Does thc raise blood pressure
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The Impact of THC on Blood Pressure: A Comprehensive Review
Introduction to THC and Blood Pressure
Delta-9-tetrahydrocannabinol (THC), the primary psychoactive component of cannabis, has complex effects on the cardiovascular system, including blood pressure (BP). Understanding these effects is crucial, especially given the increasing use of cannabis for both recreational and medicinal purposes.
Acute Effects of THC on Blood Pressure
Animal Studies on Acute THC Administration
In animal models, acute administration of THC generally results in a reduction of blood pressure. Studies have shown that in both anesthetized and conscious animals, THC significantly lowers BP. For instance, in anesthetized animals, THC reduced BP by an average of 19.7 mmHg, while in conscious animals, the reduction was 12.3 mmHg1. These effects are also observed in animal models of stress or hypertension, where THC administration led to a BP decrease of 61.37 mmHg1.
Human Studies on Acute THC Administration
In contrast to animal studies, the effects of acute THC administration on human blood pressure are less consistent. Some studies indicate that THC can cause a modest increase in heart rate (HR) without significantly affecting BP2. However, other research suggests that THC may lead to orthostatic hypotension, a condition where blood pressure drops significantly upon standing, causing dizziness and lightheadedness in some individuals5.
Chronic Effects of THC on Blood Pressure
Animal Studies on Chronic THC Administration
Chronic administration of THC in animal models has been shown to increase blood flow in large arteries and reduce BP in models of stress or hypertension. For example, chronic THC dosing resulted in a BP reduction of 22.09 mmHg in these models1. This suggests a potential therapeutic role for THC in managing hypertension over prolonged periods.
Human Studies on Chronic THC Administration
In humans, prolonged ingestion of THC has been associated with a significant slowing of heart rate and a reduction in blood pressure. This is indicative of a state of sympathetic insufficiency, where the body's sympathetic nervous system is less active6. Tolerance to the initial cardiovascular effects of THC, such as tachycardia and orthostatic hypotension, also develops with repeated exposure5.
Mechanisms Behind THC's Effects on Blood Pressure
Role of Cannabinoid Receptors
The cardiovascular effects of THC are mediated through the activation of cannabinoid receptors, primarily CB1 and CB2. These receptors play a crucial role in regulating blood pressure and heart rate. For instance, the activation of CB1 receptors by THC can lead to hypotension and bradycardia in animals7. In humans, the role of CB1 receptors is more complex, with some studies showing that blocking these receptors can attenuate the hypotensive effects of THC2.
Sympathetic and Parasympathetic Nervous System
THC's impact on the autonomic nervous system also contributes to its effects on blood pressure. Acute THC administration can increase heart rate and decrease parasympathetic activity, as measured by high-frequency heart rate variability (HF-HRV)3. Over time, however, THC appears to reduce sympathetic activity, leading to lower blood pressure and heart rate6.
Conclusion
The effects of THC on blood pressure are multifaceted and vary depending on the dosage, duration of use, and the species being studied. Acute administration of THC tends to lower blood pressure in animals but has inconsistent effects in humans, sometimes causing orthostatic hypotension. Chronic use of THC generally leads to a reduction in blood pressure and heart rate, with the development of tolerance to its initial cardiovascular effects. Understanding these dynamics is essential for assessing the potential risks and therapeutic benefits of THC, particularly for individuals with cardiovascular conditions. Further research is needed to fully elucidate the mechanisms behind THC's cardiovascular effects and to establish clear guidelines for its safe use.
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Most relevant research papers on this topic
A Systematic Review and Meta-Analysis of the In Vivo Haemodynamic Effects of Δ9-Tetrahydrocannabinol
THC has complex effects on the cardiovascular system, causing bradycardia, hypotension, and increased blood flow in animals and increasing heart rate in humans.
Meta-AnalysisThe cannabinoid CB1 receptor antagonist rimonabant attenuates the hypotensive effect of smoked marijuana in male smokers.
CB1 receptors play a role in mediating the hypotensive effects of cannabis smoking in male smokers, with rimonabant attenuating this effect.
RCTAcute effects of oral delta-9-tetrahydrocannabinol (THC) on autonomic cardiac activity and their relation to subjective and anxiogenic effects.
Oral THC increases heart rate and decreases high frequency heart rate variability in healthy adult women, with these effects affecting subjective drug experience and potentially increasing risk factors for cannabis use.
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Very Rigorous JournalThe Effect of Delta‐9‐Tetrahydrocannabinol and Cannabidiol on Blood Flow and Blood Pressure
THC and CBD separately and in combination can affect blood flow and blood pressure, with THC having a greater impact on blood flow than CBD.
Non-RCT
Rigorous JournalCardiovascular System Effects of Marijuana
Marijuana increases heart rate, slightly increases blood pressure, and occasionally produces orthostatic hypotension, with tolerance developing over time.
Highly CitedCardiovascular effects of prolonged delta‐9‐tetrahydrocannabinol ingestion
Prolonged THC ingestion leads to heart rate slowing and blood pressure lowering, suggesting a biphasic effect on the sympathetic nervous system in humans.
Non-RCTHighly CitedAt the heart of the matter: the endocannabinoid system in cardiovascular function and dysfunction.
THC and endocannabinoids have hypotensive effects and potential therapeutic potential in cardiac injury protection, metabolic cardiovascular risk factors, and atherosclerotic plaque vulnerability.
Highly CitedSynthetic cannabinoids found in "spice" products alter body temperature and cardiovascular parameters in conscious male rats.
Synthetic cannabinoids cause hypothermia in rats through cannabinoid receptors, while they increase blood pressure independently of these sites, with the hypertensive effect involving central sympathetic outflow.
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Animal StudyCardiovascular Consequences of Marijuana Use
Marijuana use may increase heart rate and blood pressure, and may trigger cardiovascular events, but current data on its association with cardiovascular disease outcomes is limited.
Literature ReviewHighly CitedDose-related effects of delta-9-THC on emotional responses to acute psychosocial stress.
A low dose of THC reduces subjective stress and increases positive mood, while higher doses may increase negative mood and impair performance in a stress test.
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