Whether for medicinal purposes, recreational enjoyment, or both, some patients regularly use marijuana, and it’s important for physicians to offer honest, evidence-based advice about minimizing harm. Here’s what you can tell patients who don’t plan to stop but may be willing to adjust their habits.

 

Consumption risks

 

Marijuana poses health risks that should be weighed and considered as with any other medication or lifestyle choice. Although marijuana has gained somewhat of a natural health halo, the risks can still be significant in some patient populations.

Any use of street drugs should be discouraged due to the potential lack of control around dosage and quality. 

 

However, if your patients are purchasing marijuana products from a regulated retailer or using a prescription product, they can mitigate some health risks with low-dose edibles.

Smoking and vaping are harmful to the lungs. While vaping has been touted as a lower-risk method than combustible smoking, there’s some controversy over whether this theory holds water, given recent outbreaks of severe respiratory illnesses associated with vaping, as noted in an article in the Canadian Journal of Public Health.

Chaiton M, Kundu A, Rueda S, et al. Are vaporizers a lower-risk alternative to smoking cannabis?. Can J Public Health. 2022;113(2):293–296.

 

 

People with a history of smoking or vaping marijuana should be advised that the onset of effect will be different with edibles.

Cannabis: Inhaling vs Ingesting. Canadian Centre on Substance Use and Addiction.

The effects from inhalation are quicker, beginning within seconds and lasting about 6 hours. By contrast, ingesting marijuana (by eating or drinking) will delay and intensify the effects of THC. When drinking or eating marijuana-laced products, it can take 30 minutes to 2 hours to feel the effects, and they last longer (up to 12 hours).

 

However, ingestion requires the conversion of THC by the liver, which may be a consideration for patients with liver damage or alcohol use.

 

Cardiovascular effects

 

Widespread concerns about heart health have led experts to speculate about the impact of cannabis on cardiovascular events and risk factors. Unfortunately, there’s not enough long-term data to arrive at strong conclusions. 

A scientific statement from the American Heart Association (AHA) notes the following:

Page RL II, Allen LA, Kloner RA, et al. Medical marijuana, recreational cannabis, and cardiovascular health: a scientific statement from the American Heart Association. Circulation. 2020;142(10):e131–e152.

 

• THC increases heart rate, myocardial oxygen demand, supine blood pressure, and platelet activation and is associated with endothelial dysfunction and oxidative stress. 

• CBD may reduce heart rate and blood pressure, improve vasodilation in endothelial dysfunction, and reduce inflammation and vascular hyper-permeability in diabetic models.

• Smoking and inhaling cannabis (regardless of THC content) increases blood carboxyhemoglobin concentrations 5-fold and tar concentrations 3-fold when compared with smoking cigarettes.

The AHA notes that “carbon monoxide intoxication, which varies depending on the mode of administration, depth of inspiration, and length of breath holding, has been associated with endothelial dysfunction, increased oxidation of lipoproteins, and impaired oxygen binding, as well as various cardiac clinical presentations such as cardiomyopathy, angina, acute myocardial infarction (AMI), arrhythmia, cardiac failure, pulmonary edema, cardiogenic shock, and sudden death.”

 

Mental health precautions

 

 

Patients with a history of mental illness or substance use disorder should avoid marijuana. These mental health risks may be more detrimental to the developing adolescent brain, so access should be strictly limited and discouraged before adulthood.

If your patients are using marijuana as a substitute for mental health counseling or depression treatment, it’s important to guide them on a better path. You can start the conversation by explaining that you work with other patients who use marijuana to help manage their symptoms. Ask in a non-judgmental way if they have tried marijuana, supplements, or alternative medicines to address their mental or physical health issues.

Once your patients are willing to discuss the topic, you can be open about the risks. When appropriate, seeking the support of mental health specialists can help get your patients the care they deserve.

 

Contraindications, alternatives, and risk reduction

 

Despite the positive effects of marijuana for certain conditions, it’s not appropriate or beneficial for everyone. Obvious comorbidities (like COPD in a marijuana smoker) must be addressed either by recommending a less harmful usage method or an alternative therapy.

Encouraging your patients to explore new options can help reduce their reliance on marijuana.

For some people, marijuana use is a social ritual. As a result, standard hygiene practices aren’t always strictly followed, putting patients at risk for respiratory infections. Studies show that, during the COVID-19 pandemic, paraphernalia sharing decreased, but people may become more lax about these precautions with time.

Assaf RD, Javanbakht M, Gorbach PM, et al. Puff, Puff, Don’t Pass: harm reduction for cannabis use during a viral respiratory pandemic. Harm Reduct J. 2023;20(1):23.

In particular, individuals with autoimmune conditions, cancer, and compromised immune systems should be reminded about the importance of not sharing devices to smoke or vape marijuana.