colonoscopy or begin gagging in the middle of an endoscopy, let your doctor know exactly how often and how much cannabis you consume. This information will help your doctors provide you with enough sedation to put you out (and keep you out). 

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Smoking weed doesn’t only impact anesthesia’s potency. If you use cannabis regularly, you should also be aware of the potential physical side effects of consuming the day before or the day of your procedure. 

Risks of Using Cannabis Right Before Surgery 


Weed relieves stress, and surgery is stressful. But consuming cannabis immediately before surgery can interfere with the anesthesia and even lead to serious side effects, including the following:

  • Increased phlegm production
  • Coughing
  • Wheezing
  • Respiratory infections
  • Difficulty breathing 
  • Increased airway sensitivity to the breathing tube
  • Increased postoperative pain
  • Difficulty sleeping during the postoperative period 
  • Anxiety, paranoia, or psychosis upon waking up post-surgery

Ingesting edibles before surgery is particularly dangerous. Edibles can produce intense, long-lasting effects in the central nervous system. Additionally, the American Society of Anesthesiologists recommends that patients fast from solid foods six to eight hours before surgery to prevent the inhalation of food into the patient’s lungs. So ingesting edibles poses a double risk: the risk of reduced anesthesia potency and accidental food inhalation.  

Cannabis consumption can also lead to hypotension (low blood pressure) and an increased heart rate. This combination can trigger a heart attack in patients with compromised cardiovascular health and is an elevated risk in patients who are under anesthesia. 

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How to Tell Your Doctor About Your Cannabis Use Before Surgery 

Your doctor or a nurse will ask you to complete a survey before your procedure. Inevitably, there will be a section devoted to your alcohol or drug use. If you’re going to undergo a procedure in which anesthesia is necessary, answer these questions honestly. 

Medical cannabis is legal in most states. It’s lost most of its social taboo, which means that some patients might genuinely think it unimportant to share their cannabis use with their surgeons.  

Other cannabis users may worry that their doctors will judge them or, worse, report them if they live in a state where consumption remains illegal. 

But the Health Insurance Portability and Accountability Act (HIPAA) protects your doctor-patient confidentiality. HIPAA is a set of heavy regulations safeguarding personally identifiable health information, and HIPAA violations can result in civil and criminal penalties. In other words, your doctor can be on the hook to pay up to $1.5 million in fines and serve up to ten years in prison for spreading your business. 

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A doctor and patient dicussing something while sitting at a table

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Even if HIPAA wasn’t standing between your privacy and someone else’s meddling, most doctors aren’t interested in getting you in trouble or making judgments about your lifestyle. The number of people who accept cannabis as a beneficial therapy is growing, and large swaths of that population belong to the medical community. Doctors, nurses, anesthesiologists, and other health care workers want to do their jobs effectively (and most don’t see a problem with cannabis). 

Letting your doctors in on your cannabis routine helps them give you safe guidelines as you prepare for your surgery. Your doctor will likely ask you to abstain from all cannabis use for at least 72 hours before surgery to play it safe. Since cannabis can directly impact how your body metabolizes anesthesia, we recommend that you follow your doctor’s instructions and take a few days off weed. 

As difficult as it might feel, let your doctor know if you consume cannabis on the day of surgery. There’s a time and a place to use eye drops and spray Febreeze to cover up your weed use, but the day of surgery is not it. Worst case scenario, your doctor will ask you to reschedule your procedure. That’s a small price to pay considering the potential side effects of going under anesthesia while high. 

We aren’t medical professionals — the information on this page is not meant to be a substitute for your doctor’s advice. Talk to your health care practitioner before incorporating cannabis into your wellness routine, especially if you have an upcoming surgical procedure requiring the use of anesthesia. 

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