You likely know that a procedure requiring anesthesia comes with guidelines beforehand. Doctors will instruct patients not to eat or drink six to eight hours before and avoid even sipping water to take medications unless necessary. This is because any substances present in the stomach can go into the lungs during the procedure. This is known as aspiration, which can be serious and possibly even fatal.  Despite the concerns that come with ingesting any substances before surgery, only recently has evidence emerged about the risks of marijuana use and anesthesia.  If you or a loved one use marijuana and have a procedure requiring anesthesia on the horizon, read on to understand why abstaining before surgery is important. 

Why can’t I use marijuana before surgery?

There are several reasons why marijuana use can cause problems when it comes to anesthesia including:

• Need more anesthesia to fall and stay asleep: A patient who uses marijuana in any form before surgery usually needs a higher dose of anesthesia to put them to sleep. In a study reported by the American Society of Anesthesiologists, researchers found those who used marijuana before surgery needed nearly 50% more anesthesia during their procedure. The amount can fluctuate based on the frequency of marijuana use. If you or a loved one uses marijuana before surgery and do not disclose the correct details to the anesthesiologist, it’s possible to receive an incorrect dosage. This raises the risk of not falling asleep and staying asleep properly.
• Experience more pain: Additionally, patients who use marijuana before surgery may experience more pain while in recovery than those who do not. This can lead to an increased need for opioid pain relievers post-surgery.  
• More complications: Smoking marijuana is also linked to a greater risk of complications during surgery related to the lungs. In addition, marijuana use can also cause low blood pressure and an increased heart rate, which is also dangerous during surgery.
  Further, it’s very important not to use edible marijuana products before anesthesia, as this can cause the same serious damage to your lungs as eating food and drinking can.  

Because we are still learning more about the effects on the body of marijuana and anesthesia it’s best to consult with your anesthesiologist and abstain from use before surgery.