People who have major elective surgeries and are dependent on marijuana may be at a higher risk of complications following the procedures, according to a recent study from the McGovern Medical School at the University of Texas Health Science Center.

Researchers found that excessive marijuana use can contribute to serious health problems such as kidney issues, breathing problems, stroke, blood clots or even death. They used data from the National Inpatient Sample database of 12,422 hospitalizations from 2016 to 2019. About 6,200, or half of the patients in the study, had cannabis use disorder and half were not dependent on marijuana. 

All of the patients in the study had one of the following noncardiac surgeries:

Those considered to be cannabis dependent were more likely to have complications, with a 7.73% risk compared to 6.57% for those without a dependency on marijuana. Patients who relied more on the drug also endured longer hospital stays and higher hospital bills. 

Our findings complement previous studies that have identified significant associations between cannabis use disorders and perioperative complications,” study authors wrote.

Researchers behind the study say more work needs to be done before any recommendations about cessation of cannabis use prior to surgery are made. They also suggest that patients be screened for cannabis use and informed about the potential risks before a planned surgery. 

Marijuana Use on the Rise

Cannabis use is increasing across the country. About 18% of Americans report using the drug, according to researchers from the McGovern Medical School. This recent study comes after National Institute on Drug Abuse studies that have shown nearly three out of every 10 marijuana users develop a dependency on the drug.

Some people use marijuana medicinally as a way to treat chronic pain or other conditions. Most consider marijuana use harmless, but its full effects on a person undergoing an operation remains unclear.

A November 2019 article in the Journal of Clinical Anesthesia said that smoking marijuana may have several effects on the body that could pose risks during surgery,  including: 

  • Airway blockage 
  • Decrease in respiration
  • Elevated blood pressure
  • Heart rhythm issues
  • Increase in heart rate
  • Lower body temperature 
  • Reduction in blood flow

All of these conditions can make recovery from major elective surgeries such as hernia repairs, hip replacements and knee replacements more difficult. Also, patients who use marijuana before surgery need more anesthesia during the procedure, according to research. Patients are advised to tell their anesthesiologist if they’ve used any products containing cannabis ahead of a surgery.

Research suggests that marijuana may be able to relieve some pain, but it depends on the situation. An October 2020 study by the University of Colorado found that despite its use for chronic pain, marijuana can actually increase acute pain after surgery. 

“There is some evidence that cannabis may be beneficial for chronic and nerve pain,” Dr. Ian Holmen, an anesthesiology resident at the University of Colorado Hospital in Aurora and lead author of the 2020 study, said in a statement. “However, early research suggests that this is not the case for acute pain such as for surgery of a broken leg.”