Safety & Risks
Can CBD interact with your medications?
TL;DR — What the Evidence Shows
CBD affects liver enzymes that process many common medications. The Arthritis Foundation and ACP both advise discussing CBD with a doctor before use, especially for people taking blood thinners, statins, or blood pressure medications.
Why does CBD interact with medications?
Your liver uses special proteins called enzymes to break down the medications you take. When an enzyme breaks down a drug, it removes the drug from your bloodstream. This is how your body controls how much of a drug is active at any given time.
CBD blocks several of these enzymes. The most important one, called CYP3A4, is responsible for breaking down about half of all prescription drugs. CBD also blocks at least five other enzymes and transport proteins that process medications.
When CBD blocks these enzymes, the medications they normally process build up in your body. Higher drug levels can cause side effects that would not normally occur at your prescribed dose. In some cases, this buildup can be dangerous.
In total, CBD affects enzymes that process about 60 out of 100 prescription drugs. Source: (Nasrin 2021)
Which medications interact with CBD?
This table shows the most important medication interactions. If your medication is not listed, that does not mean it is safe to combine with CBD — CBD affects enzymes that process about 60 out of 100 prescription drugs.
| Drug class | Risk level | What happens | Key data point |
|---|---|---|---|
| Warfarin / blood thinners (Coumadin) | HIGH RISK | CBD slows the breakdown of warfarin, causing blood thinner levels to rise sharply. Bleeding that is hard to stop can result. | INR rose from 2.2 to 6.9 in one documented case. INR increased in 6 of 7 published case reports. |
| Statins (Lipitor, Zocor) | HIGH RISK | CBD can double or triple statin blood levels. Higher statin levels raise the risk of serious muscle damage (myopathy). | In severe cases, muscle breakdown (rhabdomyolysis) can damage the kidneys. Risk is mechanistically established for atorvastatin and simvastatin. |
| Blood pressure medications (Norvasc, Cardizem) | MODERATE RISK | CBD can lower blood pressure on its own. Combined with blood pressure drugs, this may cause excessive drops in blood pressure. | Dizziness, lightheadedness, and fainting can result. Fall risk is especially dangerous for older adults. |
| immunosuppressants (Prograf, Rapamune) | HIGH RISK | CBD blocks both the enzyme and transport protein that remove these drugs. Drug levels can triple. | One clinical trial participant showed approximately 3-fold increase in tacrolimus levels. Too much immunosuppressants can cause organ damage. |
| SSRIs (antidepressants) (Zoloft, Celexa, Lexapro) | MODERATE RISK | CBD slows the breakdown of these medications, causing levels to rise. | A 78-year-old on sertraline for 20 years developed severely low sodium and confusion after starting CBD. |
| Anti-seizure medications (valproate, clobazam) | HIGH RISK | CBD combined with certain anti-seizure drugs dramatically increases liver enzyme elevations. | 21 to 30 out of 100 patients on valproate plus CBD had elevated liver enzymes in clinical trials. |
| Taking 3+ daily prescriptions | HIGH RISK | Each additional medication increases the chance of an unpredictable interaction with CBD. | Adults over 65 take an average of 5 or more prescription medications daily. The combined interaction landscape is unpredictable. |
Sources: (Grayson 2017) (Smythe 2023) (Leino 2019) (Nasrin 2021) (Epidiolex PI 2025)
Should you be concerned?
This flowchart summarizes what the cited research says about interaction risk levels.
Important
This is not medical advice. It is a simplified guide to help you assess whether you need to discuss CBD with your doctor. When in doubt, the cited sources recommend consulting a healthcare provider.
Step 1: Do you take any prescription medications?
Step 2: Do you take blood thinners, statins, or immunosuppressants?
Step 3: High risk identified.
Published case reports document serious, potentially life-threatening interactions with these medications. Medical organizations classify this as high risk.
Based on cited research — not personalized medical advice.
Step 4: Do you take 3 or more daily medications?
Step 5: Lower interaction risk.
Lower interaction risk based on available data. CBD still affects liver enzymes that process many drugs.
Based on cited research — not personalized medical advice.
The 44% problem
About 44 out of 100 older adults who use cannabis products have not discussed it with a healthcare provider. This means nearly half of older users are taking a substance that interacts with common medications without their doctor's knowledge.
Doctors cannot monitor for interactions they do not know about.
Source: (U Michigan Poll 2024)
Medical organizations advise against unsupervised CBD use with these medications:
- Warfarin or other blood thinners
- Statins at any dose
- Immunosuppressants (tacrolimus, cyclosporine)
- 3 or more prescription medications daily
Based on cited sources. This is not personalized medical advice — discuss with your healthcare provider.
No one has studied CBD in people over 55
All major CBD clinical trials excluded adults over 55. The interaction risks listed on this page are based on studies of younger people. Older adults typically have slower liver processing, which could increase drug buildup and make interactions more severe.
Questions to ask your doctor about CBD
These questions can help start a conversation with your healthcare provider about CBD and your medications.
Questions to ask your doctor about CBD
Key sources cited on this page
Page last reviewed: March 2026 · Authored by Claude (Anthropic AI) · Research methodology