From the Guidelines
The use of Tetrahydrocannabinol (THC) in patients with coronary artery disease (CAD) is generally not recommended due to potential cardiovascular risks. THC can increase heart rate and raise blood pressure, potentially triggering angina in susceptible individuals, as noted in a study published in the British Journal of Anaesthesia 1. These effects typically occur within minutes of use and can last for 1-3 hours, creating additional cardiac workload that may be dangerous for CAD patients. Key concerns with THC use in CAD patients include:
- Increased heart rate by 20-50 beats per minute
- Raised blood pressure while standing
- Potential to trigger angina in susceptible individuals
- Impaired blood flow to the heart
- Association with an increased risk of heart attack in the hours following use, as suggested by the mechanisms of action of THC on the cardiovascular system 1. For patients with CAD who are considering cannabis for medical purposes, CBD-dominant products with minimal THC content would be safer alternatives, given CBD's role as a negative allosteric modulator of the cannabinoid receptor and its potential to reduce the adverse effects of THC 1. If a patient with CAD is currently using THC, they should be advised to start with very low doses, avoid smoking or vaping, and be vigilant for symptoms like chest pain, palpitations, or shortness of breath. The cardiovascular effects of THC are primarily mediated through activation of the endocannabinoid system and sympathetic nervous system stimulation, which can be particularly problematic in those with pre-existing coronary disease, highlighting the need for cautious management and monitoring 1.
From the Research
THC and Coronary Artery Disease
- The use of Tetrahydrocannabinol (THC) in patients with coronary artery disease is a topic of concern due to its potential effects on the cardiovascular system 2, 3, 4, 5.
- Studies have shown that cannabis smoking, which contains THC, can lead to an increase in heart rate and blood pressure, as well as vascular inflammation, platelet activation, and carboxyhemoglobin generation 2.
- A systematic review of 85 publications involving 541,518 human subjects found that 28 of the 33 studies highlighted an increased risk of both acute coronary syndrome and chronic cardiovascular disease from cannabis use 2.
- Case reports have also described instances of acute coronary syndrome occurring in cannabis smokers, including two illustrative cases of young adults who suffered from hypertension and acute coronary syndrome at a very young age 3.
- Another study found that cannabis use can precipitate cardiovascular emergencies, including malignant arrhythmia and acute myocardial infarction, in patients with underlying coronary artery disease 4.
- The cardiovascular consequences of marijuana use, including THC, have been reviewed, and it has been suggested that patients with coronary heart disease or those at high risk for the development of CHD should be cautioned about the potential hazards of marijuana use as a precipitant for clinical events 5.
Key Findings
- Cannabis use is associated with an increased risk of acute coronary syndrome and chronic cardiovascular disease 2.
- THC can lead to an increase in heart rate and blood pressure, as well as vascular inflammation and platelet activation 2, 5.
- Cannabis smoking can precipitate cardiovascular emergencies, including malignant arrhythmia and acute myocardial infarction, in patients with underlying coronary artery disease 3, 4.
- Patients with coronary heart disease or those at high risk for the development of CHD should be cautious about the potential hazards of marijuana use 5.