CBD and Beta-Blockers (e.g. Concor, Bisoprolol, Atenolol, Tenormin)
David ReichUpdated:Key points at a glance:
CBD may interact with beta blockers. It can influence liver enzymes such as CYP3A4 and CYP2D6, which may affect how certain medicines are processed in the body. Bisoprolol is considered moderately sensitive to such interactions. Atenolol is mainly excreted via the kidneys and may show more additive effects. Both combinations may be associated with a further lowering of blood pressure and heart rate. If using CBD alongside beta blockers, some people choose to start with a low amount and to monitor blood pressure and pulse twice daily over a 14‑day period. In cases of dizziness, fainting, or a very slow pulse, it is advisable to stop use and seek medical advice.
Many people taking beta blockers for heart or blood pressure problems are interested in trying CBD oil. This article explains what is currently known about CBD and beta-blocker interactions (including bisoprolol and atenolol), how CBD may affect drug metabolism and blood pressure, and how to monitor yourself safely in the first 14 days if you and your doctor decide to combine them.
Quick overview: What are beta blockers?
Beta blockers are prescribed for conditions such as high blood pressure, heart rhythm disturbances and angina. They reduce the effects of stress hormones on the heart, which can lower blood pressure and heart rate and reduce strain on the heart. Examples include Concor (bisoprolol), atenolol and Tenormin (atenolol).
What is CBD?
CBD (cannabidiol) is a plant‑derived compound from hemp. Many users report a sense of relaxation and improved sleep. CBD acts via the endocannabinoid system, which is associated with processes such as sleep, mood and immune responses. More basic information can be found here: Effects of CBD in the body. Some people prefer traditional oils, others opt for highly concentrated products such as CBD concentrates – in all cases, it is advisable to start with a low amount.
How CBD may interact with beta blockers
CYP enzymes and CBD metabolism
Many prescription medicines, including some beta blockers, are broken down in the liver by enzymes known as cytochrome P450 (CYP) enzymes. CBD may inhibit certain CYP enzymes involved in drug metabolism – in particular CYP3A4, CYP2D6 and CYP2C19. Depending on the specific beta blocker, this could slow its breakdown and increase the drug level in the blood.
The relevance varies: substances with a strong CYP2D6/CYP3A4 component are potentially more sensitive, while beta blockers that are mainly eliminated renally (via the kidneys) are generally considered less susceptible. Systematic reviews describe this inhibition, but also emphasise that individual differences are substantial and that clinical data on CBD–beta blocker combinations are still limited.
CBD can inhibit liver enzymes (CYP3A4, CYP2D6, CYP2C19) that metabolise some beta blockers. This may lead to stronger or longer‑lasting effects of the medication in certain individuals.
Additive effects on blood pressure and heart rate
Aside from its effects on liver enzymes, CBD itself has been associated in some studies with a short‑term, mild lowering of blood pressure and heart rate. A small human study (JCI Insight, 2017) reported that a single dose of CBD temporarily reduced blood pressure in healthy volunteers. This result cannot be directly generalised to all individuals or to long‑term use, but it is relevant for people taking beta blockers: the blood‑pressure‑lowering and heart‑rate‑slowing effects could add up.
In practice, this may increase the likelihood of dizziness, light‑headedness or, in rare cases, fainting, particularly when starting CBD or increasing the amount.
CBD may mildly lower blood pressure and heart rate. Together with beta blockers, this can increase the risk of blood pressure that is too low, dizziness or, rarely, fainting.
If you use CBD alongside beta blockers, a cautious approach is advisable: start with a low amount, increase gradually and monitor your blood pressure and pulse closely. Further background: CBD interactions.
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CBD and different beta blockers: Why the active ingredient matters
Not all beta blockers are processed in the body in the same way. Their route of metabolism influences how likely a CBD drug interaction is and how strong it might be. The table below summarises two common examples:
| Active substance | Metabolism | Interaction potential | Note |
|---|---|---|---|
| Bisoprolol (Concor) | partly CYP3A4/2D6, partly renal | moderate | possible increase in effect; monitoring important |
| Atenolol (Tenormin) | predominantly renal | lower (PK), but PD relevant | be aware of potential for low blood pressure/slow heart rate |
CBD and bisoprolol (Concor)
Bisoprolol is partly metabolised via CYP3A4/2D6 and partly eliminated renally. Because CBD may inhibit CYP3A4 and CYP2D6, it could, in theory, reduce the breakdown of bisoprolol and increase its effect. At the same time, both CBD and bisoprolol can lower blood pressure and heart rate, so additive effects are possible.
Discuss any plans to use CBD and bisoprolol together with your doctor beforehand. If your doctor agrees, keeping a blood pressure and pulse log for the first 14 days (see monitoring plan below) can help identify any changes early.
CBD and atenolol (Tenormin)
Atenolol is predominantly excreted via the kidneys, and CYP enzymes play only a minor role in its elimination. Pharmacokinetic interactions (via liver enzymes) with CBD are therefore considered less likely. However, atenolol can still lower blood pressure and heart rate, and CBD may do the same in some people, so the combined effects on circulation remain relevant.
Here too, it is advisable to discuss CBD use with your doctor, begin with a low amount, watch out for dizziness or tiredness, and measure blood pressure and pulse regularly.
Other beta blockers may also be affected: Metoprolol (mainly CYP2D6) and propranolol (CYP2D6/CYP1A2) are often considered more sensitive to CYP inhibition. If you are using another beta blocker, medical advice is recommended, and the same cautious monitoring approach can be applied.
CBD–beta blocker interactions vary by active ingredient. Bisoprolol and some other CYP‑metabolised beta blockers may be more affected by CBD’s impact on liver enzymes than atenolol, which is mainly excreted via the kidneys. With all beta blockers, additive effects on blood pressure and heart rate remain important.
Monitoring plan: CBD and beta blockers in the first 14 days
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Before you start
Inform your doctor about your intention to try CBD. Review your current medication list with them. For 3 days before starting CBD, measure and record baseline blood pressure and pulse twice daily (morning and evening). -
Starting CBD
Start low and increase slowly. Take CBD once a day at the same time (many people choose the evening, as CBD may be associated with tiredness). Avoid sudden high doses. -
Days 1–14: regular measurements
Record blood pressure and pulse morning and evening. Note any symptoms such as dizziness, light‑headedness, unusual tiredness, blurred vision or palpitations. -
If you notice anything unusual
If you experience persistent dizziness, a systolic blood pressure clearly lower than your usual readings, or a noticeably slow pulse, pause CBD and seek medical assessment. Do not adjust prescription medicines on your own.
Before combining CBD with beta blockers, agree a plan with your doctor, record baseline readings, start CBD with a low amount, and track blood pressure, pulse and symptoms twice daily for at least 14 days.
Side effects when CBD and beta blockers are combined
When CBD and beta blockers are taken together, possible effects include dizziness, light‑headedness, tiredness, a drop in blood pressure and a slower heart rate. These symptoms are often mild and may lessen if the amount of CBD is reduced or stopped, but they should be taken seriously – especially at the beginning of the combination or after dose changes.
If you notice new or worsening symptoms, seek medical advice. More details on CBD effects and tolerability can be found here: CBD side effects.
Conclusion
CBD and beta blockers such as bisoprolol (Concor) and atenolol (Tenormin) may sometimes be used together under medical supervision, but careful monitoring is important. With bisoprolol and other CYP‑metabolised beta blockers, both pharmacokinetic interactions (via liver enzymes) and additive effects on blood pressure and heart rate are considered possible. With atenolol, interactions via liver enzymes are considered less likely, but additive effects on circulation still matter.
If you and your doctor decide to try CBD while you are taking beta blockers, start with a low amount, increase slowly, and monitor blood pressure and pulse consistently in the first 14 days. Further background can be found in our overview of CBD–medication interactions and information on CBD dosage.
Disclaimer: This article is for information purposes only and does not replace medical advice. Do not change medicines or dosages without consulting your doctor. No claims are made regarding the treatment or cure of illnesses.