Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
TACROLIMUS vs GENGRAF
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Tacrolimus is a calcineurin inhibitor. It binds to FK506-binding protein 12 (FKBP12), forming a complex that inhibits calcineurin phosphatase activity. This prevents dephosphorylation and nuclear translocation of nuclear factor of activated T-cells (NFAT), thereby inhibiting transcription of interleukin-2 (IL-2) and other cytokines, leading to suppressed T-cell activation and proliferation.
Calcineurin inhibitor; binds to cyclophilin, inhibits calcineurin-dependent T-cell activation, preventing nuclear factor of activated T-cells (NF-AT) dephosphorylation and translocation, thereby reducing IL-2 and other cytokine gene transcription.
Prophylaxis of organ rejection in patients receiving allogeneic liver, kidney, or heart transplants,Treatment of rejection in liver, kidney, and heart transplants,Off-label: Treatment of moderate to severe atopic dermatitis (topical),Off-label: Graft-versus-host disease (GVHD) prophylaxis and treatment
Prophylaxis of organ rejection in kidney, liver, and heart allogeneic transplants,Treatment of active rheumatoid arthritis (FDA-approved for moderate to severe),Treatment of psoriasis (FDA-approved for severe, recalcitrant cases),Off-label: nephrotic syndrome, aplastic anemia, ulcerative colitis, atopic dermatitis
0.1-0.2 mg/kg/day orally in two divided doses (immediate-release); 0.05-0.15 mg/kg/day orally once daily (extended-release); 0.01-0.05 mg/kg/day continuous IV infusion.
5-15 mg/kg/day orally in divided doses every 12 hours.
Terminal elimination half-life is approximately 8.7-21.7 hours in healthy volunteers and 18-41 hours in liver transplant recipients. Prolonged half-life in hepatic impairment requires dose adjustments.
Terminal half-life is approximately 8.4 hours (range 5-18 hours) in adult volunteers; prolonged in hepatic impairment.
Primarily metabolized by cytochrome P450 3A4 (CYP3A4) and to a lesser extent by CYP3A5 in the liver and intestinal wall. It is a substrate of P-glycoprotein (ABCB1).
Hepatic metabolism primarily via CYP3A4 enzyme; also substrate for CYP3A5. Metabolized to multiple metabolites with variable activity, including AM1 (hydroxylated), AM9 (N-demethylated), and AM4N (cyclized). Undergoes extensive first-pass metabolism.
Primarily fecal (approximately 93%), with renal excretion accounting for about 2.4% of the unchanged drug. Biliary excretion is a minor route for metabolites.
Primarily biliary/fecal (94%); renal excretion accounts for 6% (0.1% unchanged).
Approximately 99% bound, primarily to albumin and alpha-1-acid glycoprotein.
90-98% bound to plasma proteins, primarily lipoproteins, albumin, and alpha-1-acid glycoprotein.
Approximately 0.85-1.5 L/kg, reflecting extensive tissue distribution and binding to lymphocytes.
3.5 L/kg (range 1.2-4.8 L/kg) in renal transplant recipients; distribution is extensive and variable.
Oral: about 17-25% (variable due to first-pass metabolism and food effects); topical: minimal systemic absorption (less than 5% in healthy skin).
Oral bioavailability is 30% (range 10-60%), variable due to first-pass metabolism and food effects.
No standard dose adjustment for renal impairment; monitor renal function closely and reduce dose if nephrotoxicity occurs. For GFR < 30 m L/min, consider dose reduction by 50% and close monitoring.
GFR <30 m L/min: reduce dose by 50%.
Child-Pugh Class A: no adjustment; Child-Pugh Class B: reduce dose by 50%; Child-Pugh Class C: reduce dose by 75%; monitor trough levels.
Child-Pugh Class A: no adjustment; Class B: reduce dose by 50%; Class C: avoid use.
0.15-0.3 mg/kg/day orally in two divided doses (immediate-release); 0.03-0.1 mg/kg/day continuous IV infusion; titrate to target trough levels.
4-10 mg/kg/day orally in divided doses every 12 hours; adjusted to target trough levels.
Start at lower end of dosing range (0.05-0.1 mg/kg/day orally); monitor renal function and trough levels closely due to age-related decline in renal function.
Initiate at lower end of dosing range and titrate based on renal function and drug levels.
Increased susceptibility to infection and the possible development of lymphoma. Only physicians experienced in immunosuppressive therapy and management of transplant patients should prescribe tacrolimus. Patients receiving tacrolimus should be managed in facilities equipped and staffed with adequate laboratory and supportive medical resources.
Increased susceptibility to infection and development of lymphoma and other malignancies, particularly of the skin. Only physicians experienced in immunosuppressive therapy and management of transplant patients should prescribe cyclosporine.
Increased risk of lymphomas and other malignancies, particularly skin cancer,Increased susceptibility to infections, including opportunistic infections and reactivation of latent viruses (e.g., BK virus, CMV, EBV),Nephrotoxicity: acute and chronic renal impairment, monitor renal function closely,Neurotoxicity: tremors, headache, seizures, posterior reversible encephalopathy syndrome (PRES),Hyperkalemia: monitor serum potassium levels,Hypertension: monitor blood pressure and manage accordingly,Post-transplant diabetes mellitus: monitor blood glucose levels,Anaphylactic reactions: risk with intravenous formulation due to castor oil derivative (polyoxyl 60 hydrogenated castor oil) in some formulations,QT prolongation: caution in patients with risk factors or with drugs that prolong QT interval
Nephrotoxicity: Monitor renal function regularly; risk increased with high doses, other nephrotoxic drugs, or prolonged use.,Hepatotoxicity: Monitor liver function.,Hypertension: Common; require blood pressure control.,Neurotoxicity: Including tremor, convulsions, headache, and paresthesias.,Hyperkalemia: Monitor serum potassium, especially with potassium-sparing diuretics or ACE inhibitors.,Hypomagnesemia: Supplementation may be required.,Increased risk of infections and lymphoproliferative disorders.,Potential for anaphylactic reactions with IV formulation (due to Cremophor EL).,Carcinogenesis: Especially skin malignancies; minimize UV exposure.
Hypersensitivity to tacrolimus or any component of the formulation,Hypersensitivity to hydrogenated castor oil (present in some intravenous formulations)
Hypersensitivity to cyclosporine or any component of the formulation (including Cremophor EL for IV),Uncontrolled hypertension,Malignancy (except non-melanoma skin cancer) in patients with rheumatoid arthritis or psoriasis,Concomitant use with PUVA or UVB therapy, methotrexate, other immunosuppressive agents, or coal tar (for psoriasis patients),Abnormal renal function with uncontrolled hypertension (for psoriasis patients),Pregnancy (category C; additional risk of premature birth and low birth weight)
Grapefruit and grapefruit juice increase tacrolimus levels by inhibiting CYP3A4 and must be avoided. High-fat meals decrease absorption; consistent timing relative to meals recommended.
Grapefruit and grapefruit juice increase cyclosporine levels and must be avoided. High-potassium foods (e.g., bananas, oranges, potatoes) may increase hyperkalemia risk; monitor intake. Avoid St. John's wort as it reduces drug levels.
First trimester: Increased risk of congenital malformations including cardiac anomalies. Second and third trimesters: Risk of fetal growth restriction, preterm delivery, and neonatal hyperkalemia. Tacrolimus crosses the placenta.
First trimester: Cyclosporine crosses the placenta. Limited human data, but no major malformations attributed. Second and third trimesters: Risk of intrauterine growth restriction, prematurity, and low birth weight. Consider risk-benefit; avoid if possible, but may be used if essential.
Tacrolimus is excreted into breast milk. M/P ratio (concentration in milk:plasma) is approximately 0.3-0.9. It is recommended to use with caution; monitor infant for immunosuppression and tacrolimus trough levels.
Cyclosporine is excreted into breast milk. Milk-to-plasma ratio approximately 0.3-0.6. Potential for infant immunosuppression and growth inhibition. Weigh benefits against risks; monitor infant for adverse effects.
Increased dose requirements due to increased volume of distribution and clearance. Monitoring tacrolimus trough levels recommended every 1-2 weeks; dose adjustments to maintain therapeutic range (typically 5-15 ng/m L).
Pregnancy reduces cyclosporine oral bioavailability and increases clearance; dose may need to be increased by 20-50% to maintain therapeutic trough levels. Frequent level monitoring recommended, especially in third trimester. Postpartum dose reduction likely needed.
Monitor trough levels 2-3 days after dose changes; target 5-15 ng/m L for most indications. Use with caution in renal impairment due to nephrotoxicity. Strong CYP3A4 interaction potential; avoid grapefruit and adjust azole antifungals. Hypomagnesemia common; supplement as needed.
Monitor trough levels (target 100-400 ng/m L) and renal function closely. Calcineurin inhibitors cause nephrotoxicity; dose reduction may be necessary. Avoid use with potassium-sparing diuretics or ACE inhibitors due to hyperkalemia risk. Grapefruit increases levels; avoid coadministration. Remember to adjust dose for hepatic impairment.
Take consistently with or without food, but do not switch between.,Avoid grapefruit and grapefruit juice.,Report signs of infection, tremors, or kidney issues (swelling, decreased urine).,Do not take any new medications without consulting your doctor.,Use sun protection due to increased skin cancer risk.,Do not miss doses; if you do, take as soon as remembered unless near next dose.
Take with or without food consistently at the same times each day.,Do not consume grapefruit or grapefruit juice while on this medication.,Report signs of infection, tremors, or changes in urine output immediately.,Avoid live vaccinations and limit sun exposure due to increased skin cancer risk.,Do not stop or change dose without consulting your doctor.
"Tacrolimus, a potent CYP3A4 inhibitor, significantly decreases the metabolism of citalopram, a CYP3A4 substrate, leading to elevated citalopram plasma concentrations. This pharmacokinetic interaction increases the risk of dose-dependent adverse effects such as QT prolongation, serotonin syndrome, and central nervous system toxicity. Clinical outcomes may include corrected QT (QTc) interval prolongation, increasing the risk of torsade de pointes, and enhanced serotonergic effects requiring careful monitoring."
"Tacrolimus, a calcineurin inhibitor, primarily induces nephrotoxicity through afferent arteriolar vasoconstriction and direct tubular injury. Etofenamate, a nonsteroidal anti-inflammatory drug (NSAID) that inhibits cyclooxygenase (COX) enzymes, reduces prostaglandin synthesis, leading to decreased renal blood flow and glomerular filtration rate. Concomitant use synergistically impairs renal function, increasing the risk of acute kidney injury, hyperkalemia, and hypertension, particularly in patients with preexisting renal impairment or volume depletion."
"Tacrolimus, a calcineurin inhibitor and CYP3A4 substrate, may inhibit the metabolism of isoflurophate, a long-acting cholinesterase inhibitor used in glaucoma. This interaction can lead to increased systemic exposure of isoflurophate, potentially exacerbating cholinergic side effects such as bradycardia, hypersalivation, and bronchospasm. Clinically, patients may experience enhanced toxicity, including prolonged muscle weakness or respiratory depression, especially in those with compromised hepatic function."
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about TACROLIMUS vs GENGRAF, answered by our medical review team.
TACROLIMUS is a Calcineurin Inhibitor that works by Tacrolimus is a calcineurin inhibitor. It binds to FK506-binding protein 12 (FKBP12), forming a complex that inhibits calcineurin phosphatase activity. This prevents dephosphorylation and nuclear translocation of nuclear factor of activated T-cells (NFAT), thereby inhibiting transcription of interleukin-2 (IL-2) and other cytokines, leading to suppressed T-cell activation and proliferation.. GENGRAF is a Calcineurin Inhibitor Immunosuppressant that works by Calcineurin inhibitor; binds to cyclophilin, inhibits calcineurin-dependent T-cell activation, preventing nuclear factor of activated T-cells (NF-AT) dephosphorylation and translocation, thereby reducing IL-2 and other cytokine gene transcription.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between TACROLIMUS and GENGRAF depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of TACROLIMUS is: 0.1-0.2 mg/kg/day orally in two divided doses (immediate-release); 0.05-0.15 mg/kg/day orally once daily (extended-release); 0.01-0.05 mg/kg/day continuous IV infusion.. The standard adult dose of GENGRAF is: 5-15 mg/kg/day orally in divided doses every 12 hours.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between TACROLIMUS and GENGRAF in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. TACROLIMUS is classified as Category D/X. First trimester: Increased risk of congenital malformations including cardiac anomalies. Second and third trimesters: Risk of fetal growth restriction, preterm delivery, and neonat. GENGRAF is classified as Category C. First trimester: Cyclosporine crosses the placenta. Limited human data, but no major malformations attributed. Second and third trimesters: Risk of intrauterine growth restriction,. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.