Raw research findings for this medication. Mostly single studies, not curated or confirmed robust.
Tacrolimus is an immunosuppressant: it calms the immune system by blocking calcineurin, a signal T cells need to become active. It is used after kidney, liver, heart and other transplants so the body does not reject the new organ, and as an ointment for eczema. Blood levels are checked regularly, because too little risks rejection and too much causes side effects. It is sold as Prograf, among other names.
Tacrolimus is broken down mainly by the enzymes CYP3A5 and CYP3A4. Most people of European ancestry carry two copies of CYP3A5*3, which makes no working enzyme; people with at least one working copy (*1), more common in people of African ancestry, clear tacrolimus faster and have lower blood levels from the same amount. CPIC and DPWG have published guidelines on CYP3A5 and tacrolimus. Studies have also looked at CYP3A4, at the transporter ABCB1 and at other genes, with weaker evidence.
Clinical guidelines that name a gene for Tacrolimus. They sort people into groups by the gene copies they carry.
Every published finding on gene variants and Tacrolimus. Upload your DNA file to see which of these rows apply to you.
PharmGKB weighs all studies of a variant and rates how strong the evidence is, from 1A (strongest) to 4.
CYP3A5 CYP3A5*1, CYP3A5*3, CYP3A5*6, CYP3A5*7: Level 1A · replicated. Metabolism/PK: Heart transplantation, Hematopoietic stem cell transplantation, Kidney Transplantation, Lung transplantation. 144.
CYP3A5 CYP3A5*1, CYP3A5*3, CYP3A5*6, CYP3A5*7: Level 1A · replicated. Dosage: Heart transplantation, Hematopoietic stem cell transplantation, Kidney Transplantation, Liver transplantation, Lung transplantation. 97.
CYP3A5 CYP3A5*1, CYP3A5*3: Level 1B · replicated. Metabolism/PK: Liver transplantation. 26.
CYP3A5 CYP3A5*1, CYP3A5*3: Level 1B · replicated. Metabolism/PK: Liver transplantation. 24.
Studies of how quickly the body processes this medication.
Studies of how well it worked in people carrying a variant.
Studies of how much of the drug people needed or tolerated.
Studies of side effects in people carrying a variant.
Studies that do not fall into the groups above.
Study findings and evidence levels: PharmGKB (CC BY-SA 4.0). Guidelines: CPIC and DPWG, as bundled in PharmCAT. Most studies were done mainly in people of European ancestry.
More drugs from the same category
Not a prescribing recommendation. This page is educational information about pharmacogenomic research and clinical guidelines - it is not medical or dosing advice, and not a prediction of how any medication will work for you. Never start, stop, or change a medication or dose based on it; talk to your doctor or pharmacist, who can order clinical-grade testing if appropriate.
Content updated September 2026.
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