Does marijuana interfere with general anesthesia?

Answer 1

Not from my experience, and I've been under anesthesia at least twice while high. Pretty non-reactive stuff, that THC. It's very similar to chemicals in the brain (which were discovered after THC and named after it, endo-cannabinoids), so i doubt there would be any cross effects. Maybe increased chance of nasuea afterwards, but that would be it.

Anesthesiologists are conducting research to determine exactly how certain herbs and dietary supplements interact with certain anesthetics. They are finding that certain herbal medicines may prolong the effects of anesthesia. Others may increase the risks of bleeding or raise blood pressure. Some effects may be subtle and less critical, but for anesthesiologists anticipating a possible reaction is better than reacting to an unexpected condition. So it is very important to tell your doctor about everything you take before surgery.

Source: http://lifelinetomodernmedicine.com/faqs.aspx#herbal

Answer 2

It is critical that patients quit smoking all substances before surgery, including marijuana; these substances can have the same detrimental effects on surgery as nicotine. For example, they can make patients more or less susceptible to anesthetics. The carbon monoxide found in any kind of smoke affects blood pressure, making it more difficult for the blood to carry oxygen.

Patients should feel comfortable telling their anesthesiologist if they have been smoking or using other substances before surgery, as this information will remain confidential and is important to their care.

Source: http://www.lifelinetomodernmedicine.com/ArticlePage.aspx?ID=0f8af670-3cfb-47c3-b9f0-b54eb8f4528d&LandingID=fc6eb1da-98e4-43c7-bb9f-09c17e2a005d