In 2016, a lady we'll call Jennie woke up in the middle of surgery. She was getting her wisdom teeth pulled out. She heard a voice say "she's waking up" moments before the anesthesia put her back to sleep. Jennie loves smoking weed. Loves. Gets high once a day, got high before getting surgery.

Little did Jennie know, cannabis might* effect how your body tolerates anesthesia, meaning you may need more than the average person for surgery.

The reason why it "might" effect you differently is complicated.

Cannabis, for now, is still federally illegal making it hard to study. In Colorado, even where it is legal and known usage is estimated to be around 17%, anesthesiologists don't track cannabis specifically against unusual outcomes in a meaningful way.

However, a small 2019 study found that patients who reported smoking weed or ingesting edibles on a daily or weekly basis needed more than double the amount of the anesthetic propofol for endoscopic procedures (like colonoscopies) than non-users. They also needed 19.6% more midazolam and 14% more fentanyl.

To make matters more worse, cannabis, similar alcohol or any other drug, doesn't come in one standard size or dose. Cannabis can range in both THC concentration and chemical makeup which can have different effects on your endocannabinoid system and various parts of your body.

Even if you don’t wake up during a procedure, you can still have issues. If you routinely smoke weed, your airway might be more reactive during anesthesia. You might cough more, experience bronchial spasms, and/or have a more active gag reflex, which is a problem if you need to be intubated, as with general anesthesia (the kind that puts you to sleep) says Jeffrey Uppington, an anesthesiologist at UC Davis Medical Center.

So, if you are a cannabis user and do need surgery, remember that your doctors are under oath to best serve your health needs with all available information given to them without shame or judgement. Suzannah Weiss summed up her experience and key advice to look out for when communicating to your doctor that you take any form of drugs.

Keep in mind: 

• Your doctor breaking doctor patient confidentiality and snitching on you to the police is very unlikely.
• If your doctor expresses concern over your drug use, you also have the right to ask them why. They should be able to explain how exactly the drug you’re using could cause you harm, said Soyona Rafatjah, medical director and co-founder at the primary care and integrative medicine private practice PrimeHealth. If they have a vague explanation like “drugs damage your brain,” that’s a sign that they don’t fully understand the effects of the drug you’re discussing with them.
• "If you ever feel uncomfortable during an appointment with a clinician, you have the right to end the appointment or ask questions regarding the discomfort you feel,” Valerie McDonnell says, a clinical social worker in Virginia who has worked with women with substance use disorders.

Takeaway: 

No matter how often you consume cannabis or how it fits in your life, don’t use it at all on the day of your procedure. Taking an edible on the same day poses the added risk of inhaling it, which may result in a life-threatening lung infection called aspiration pneumonia. Uppington recommends hitting pause for as many days as you can before your surgery, ideally a month, which is how long it takes for cannabis to be fully removed from the body. If that's unlikely to happen, just be honest with your doctor as to your last use.

Recommended Reading:

• How to Tell Your Doctor You're Using Drugs
• Effects of Cannabis Use on Sedation Requirements for Endoscopic Procedures
• If you smoke pot, your anesthesiologist needs to know
• A Simple Guide to the Endocannabinoid System