This is the first of a two-part series in which Meredith Fisher-Corn, MD, recommends questions one must ask their healthcare provider when it comes to cannabis.
In October 2018, the Canadian federal government legalized the use of cannabis for both medicinal and recreational purposes, and you may be one of the millions of Canadians who utilize cannabis or are considering it.
So, do you actually need to talk to your doctor and other healthcare providers about cannabis? YES! In order to best manage a patient’s medical care, clinicians need to know about all medicinal and recreational drugs a patient is utilizing, including cannabis. Considering that the Canadian government has legalized cannabis use, view cannabis in the same fashion as you view any other legalized medications.
Not sure how to start the conversation? Here are some questions (with the answers) you may want to discuss with your doctors, pharmacist, nurse and other healthcare providers.
Does it matter if I smoke, vape, or ingest cannabis… aren’t the effects the same?
The effects of cannabis are, in part, dependent upon the way in which it is consumed.
When cannabis is smoked or vaporized, delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), as well as many other components of the cannabis plant are inhaled and quickly pass from the lungs into the bloodstream and readily cross the blood-brain barrier. Psychoactive effects appear within seconds to a few minutes of inhalation, typically reach a maximum after 15-30 minutes, and taper off within two to three hours.
In contrast to vaporizing, smoking cannabis is associated with several negative aspects, including increased pulmonary and cardiovascular risk. One drawback of smoking is the smoke — cannabis smoke contains harmful irritants and carcinogens. Furthermore, smoking cannabis may be associated with a decrease in the respiratory system’s immune response and an increase in the incidence of respiratory infections. In addition, smoking cannabis, especially by people with a history of cardiovascular or cerebrovascular disease, may be associated with greater risk, including the triggering of a stroke or cardiac ischemia (a condition in which the delivery of blood and oxygen to the heart muscle is diminished).
The psychoactive and physiological effects of orally consumed cannabis typically appear approximately 90 minutes after ingestion, reach their maximum after two to three hours and last for about four to twelve hours. However, there is a heterogeneous response to oral cannabis consumption and some individuals may not appreciate the peak effect until six hours after consumption. The amount of cannabis in edibles may not be consistent throughout a single baked product (a cookie, for example) or across a batch of baked products. As a result, it is difficult to estimate the amount of cannabis contained in each portion of the edible product.
Inhalation and oral intake not only have different rates of absorption and different timing of effects, but the different modes of administration also have different bioavailability, meaning the amount of cannabinoids that is actually absorbed into your body and has an effect.
Will cannabis usage during the week before surgery help or hurt me?
Cannabis use can potentially impact your operative course as well as your recovery period. Here are a few examples of the ways in which it may impact your surgical experience:
- Cannabis use around the time of surgery may increase the intensity of post-operative perceived pain.
- Cannabis impacts the cardiovascular system, including heart rate and heart rhythm, blood pressure and demand on the heart.
- Cannabis may alter blood coagulation. According to literature reviews, the use of cannabis is associated with an increased risk of thromboembolism (blood clots within the vascular system). However, there is evidence that cannabinoids have an anticoagulant effect, as well. In addition, some components of cannabis (including THC and CBD) interact with anticoagulant medications such as warfarin (Coumadin) and make the likelihood of bleeding even greater. Also, the synthetic cannabis compounds, (including “Spice” and “K2”) may cause persistent bleeding.
- Cannabis may increase your anesthetic drug requirements. According to a study evaluating the sedation requirements of Colorado patients undergoing an endoscopic procedure, on average, patients who use cannabis require more fentanyl (an opioid), and more sedative agents to be adequately prepared for an endoscopic procedure compared to patients who do not use cannabis.
- Smoking (as opposed to vaporizing) cannabis can lead to airway irritation and increased airway reactivity.
A pamphlet at the dispensary mentioned the human endocannabinoid system. What is that and how does my cannabis use impact it?
The endocannabinoid system (ECS) is a messaging system present throughout the human body. The ECS plays a critical role in the nervous system and regulates multiple physiological processes, including appetite, digestion, mood, motor control/coordination, sleep and other processes. The ECS also influences the immune system, cardiovascular function, sensory integration/pain perception, tumor surveillance, fertility, bone physiology, the endocrine system, neural development, and many other processes.
The endocannabinoid system is comprised of three main components: endocannabinoids (the chemical messengers), receptors (the structures to which the endocannabinoids bind) and regulatory enzymes (the chemicals responsible for the manufacturing and breakdown of the endocannabinoids).
The ECS was only discovered within the last few decades and was referred to as the endocannabinoid system because compounds derived from the cannabis plant interact with the components of this messaging system. For example, THC binds to the receptors of the endocannabinoid system and alters the activity of the ECS to effect change, including causing a “high”.
The content in this article is for informational purposes only. The content is not intended to be a substitute for medical advice, diagnosis, or treatment from a qualified healthcare provider, and does not constitute medical or other professional advice.
Meredith Fisher-Corn, MD is a board-certified physician specializing in anesthesiology, perioperative and pain medicine. She received a Bachelor of Science in biomedical engineering from Duke University School of Engineering and a Medical Degree from the Mount Sinai School of Medicine. Following an anesthesiology residency and fellowship at Brigham and Women’s Hospital, Harvard Medical School, she was an attending anesthesiologist at Women and Infants Hospital, Brown University Medical School. Since 2009, Dr. Fisher-Corn has served as Editor-in-Chief of a continuing medical education website, TheAnswerPage.com.
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