Cannabis effects on blood pressure
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Acute Cannabis Effects on Blood Pressure: Systolic and Diastolic Changes
Research shows that cannabis can have both increasing and decreasing effects on blood pressure, depending on the context and population. Acute cannabis use is often associated with a mild, dose-dependent increase in systolic blood pressure (SBP), while diastolic blood pressure (DBP) may not be significantly affected in the general population Alshaarawy2016Goyal2017Sidney2002+1 MORE. Some studies also report that cannabis can cause orthostatic hypotension, which is a drop in blood pressure when standing up, due to decreased vascular resistance Alshaarawy2016Goyal2017Sidney2002+1 MORE.
Chronic and Heavy Cannabis Use: Blood Pressure Reduction
Long-term or heavy cannabis use appears to have a modest association with lower blood pressure. Large population studies have found that lifetime heavy cannabis users tend to have slightly lower SBP and DBP compared to non-users, with the effect being more pronounced in women . In older adults with hypertension, three months of medical cannabis use was linked to a significant reduction in both 24-hour systolic and diastolic blood pressure, with the lowest blood pressure observed about three hours after cannabis administration . However, the overall differences in blood pressure between heavy users and non-users are small and may not be clinically significant for public health policy .
Blood Pressure Variability and Withdrawal Effects
Active cannabis use has been associated with increased visit-to-visit blood pressure variability (BPV), which is an important predictor of cardiovascular risk . Additionally, abrupt cessation of daily cannabis use can lead to significant increases in both systolic and diastolic blood pressure, especially in individuals who were heavy users, suggesting that withdrawal may temporarily raise cardiovascular risk .
Special Populations: Spinal Cord Injury and Blood Pressure Control
In individuals with spinal cord injury, cannabis use has been reported to improve blood pressure stability and reduce the frequency and severity of episodes of autonomic dysreflexia, a condition characterized by sudden high blood pressure . However, in rare cases, cannabis use in this context has also led to prolonged hypotension.
Mechanisms and Tolerance
The cardiovascular effects of cannabis are mediated by the autonomic nervous system and the endocannabinoid system. Tolerance to the acute blood pressure-raising effects of cannabis develops quickly with repeated use, leading to a decrease in these effects over time Sidney2002Jones2002. Chronic use may result in a slight decrease in resting blood pressure and reduced orthostatic hypotension .
Risks and Considerations
While most young, healthy users do not experience serious cardiovascular problems from cannabis, there are reports of increased risk for arrhythmias, myocardial infarction, and stroke, particularly in those with pre-existing cardiovascular disease or when cannabis is used in combination with other risk factors like cigarette smoking Goyal2017Sidney2002Jones2002. The cardiovascular safety of cannabis, especially in older adults and those with hypertension, requires further research Abuhasira2021Goyal2017.
Conclusion
Cannabis has complex effects on blood pressure, with acute use often causing mild increases in systolic blood pressure and possible orthostatic hypotension, while chronic or heavy use may be linked to small reductions in blood pressure, especially in older adults and women. Blood pressure variability may increase with active use, and withdrawal can cause significant blood pressure spikes in heavy users. The overall clinical impact of these changes is modest for most people, but individuals with cardiovascular conditions should use caution and consult healthcare providers regarding cannabis use. Further research is needed to clarify the long-term cardiovascular effects of cannabis.
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