Tacrolimus and Felodipine: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Tacrolimus
Felodipine
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Increased tacrolimus exposure
Interaction Deep Dive
Concomitant use of tacrolimus with calcium channel blocking agents (eg, felodipine) may increase tacrolimus blood concentrations and require dosage reduction of tacrolimus1. Tacrolimus, an immunosuppressant agent, is principally metabolized by the cytochrome CYP3A hepatic enzyme system 1. Felodipine is also thought to be metabolized by CYP3A isoenzymes. Concomitant use of two or more drugs cleared by the same P450 metabolic pathway can result in competitive inhibition of metabolism. Felodipine increased tacrolimus trough level by 3-fold and dose-adjusted AUC by 2-fold in one case report 2.
Why it happens (mechanism)
Reduced tacrolimus metabolism
Literature reports
1 report — tap to read
a) Coadministration of felodipine with tacrolimus significantly increased tacrolimus bioavailability, as described in a case report. A 13 year-old boy receiving tacrolimus 4 mg twice daily for renal transplantation was started on felodipine 2.5 mg per day due to elevated blood pressure that developed on postoperative day 6. In addition to tacrolimus and felodipine, he was also receiving prednisolone, mycophenolate, ganciclovir, trimethoprim-cotrimoxazole, and fluconazole. Baseline tacrolimus trough levels at this time were between 10.6 and 20 ng/mL. Approximately 1 to 2 weeks after starting felodipine, his tacrolimus trough levels increased to greater than 30 ng/mL. His tacrolimus dose was then reduced over a one week period to 0.5 mg twice daily in order to maintain target tacrolimus trough levels. Three months after transplantation, fluconazole was discontinued, requiring a dosage increase of tacrolimus (1.5 mg twice daily) to maintain target trough levels. Eight months after transplantation, the boy's blood pressure normalized and felodipine was stopped. One week after discontinuation of felodipine, tacrolimus levels once again dropped (5.1 ng/mL), requiring another dosage increase (2.5 mg twice daily). One month after discontinuation of felodipine, tacrolimus levels decreased again (5.5 ng/mL). The tacrolimus dose was increased again (3 mg twice daily) and the patient remained stable on this final dose 2.
Common questions
Can I take Tacrolimus and Felodipine together?
Increased tacrolimus exposure Always confirm with your pharmacist or prescriber before making any change.
How serious is the Tacrolimus and Felodipine interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Tacrolimus or Felodipine need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (2)
- Product Information: PROGRAF(R) oral capsules, oral granules for suspension, intravenous injection, tacrolimus oral capsules, oral granules for suspension, intravenous injection. Astellas Pharma US Inc (per FDA), Northbrook, IL, 2022. DailyMed
- Butani L, Berg G, & Makker SP: Effect of felodipine on tacrolimus pharmacokinetics in a renal transplant recipient (letter). Transplantation 2002; 73(1):159-160. PubMed
Keep reading about Tacrolimus
Keep reading about Felodipine
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