People dependent on marijuana who undergo certain surgeries may be at risk of complications, according to a new study. A research team from the McGovern Medical School at the University of Texas Health Science Center recently published the results of the study, which showed those who’ve had a “major elective, inpatient, noncardiac surgery” and had cannabis use disorder were at risk of health complications. 

Researchers found that excessive marijuana use in those undergoing surgery may lead to kidney issues, breathing problems, strokes, blood clots or even death. The study, published in the journal JAMA Surgery, examined data from the National Inpatient Sample database of 12,422 hospitalizations from 2016 to 2019. 

The patients all underwent a major procedure such as:

About half of the patients, more than 6,200 of them, had cannabis use disorder, while the other half were not dependent on marijuana. Those who relied more on the drug were more likely to have complications. Researchers said those with cannabis use disorder saw a 7.73% higher risk of complications compared to 6.57% for patients without the disorder. Those with a dependency for the drug also remained in the hospital longer and had higher hospital bills. 

The University of Texas study recommends that patients be screened for cannabis use and informed about the potential risks before a planned surgery. Researchers say more work is needed concerning cessation of cannabis use prior to surgery before any recommendations can be made. 

Effects of Marijuana on the Body

Past studies by the National Institute on Drug Abuse have shown that almost three out of every 10 marijuana users develop a dependency on the drug. The agency describes a person who is dependent on marijuana as someone who cannot stop using the drug without experiencing withdrawal symptoms such as a lack of appetite, restlessness, irritability, mood swings or trouble sleeping.

The use of marijuana continues to increase across the nation. For most people, cannabis use is considered harmless and it can be medicinal for those looking to ease chronic pain. The full effect of using the drug before an operation is still being studied. 

According to a November 2019 article in the Journal of Clinical Anesthesia, smoking marijuana can have several effects on the body, including: 

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

All of these problems can make recovery from surgery, such as hip replacement, knee replacement or hernia repair, more difficult. An October 2020 study by the University of Colorado found that despite its use for chronic pain, marijuana may actually increase acute pain after surgery. Patients who use marijuana before surgery also need more anesthesia during the procedure.

The lead author of the Colorado study, Dr. Ian Holmen, is an anesthesiology resident at the University of Colorado Hospital in Aurora.

“This study shows that it is important for patients to tell their physician anesthesiologist if they have used cannabis products prior to surgery to ensure they receive the best anesthesia and pain control possible, including the use of non-opioid alternatives,” Holmen said.