Cannabis use is ubiquitous across the nation as states continue to legalize marijuana, both for medicinal and personal uses. Surgery patients who ingest the drug are at a higher risk of complications, which is why surgery center directors and physicians should understand legal, medical, and other implications of cannabis use.

Medical marijuana is a hot topic, notes Ivan Urits, MD, pain medicine fellow, Beth Israel Deaconess Medical Center, Harvard Medical School. “It’s highly controversial, and a lot of people are getting some good benefits out of it, but at the same time it’s in its infancy,” Urits says. “More work has to be done to see what is actually beneficial and what’s not, and whether there is any benefit for various types of pain.”

Federal law prohibiting the sale and use of cannabis has been undercut by state medical marijuana programs and recreational use legislation, says Kathleen Russell, JD, MN, RN, associate director, nursing regulation, National Council of State Boards of Nursing (NCSBN). “What states have done with medical marijuana programs and recreational marijuana laws is create an exception to the federal law,” Russell says. “They say, ‘If you follow these rules, it’s legal in our state, and you can get marijuana at a dispensary.’”

Healthcare professionals should know their state laws and how these might affect their own practices, according to Edward Mariano, MD, MAS, professor of anesthesiology, perioperative and pain medicine at Stanford University. Recreational use of cannabis is increasing as more states legalize marijuana use, he adds. “This is something more and more healthcare professionals are going to encounter,” Mariano observes.

Millions of Americans use marijuana, and its use is widespread among young people.1 In states that have passed medical marijuana legislation recently, healthcare providers and employers might be unsure of how to adjust to the change, notes Brian Garrett, DNP, MSN, RN, CRNA, program director for the Otterbein University OhioHealth Grant Medical Center Nurse Anesthesia Program.

“The Ohio state legislature just allowed medical marijuana use, but it’s not widely accepted yet,” Garrett says. “When something is new, we don’t have a lot of data on it.”

For instance, doctors sometimes would cancel elective surgery cases when patients were regular cannabis users, Garrett notes. “In recent years, this has lightened up where physicians are more likely to do the case,” he says. “They are not routinely testing for it, and it’s provider-specific as to whether they go forward with the surgery.”

The National Institute on Drug Abuse notes that marijuana is gaining greater acceptance in American society in the wake of changing marijuana policies across states.2 The federal government largely is allowing states to set their own policies on marijuana. During the Obama administration, the Department of Justice (DOJ) issued position papers that said the DOJ would not arrest people using or selling medical marijuana according to their states’ laws. This position initially was reversed under the Trump administration, although officials indicated the DOJ would not crack down on states’ legal marijuana industry in response to an objection by U.S. Sen. Cory Gardner, R-CO.3

“The new DOJ memorandum said federal prosecutors should follow their usual rules to determine if they will investigate or prosecute a case,” Russell says. “Since that memorandum, no lawsuits have been filed prosecuting those people who distribute cannabis for medical purposes.”

Legal implications are changing rapidly and vary from state to state. As of December 2019, marijuana use remains fully illegal in only nine states. Surgery centers might keep in mind two of the most important implications of marijuana use:

  • Cannabis use among surgery patients can create a risk when they receive anesthesia;
  • Employers in some states might run into legal trouble if they take action against an employee or potential employee after a positive marijuana drug test.

Another issue is that cannabidiol (CBD), one of the active ingredients of cannabis, is sold over the counter even in states that have not legalized marijuana use. Some of these products include tetrahydrocannabinol (THC), the chemical in marijuana that produces psychological effects. This means employees who use CBD oils, topicals, and other products could test positive on a marijuana screen.

Some employers in Colorado even conduct urine drug screening of patients to prevent problems of cannabis drug interactions with anesthesia products, says Doris Gundersen, MD, medical director and psychiatrist, Colorado Physician Health Program in Denver. “They disclose to patients that they’re screening for THC,” Gundersen explains.

Colorado and some other states leave it up to employers to decide how they handle drug policies and cannabis education for employees.

“Colorado was a canary in the coal mine for legalization of marijuana,” Gundersen says. “Our regulatory agency has done a good job of anticipating regulations for safety, but there is no formal process for healthcare providers to be educated about cannabis. Most providers are doing this on their own.”

Employers conducting pre-employment drug testing will run into situations in which employees test positive for THC when they do not ingest marijuana, but use CBD oil for pain, says Natalie P. Hartenbaum, MD, MPH, FACOEM, president and chief medical officer, OccuMedix in Dresher, PA. “If you use CBD, you run the risk of having a higher level of THC,” she says.4

Healthcare workers who are employed in states where recreational marijuana use is legal might be unaware of the risks they take. For instance, a physician might go to a party and eat a brownie, unaware that it has been laced with marijuana.

“I tell people who work in sensitive positions, and most healthcare providers fall into that category, that there are too many unknown products out there,” she explains. “They should be aware of what is permitted and prohibited in their state.”

Increased use of medical cannabis products also poses risk, says Kannan Ramar, MD, president-elect of the American Academy of Sleep Medicine. “We don’t know, unfortunately, what they actually do and if it is helping patients or causing more side effects,” Ramar says. “The bottom line is we need more studies and rigorously conducted studies that hopefully will guide us.”


  1. National Institute on Drug Abuse. What is the scope of marijuana use in the United States? Available at:
  2. National Institute on Drug Abuse. Letter from the director. Available at:
  3. Office of Cory Gardner. Gardner protects Colorado’s legal marijuana industry, April 13, 2018.
  4. Spindle TR, Cone EJ, Kuntz D, et al. Urinary pharmacokinetic profile of cannabinoids following administration of vaporized and oral cannabidiol and vaporized CBD-dominant cannabis. J Anal Toxicol 2019; Nov 4. pii: bkz080. doi: 10.1093/jat/bkz080. [Epub ahead of print].