Cannabis has complex heart effects: THC may increase heart attack risk while CBD may be protective
A review of drugs of abuse and heart failure found that THC can increase sympathetic tone and vascular dysfunction, potentially increasing myocardial infarction risk, while CBD shows cardioprotective properties in preclinical studies.
Quick Facts
What This Study Found
Cannabis has complex cardiovascular effects depending on consumption method, amount, and cannabinoid content. THC can increase sympathetic tone, cause vascular dysfunction, and may increase myocardial infarction risk. CBD is cardioprotective in preclinical studies and is a potential therapeutic target. The effects are complicated by the interaction between these opposing cannabinoid profiles.
Key Numbers
THC: increases sympathetic tone, causes vascular dysfunction, may increase MI risk; CBD: cardioprotective in preclinical studies; effects vary by consumption method, dose, and cannabinoid content
How They Did This
Narrative review of the cardiovascular effects of alcohol, tobacco, cannabis, and cocaine on heart failure development and outcomes.
Why This Research Matters
Heart failure patients may use cannabis, and clinicians need to understand the opposing cardiovascular effects of THC and CBD to provide appropriate guidance, especially as legal access increases.
The Bigger Picture
The opposing cardiovascular effects of THC and CBD suggest that the net cardiac risk of cannabis use depends heavily on the product's cannabinoid ratio, which varies enormously across products and is rarely known by consumers.
What This Study Doesn't Tell Us
Narrative review with limited cannabis-specific clinical trial data. Most evidence is preclinical for CBD cardioprotection. Cannabis cardiovascular research is confounded by tobacco co-use. Heart failure-specific cannabis data are sparse.
Questions This Raises
- ?Would CBD-dominant products be safe or even beneficial for heart failure patients?
- ?Should THC-dominant products carry specific cardiovascular warnings?
Trust & Context
- Key Stat:
- THC increases sympathetic tone and MI risk; CBD is cardioprotective in preclinical studies
- Evidence Grade:
- Comprehensive narrative review drawing from multiple evidence sources, but limited cannabis-specific clinical data.
- Study Age:
- Published in 2021.
- Original Title:
- Drugs of Abuse and Heart Failure.
- Published In:
- Journal of cardiac failure, 27(11), 1260-1275 (2021)
- Database ID:
- RTHC-03175
Evidence Hierarchy
Summarizes existing research on a topic.
What do these levels mean? →Frequently Asked Questions
Is cannabis bad for the heart?
It depends on the cannabinoid. THC can increase heart rate, sympathetic activation, and vascular dysfunction, potentially increasing heart attack risk. CBD appears to be cardioprotective in animal studies. The net effect depends on the product's THC-to-CBD ratio.
Can people with heart failure use cannabis?
The review suggests caution, particularly with THC-dominant products. CBD's potential cardioprotective effects are promising but based on preclinical data. Clinicians should assess cardiovascular risk when counseling patients about cannabis use.
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Cite This Study
https://rethinkthc.com/research/RTHC-03175APA
Grubb, Alex F; Greene, Stephen J; Fudim, Marat; Dewald, Tracy; Mentz, Robert J. (2021). Drugs of Abuse and Heart Failure.. Journal of cardiac failure, 27(11), 1260-1275. https://doi.org/10.1016/j.cardfail.2021.05.023
MLA
Grubb, Alex F, et al. "Drugs of Abuse and Heart Failure.." Journal of cardiac failure, 2021. https://doi.org/10.1016/j.cardfail.2021.05.023
RethinkTHC
RethinkTHC Research Database. "Drugs of Abuse and Heart Failure." RTHC-03175. Retrieved from https://rethinkthc.com/research/grubb-2021-drugs-of-abuse-and
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.