While searching for articles in several journals of surgery, I found an interesting and unexpected (for me) article about marijuana and surgery. Chetna Bakshi, a general surgery resident in New York, published a review about the impact of cannabis on surgical patients in The American Journal of Surgery. In fact, the use of medicinal cannabis is becoming worldwide accepted due to its effects on the human body. According to the authors, these effects can be of major importance on surgical patients and surgeons must be aware of them in a near future.
Cannabis and other cannabinoids can have effects on hunger, pain, nausea, vomiting, intestinal motility and inflammation. Why? Its active components tetrahydrocannabinol (THC) and cannabidiol (CBD) appear to be the responsible substances. In fact, the human body has two types of G-couple cannabinoid receptors (CB1 and CB2) which can be found throughout the body, mainly in brain and gastrointestinal tissues.
In murine colitis models a CB1 upregulation was found, and inflammation reduction was noted with cannabinoids use. According to several works, cannabinoids can have a positive effect as anti-inflammatory drug in Crohn’s disease, ulcerative colitis and rheumatoid pathologies (including rheumatoid arthritis). Cannabinoids inhibit the excitatory neurotransmitter release in gastrointestinal tract, slowing down the gut motility. Slowing gastrointestinal motility can be an important effect of cannabinoids in short gut syndrome and irritable bowel syndrome with diarrhea. In cases of total colectomy with ileal pouch presenting with diarrhea or extremely soft stools, cannabinoids can probably be of good help due to both anti-inflammatory and slowing gastrointestinal motility effects, I think. Additionally, THC compounds have been shown to decrease gastric acid production and having a gastro-protective effect. Cannabinoids can be used to treat chronic ulcer disease and gastrinomas, and can protect against ulcer formation following partial gastrectomy with gastrojejunal anastomosis.
Cannabis has anti-inflammatory properties and slows gut motility.
Cannabinoids use increase appetite and stimulate feeding while activating the CB1 receptors. These effects can be explored in AIDS- or cancer-related cachexia. On the contrary, the use of antagonists will decrease appetite, decrease eating and decrease body mass. One effect that is well known is reducing nausea and vomiting. According to Chetna Bakshi a recent Cochrane review concluded that cannabinoids were useful in refractory chemotherapy-related nausea and vomiting. How about in post-operative nausea and vomiting? Some authors say “yes”, others say “more studies are needed”. Pain! This is the most feared symptom and the main responsible for seeking doctor consultation. The use of cannabinoids can reduce chronic pain and can potentiate the effects of opioid drugs, leading to a decrease use of this kind of prescription.
Cannabinoids can increase apettite and treat nausea and vomiting.
There are cannabis species with higher concentrations of THC and species with higher concentrations of CBD. The first has more psychoactive properties than the last one. When smoked, cannabis will have detectable plasma concentrations within minutes. If oral intake is chosen, effects will be noted within 30-90 minutes, and will last 4-12 h. Some drugs approved in United States of America and in Europe are now available. They are synthetic forms of THC with several applications. In the USA you can find dronabinol and nabilone to treat chemotherapy-related nausea/vomiting and AIDS-related loos of appetite. Nabiximols was approved in the UK to treat chronic pain and spasticity in multiple sclerosis. As the authors state cannabinoids can increase appetite, which leads to the idea that antagonists can decrease appetite and promote weight loss. In fact, this idea was already explored, with the approval of a CB1-antagonist presented as an anti-obesity drug. However, it was a short living drug. Due to depression and suicidal ideation the medication was removed from the market.
So… I believe you are thinking that if a patient uses recreational marijuana, he will experience the same effects. Do you think so? Did you take this idea from the text above? Are you thinking in smoking it before surgery? Are you going to smoke pot because you have a chronic pain? Not so fast. Recreational marijuana has different THC and CBD concentrations, and will have negative impact in anesthesia and cardiopulmonary complications.
Do not forget that recreational marijuana is not medication!
Although cannabinoids have notable effects in gastrointestinal tract, more studies are needed to understand their effects on surgical patient and advise their use in different settings. Do you have experience in using such products? Personally, I do not, not even recreational marijuana. I will wait for the next studies before I… it doesn’t matter.
Link to PubMed:
Dr. Carlos Eduardo Costa Almeida
General Surgeon