The short answer
CBD can substantially raise oral tacrolimus exposure. Tell your transplant team before starting, stopping or changing a CBD product. They may need closer blood-level monitoring and a tacrolimus dose adjustment.
What this answer covers
The strongest study used prescription EPIDIOLEX and oral PROGRAF. Its numerical result cannot be assumed for a low-dose gummy, a different oil, an inhaled product or a topical preparation.
- Supplement or preparation
- Cannabidiol
- Medication ingredient
- tacrolimus
How large was the measured effect?
In 12 healthy adults, total tacrolimus exposure was about three times higher with CBD, and the peak was about four times higher. Researchers used prescription CBD, starting at 2.5 mg/kg twice daily for three days and then 5 mg/kg twice daily for eleven days, before a single 5 mg tacrolimus dose.
Does every CBD dose have the same effect?
No fixed multiplier applies to every product. A small kidney-transplant series using a different, lower CBD regimen found variable tacrolimus levels, including pre-existing high values and one temporary fall. That uncertainty does not cancel the controlled trial or establish a safe retail CBD dose.
What harm is the monitoring intended to prevent?
Tacrolimus exposure that is too high can increase toxicity, including kidney and nervous-system problems. The CBD trial measured drug levels in healthy people and reported no serious adverse events. It was too small and short to establish long-term safety or quantify added infection risk in transplant recipients.
Can I manage this by separating doses?
A reliable interval that prevents the interaction has not been established. The PROGRAF label instead calls for close blood-level and toxicity monitoring, with a dose reduction if needed. Your clinician should make that adjustment; reducing tacrolimus yourself could leave too little protection against rejection.
What information does the team need?
Provide the product name, CBD amount per dose, frequency and any recent changes. Include nonprescription oils and gummies when discussing supplements. If CBD is prescribed for seizures, coordinate any change with both prescribers so that its treatment and tacrolimus monitoring remain organized.
Evidence and practical considerations
Absorption & effectiveness
Pharmaceutical oral CBD increased single-dose oral tacrolimus exposure in a controlled healthy-adult study.
- Exact scope
- EPIDIOLEX titrated over fourteen days to 5 mg/kg twice daily; retail and nonoral products unquantified. with Tacrolimus, exact RxCUI 42316, inventory name tacrolimus, TTY IN. Oral systemic tacrolimus only. The US PROGRAF label describes tacrolimus capsules and anhydrous-equivalent strength; the UK capsule SmPC section 2 explicitly states tacrolimus as monohydrate. This bridges labeled monohydrate capsules to the IN, without merging different release formulations or transferring exposure results to topical or intravenous tacrolimus. No cyclosporine or other immunosuppressant evidence is substituted for tacrolimus evidence.
- Medication form and route
- oral
What remains uncertain
- Small interim healthy-volunteer study; transplant series variable and uncontrolled.
Read the supporting source summaries
Source 1: original human clinical study
ascpt.onlinelibrary.wiley.com · Source check Sep 10, 2026
Population: Twelve healthy adults with evaluable paired pharmacokinetics; 15 entered the safety cohort.
Tacrolimus total exposure increased 3.1-fold and peak concentration 4.2-fold. No change in half-life was detected. No serious adverse events or deaths were reported.
How this applies: Direct oral tacrolimus-CBD evidence for the studied pharmaceutical formulation and regimen. Supports clinician-directed monitoring and adjustment, not applying the fold change to every CBD product.
Small fixed-sequence interim study of healthy adults and single tacrolimus doses. It did not measure transplant infection, rejection or long-term kidney outcomes. Does not establish a safe low CBD dose or equivalence of retail products.
Source 2: original human clinical study
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: Seven kidney transplant recipients, mean age 64.5 years, on different immunosuppressive regimens.
Tacrolimus levels varied. Two patients required dose reductions; one already had high levels before CBD. Another had a transient low level. No severe adverse effects were reported during follow-up.
How this applies: Direct but weak clinical context showing variability at a different dose, rather than a reproducible fixed increase in all users.
Uncontrolled small series with pre-existing abnormalities, changing doses and short follow-up. Not all seven received tacrolimus. Product details are unavailable in the abstract. Cyclosporine observations are not used as tacrolimus evidence.
Research assessment: · Open full citations ↗
Timing & monitoring
CBD use with oral tacrolimus warrants close clinician-directed monitoring and possible dose reduction; spacing has not been validated.
- Exact scope
- Oral CBD, including product and dose changes. with Tacrolimus, exact RxCUI 42316, inventory name tacrolimus, TTY IN. Oral systemic tacrolimus only. The US PROGRAF label describes tacrolimus capsules and anhydrous-equivalent strength; the UK capsule SmPC section 2 explicitly states tacrolimus as monohydrate. This bridges labeled monohydrate capsules to the IN, without merging different release formulations or transferring exposure results to topical or intravenous tacrolimus. No cyclosporine or other immunosuppressant evidence is substituted for tacrolimus evidence.
- Medication form and route
- oral
What remains uncertain
- No universal dose reduction or safe CBD threshold established.
Read the supporting source summaries
Source 1: regulatory prescribing information
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: Patients receiving systemic tacrolimus for transplant immunosuppression; oral capsules and granules discussed separately from injection.
Requires drug-level monitoring and individualized dosing. Warns of nephrotoxicity, infections, neurotoxicity, QT prolongation and hyperkalemia. Avoid grapefruit and juice; CBD needs close monitoring and possible dose reduction.
How this applies: Medication-specific safety and monitoring context. Additional supplement-specific findings and explicit formulation boundaries are required.
Label warnings do not quantify the added clinical-event risk from each supplement. The oral products are not freely interchangeable; topical use is outside these data.
Source 2: original human clinical study
ascpt.onlinelibrary.wiley.com · Source check Sep 10, 2026
Population: Twelve healthy adults with evaluable paired pharmacokinetics; 15 entered the safety cohort.
Tacrolimus total exposure increased 3.1-fold and peak concentration 4.2-fold. No change in half-life was detected. No serious adverse events or deaths were reported.
How this applies: Direct oral tacrolimus-CBD evidence for the studied pharmaceutical formulation and regimen. Supports clinician-directed monitoring and adjustment, not applying the fold change to every CBD product.
Small fixed-sequence interim study of healthy adults and single tacrolimus doses. It did not measure transplant infection, rejection or long-term kidney outcomes. Does not establish a safe low CBD dose or equivalence of retail products.
Research assessment: · Open full citations ↗
Side effects & toxicity
Increased tacrolimus exposure creates a toxicity concern, but the CBD trial did not quantify transplant kidney injury or infection.
- Exact scope
- Oral CBD at studied doses. with Tacrolimus, exact RxCUI 42316, inventory name tacrolimus, TTY IN. Oral systemic tacrolimus only. The US PROGRAF label describes tacrolimus capsules and anhydrous-equivalent strength; the UK capsule SmPC section 2 explicitly states tacrolimus as monohydrate. This bridges labeled monohydrate capsules to the IN, without merging different release formulations or transferring exposure results to topical or intravenous tacrolimus. No cyclosporine or other immunosuppressant evidence is substituted for tacrolimus evidence.
- Medication form and route
- oral
What remains uncertain
- Potential toxicity supported by label; no serious event in small trial does not establish long-term safety.
Read the supporting source summaries
Source 1: original human clinical study
ascpt.onlinelibrary.wiley.com · Source check Sep 10, 2026
Population: Twelve healthy adults with evaluable paired pharmacokinetics; 15 entered the safety cohort.
Tacrolimus total exposure increased 3.1-fold and peak concentration 4.2-fold. No change in half-life was detected. No serious adverse events or deaths were reported.
How this applies: Direct oral tacrolimus-CBD evidence for the studied pharmaceutical formulation and regimen. Supports clinician-directed monitoring and adjustment, not applying the fold change to every CBD product.
Small fixed-sequence interim study of healthy adults and single tacrolimus doses. It did not measure transplant infection, rejection or long-term kidney outcomes. Does not establish a safe low CBD dose or equivalence of retail products.
Source 2: regulatory prescribing information
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: Patients receiving systemic tacrolimus for transplant immunosuppression; oral capsules and granules discussed separately from injection.
Requires drug-level monitoring and individualized dosing. Warns of nephrotoxicity, infections, neurotoxicity, QT prolongation and hyperkalemia. Avoid grapefruit and juice; CBD needs close monitoring and possible dose reduction.
How this applies: Medication-specific safety and monitoring context. Additional supplement-specific findings and explicit formulation boundaries are required.
Label warnings do not quantify the added clinical-event risk from each supplement. The oral products are not freely interchangeable; topical use is outside these data.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Article prepared | |
| Original evidence and current product information inspected; article distinguishes observed results, product limits and remaining uncertainty. | |
| Research summary published |
Article revision: 720d27070084f9c5
This guide brings together the evidence records used by our interaction checker. Each finding retains its own preparation limits, research date, and source summaries.
Full citations require verification. Reading this answer and the source summaries does not.
Taking other supplements or medications?
Use the checker to explore your other combinations. Ask a pharmacist to review the exact products, amounts and medical conditions in your complete list.
Open the interaction checkerInformation, not medical advice. Do not change prescribed treatment based on this guide.