A single dose of cannabidiol reduces blood pressure in healthy volunteers in a randomized crossover study

Abstract

Background: Cannabidiol (CBD) is a nonpsychoactive phytocannabinoid used in multiple sclerosis and intractable epilepsies. Preclinical studies show CBD has numerous cardiovascular benefits, including a reduced blood pressure (BP) response to stress. The aim of this study was to investigate if CBD reduces BP in humans.

Methods: Nine healthy male volunteers were given 600 mg of CBD or placebo in a randomized, placebo-controlled, double-blind, crossover study. Cardiovascular parameters were monitored using a finometer and laser Doppler.

Results: CBD reduced resting systolic BP (-6 mmHg; P < 0.05) and stroke volume (-8 ml; P < 0.05), with increased heart rate (HR) and maintained cardiac output. Subjects who had taken CBD had lower BP (-5 mmHg; P < 0.05, especially before and after stress), increased HR (+10 bpm; P < 0.01), decreased stroke volume (-13 ml; P < 0.01), and a blunted forearm skin blood flow response to isometric exercise. In response to cold stress, subjects who had taken CBD had blunted BP (-6 mmHg; P < 0.01) and increased HR (+7 bpm; P < 0.05), with lower total peripheral resistance.

Conclusions: This data shows that acute administration of CBD reduces resting BP and the BP increase to stress in humans, associated with increased HR. These hemodynamic changes should be considered for people taking CBD. Further research is required to establish whether CBD has a role in the treatment of cardiovascular disorders.

Keywords: Therapeutics; Vascular Biology.

Conflict of interest statement

Conflict of interest: GW Pharma supplied the cannabidiol (CBD) and placebo but did not fund the study.

Figures

Figure 1. Changes in resting cardiovascular parameters after a single dose (600 mg) of cannabidiol (CBD) in healthy volunteers (n = 9).

The effects of placebo (closed square) and CBD (open square) on systolic blood pressure (SBP) (A), diastolic blood pressure (DBP) (B), mean arterial blood pressure (MAP) (C), heart rate (HR) (D), stroke volume (SV) (E), cardiac output (CO) (F), ejection time (EJT) (G), total peripheral resistance (TPR) (H), and forearm blood flow (I), measured continuously over 2 hours after drug ingestion, except for forearm blood flow. Forearm blood was measured over a time period of 2 minutes just before the start and in between the stress tests. Dotted line denotes baseline values between the stress tests. Repeated measures 2-way ANOVA; mean ± SEM (*/+/#P < 0.05, **/++/##P < 0.01 using Bonferroni’s post-hoc analysis; + and # represent significant change in any parameter over time seen with placebo and CBD, respectively; denotes overall significant difference between 2 treatments).

Figure 2. Individual systolic and diastolic blood pressure responses to all stress tests after a single dose (600 mg) of cannabidiol (CBD) or placebo in healthy volunteers (n = 9).

Green color coding shows subjectS who had a reduced (compared with placebo) blood pressure response to stress after taking CBD, and red color coding shows an increased blood pressure response to stress after taking CBD.

Figure 3. Cardiovascular response to mental stress after a single dose (600 mg) of cannabidiol (CBD) in healthy volunteers (n = 9).

The effects of placebo (closed square) and CBD (open square) on systolic blood pressure (SBP) (A), diastolic blood pressure (DBP) (B), mean arterial blood pressure (MAP) (C), heart rate (HR) (D), stroke volume (SV) (E), cardiac output (CO) (F), ejection time (EJT) (G), total peripheral resistance (TPR) (H), and forearm blood flow (I), measured continuously just before, during, and after mental arithmetic test (dotted line denotes stress test period), except for forearm blood flow. Measurements for forearm blood flow were made over a 2-minute window just before, during, and after the stress test. Repeated measures 2-way ANOVA; mean ± SEM (+ and # denote significant change in a parameter during the stress period seen with placebo and CBD, respectively). +/#P < 0.05, ++/##P < 0.01.

Figure 4. Cardiovascular parameters in response to exercise stress after a single dose (600 mg) of cannabidiol (CBD) in healthy volunteers (n = 9).

The effects of placebo (closed square) and CBD (open square) on systolic blood pressure (SBP) (A), diastolic blood pressure (DBP) (B), mean arterial blood pressure (MAP) (C), heart rate (HR) (D), stroke volume (SV) (E), cardiac output (CO) (F), ejection time (EJT) (G), total peripheral resistance (TPR) (H), and forearm blood flow (I), measured continuously just before, during, and after isometric exercise test (dotted line denotes stress test period), except for forearm blood flow. Measurements for forearm blood flow were made over a 2-minute window just before, during, and after the stress test. Repeated measures 2-way ANOVA; mean ± SEM (*/+/#P < 0.05; **/++/##P < 0.01; ***/###P < 0.001; ****/####P < 0.0001 using Bonferroni post-hoc analysis; + and # denote significant change in a parameter during the stress period seen with placebo and CBD respectively).

Figure 5. Cardiovascular response to cold stress after a single dose (600 mg) of cannabidiol (CBD) in healthy volunteers (n = 9).

The effects of placebo (closed square) and CBD (open square) on systolic blood pressure (SBP) (A), diastolic blood pressure (DBP) (B), mean arterial blood pressure (MAP) (C), heart rate (HR) (D), stroke volume (SV) (E), cardiac output (CO) (F), ejection time (EJT) (G), total peripheral resistance (TPR) (H), and forearm blood flow (I), measured continuously just before, during, and after cold pressor test (dotted line denotes stress test period), except for forearm blood flow. Measurements for forearm blood flow were made over a 2-minute window just before, during, and after the stress test. Repeated measures 2-way ANOVA; mean ± SEM (*/+/#P < 0.05, **/++P < 0.01, ***/+++P < 0.001, ****P < 0.0001 using Bonferroni post-hoc analysis; + and # denote significant change in a parameter during the stress period seen with placebo and CBD, respectively).