Does CBD change the levels of immunosuppressant medicines?

Medicines and the importance of their interactions

From peer-reviewed publications and drug labels: the warnings, most important first. The same warnings also appear in the interaction checker. A medicine that is not listed can still interact with CBD.

Detailed pages: Everolimus and sirolimus and CBD · Tacrolimus and CBD

How does the interaction happen?

Tacrolimus, everolimus, sirolimus and cyclosporine are broken down in the intestinal wall and the liver mostly by the CYP3A4 enzyme; in the intestine they are also carried by P-gp (P-glycoprotein: a transporter that pumps the medicine back out of intestinal cells). A substance that slows these pathways can cause more of a medicine taken by mouth to pass into the blood and raise its level. (Everolimus (Zortress) prescribing information §7.1, Sirolimus tablets prescribing information §7, Cyclosporine (Neoral) prescribing information, PMID 39601108)

Approved CBD did not change the blood level of midazolam, which is broken down by CYP3A4. Yet in drug-level studies, the peak level and the total amount in the blood (AUC) of everolimus and tacrolimus rose, while the rate at which they leave the body (half-life) did not change. The European product information attributes this to CBD slowing P-gp in the intestine and writes that, for the same reason, the levels of sirolimus and tacrolimus taken by mouth may also rise. The authors of the tacrolimus study state that it is not yet known whether intestinal CYP3A4, CYP3A5 or P-gp plays the role. (EMA Epidyolex prescribing information 4.5 and 5.2, FDA Epidiolex label §7.2 and §12.3 (05/2026), PMID 37132402, PMID 39601108)

Mycophenolate is affected through a different pathway. In the body it is converted into its active form, mycophenolic acid; mycophenolic acid is then largely made inactive by a process called glucuronidation, especially by the UGT1A9 enzyme. CBD slows this enzyme. The product information recommends considering a dose reduction for such medicines, where even small changes in level can lead to serious side effects. (EMA Epidyolex prescribing information 4.5, FDA Epidiolex label §7.2 and §12.3 (05/2026), Mycophenolate mofetil (CellCept) prescribing information §7.1 and §12.3)

There are very few human data with cyclosporine. In the laboratory, CBD clearly slowed the breakdown of cyclosporine in human liver cell fractions; however, in a small patient study, cyclosporine levels stayed stable. In addition, the drug-level studies were done with high doses of approved CBD and in healthy volunteers; the size of the effect at the lower doses of nonprescription products is not known. (PMID 8730919, PMID 29579828, PMID 39601108)

What do studies and official drug information say?

Each finding shows the type of evidence it rests on. A case report describes a single patient; it does not prove cause and effect.

1. Drug-level study

   Tacrolimus: level rose about 3-fold in a drug-level study (2025)

   In 12 healthy volunteers who used approved CBD for 14 days, the total amount in the blood (AUC) of a single dose of tacrolimus rose 3.1-fold and its peak level 4.2-fold. In a patient who had earlier taken very high doses of pure CBD for epilepsy (2000–2900 mg a day), tacrolimus levels had also been reported to rise about 3-fold. Details are on the tacrolimus page.

   Source: PMID 39601108, PMID 31012522

2. Drug-level study

   Everolimus: level rose about 2.5-fold in a drug-level study (2023)

   In healthy volunteers using approved CBD (12.5 mg/kg twice a day), the peak level and the total amount in the blood of a single dose of everolimus rose about 2.5-fold. This finding appears in the US and European product information for approved CBD. Details are on the everolimus and sirolimus page.

   Source: PMID 37132402, FDA Epidiolex label §7.2 and §12.3 (05/2026), EMA Epidyolex prescribing information 4.5

3. Case series

   Everolimus and sirolimus: levels rose in 25 patients with tuberous sclerosis (2020)

   In 76% of 25 patients who added CBD while taking everolimus (18 patients) or sirolimus (7 patients) for tuberous sclerosis complex (TSC), the drug level rose clearly; in some patients it doubled or tripled. Side effects were seen in 40% of patients, most often diarrhea; there were no severe side effects.

   Source: PMID 31924480

4. Official drug information

   The product information for tacrolimus, sirolimus and everolimus names CBD

   The US product information for tacrolimus (08/2023), sirolimus and everolimus used in transplantation recommends close monitoring of drug levels and of side effects suggesting toxicity when used with CBD, and lowering the dose if needed. The product information for everolimus used in cancer and TSC recommends a dose reduction and level measurement with approved CBD; it states that the effect of other CBD products is not known. The product information for approved CBD also writes that the levels of sirolimus and tacrolimus taken by mouth may rise.

   Source: Tacrolimus prescribing information §5.17 and §7.3, Sirolimus tablets prescribing information §5.21 and §7.5, Everolimus (Zortress) prescribing information §5.22 and §7.1, Everolimus (Afinitor) prescribing information §2.11 and §7.1, FDA Epidiolex label §7.2 (05/2026), EMA Epidyolex prescribing information 4.5

5. Drug-level study

   Mycophenolate: mycophenolic acid rose by about a third

   When a single dose of mycophenolate mofetil was taken with approved CBD (7.5 mg/kg twice a day), the total amount of mycophenolic acid in the blood (AUC) rose by 35% and its peak level by 16%. At a higher CBD dose (12.5 mg/kg twice a day), the rise in AUC was calculated to be 58%. The product information recommends considering a dose reduction for such medicines; the doctor adjusts the dose.

   Source: EMA Epidyolex prescribing information 4.5, FDA Epidiolex label §7.2 and §12.3 (05/2026)

6. Case series

   Cyclosporine: level stayed stable in 7 kidney transplant patients (2018)

   In a study following 7 kidney transplant patients who took CBD for pain for 3 weeks (increased from 50 mg to 150 mg twice a day), drug levels stayed stable in those taking cyclosporine. In those taking tacrolimus, levels varied: in two patients the tacrolimus dose was lowered (in one, the level had also been high before CBD), and in one patient the level fell and returned to normal a week later. The number of patients is very small and the follow-up short.

   Source: PMID 29579828

7. Case report

   Cyclosporine and mycophenolate: an interaction in a transplant patient (2024)

   A drug-level interaction between CBD and cyclosporine and mycophenolate mofetil was reported in a kidney transplant patient. The paper's abstract does not give the direction or size of the change; the authors recommend monitoring drug levels to prevent drug toxicity or the medicine becoming ineffective.

   Source: PMID 38212169

8. Case report

   Tacrolimus also rose with cannabis containing THC (2016, 2019)

   In a 67-year-old man who had had a bone marrow transplant, after using an edible cannabis product containing THC, his tacrolimus level rose far above the target range (8–12 ng/mL), to 45.8 ng/mL, and he was admitted to intensive care; he was also taking an antifungal medicine that can raise tacrolimus levels. Tacrolimus toxicity was also reported in another transplant patient using THC-dominant cannabis lozenges.

   Source: PMID 27595035, PMID 30819507, PMID 38868665

9. Systematic review

   Systematic review: tacrolimus and sirolimus among the most frequently reported (2024)

   In a systematic review of 31 publications reporting cannabinoid interactions with narrow-range medicines, warfarin, valproate, tacrolimus and sirolimus stood out as the most frequently reported medicines and those that may carry the greatest risk for patients. In more than half of the publications, doctors found the medicine's blood level to be unexpectedly different.

   Source: PMID 38868665

What is monitored?

• Drug level: if you take tacrolimus, everolimus, sirolimus or cyclosporine, the medicine's blood level (usually in blood taken just before the next dose) may be measured more often when starting CBD, when changing the amount of CBD, and when stopping CBD. Your transplant team or the doctor who prescribed the medicine decides when it is measured. (Tacrolimus prescribing information §2.6 and §7.3, Everolimus (Afinitor) prescribing information §2.8, Sirolimus tablets prescribing information §7.5, FDA Epidiolex label §7.2 (05/2026))
• Kidney function: tacrolimus and cyclosporine can harm the kidneys, and this risk rises when their levels go up; your doctor monitors your kidneys with blood tests such as creatinine. Approved CBD itself can also raise creatinine by about 10% in the first two weeks without changing the kidneys' filtration rate; it is important that your doctor knows you use CBD when interpreting the results. (Tacrolimus prescribing information §5.5, Cyclosporine (Neoral) prescribing information, FDA Epidiolex label §6.1 and §12.2 (05/2026), EMA Epidyolex prescribing information 4.8)
• Signs of side effects: with tacrolimus, headache, shaking, numbness or tingling, confusion, changes in behavior or vision; with everolimus and sirolimus, mouth sores, diarrhea, signs of infection such as fever and chills, a new or worsening cough and shortness of breath. If you notice any such sign, tell your doctor right away. (Tacrolimus patient information, Everolimus (Afinitor) patient information, PMID 31924480)
• What is in the product: rises in tacrolimus levels have also been reported with products containing THC; in nonprescription CBD products, the amount of CBD on the label may not be accurate and the product may contain THC. Find out the amount of CBD and THC in the product you use from its label and its certificate of analysis. (PMID 27595035, NIH NCCIH) How to read the label and certificate of analysis

Frequently asked questions

References

Last reviewed: October 27, 2026. On this date, each source was opened and checked against the related sentence.