Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
AZATHIOPRINE vs LUPKYNIS
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Azathioprine is a purine analog that inhibits purine nucleotide synthesis, thereby suppressing DNA replication and cell proliferation. It is converted to 6-mercaptopurine, which acts as a purine antagonist, inhibiting de novo purine synthesis and interfering with RNA and DNA synthesis, particularly in rapidly dividing cells such as T-lymphocytes.
Calcineurin inhibitor immunosuppressant that binds to cyclophilin A, inhibiting calcineurin activity, which prevents dephosphorylation and activation of nuclear factor of activated T-cells (NFAT), thereby reducing cytokine production and T-cell activation.
Renal transplant rejection prophylaxis (FDA),Rheumatoid arthritis (FDA),Off-label: autoimmune hepatitis, systemic lupus erythematosus, inflammatory bowel disease (Crohn's disease, ulcerative colitis), pemphigus, myasthenia gravis, dermatomyositis/polymyositis,Off-label: myelodysplastic syndrome, refractory immune thrombocytopenic purpura, atopic dermatitis, Behçet's syndrome
Treatment of lupus nephritis in combination with a background immunosuppressive therapy
1.5 to 2.5 mg/kg orally once daily; typical adult dose 50-150 mg/day orally. Intravenous dose is 3-5 mg/kg/day as a slow infusion over 30-60 minutes.
23.7 mg orally twice daily with food.
Terminal elimination half-life of azathioprine is approximately 2–5 hours; its active metabolite 6-mercaptopurine has a half-life of 1–2 hours, but 6-thioguanine nucleotides accumulate in red blood cells with a half-life of several days, correlating with myelosuppression.
Terminal elimination half-life approximately 30 hours; supports once-daily dosing; steady-state reached by day 4.
Azathioprine is metabolized by xanthine oxidase (XO) and thiopurine methyltransferase (TPMT) to active (6-mercaptopurine) and inactive metabolites. 6-Mercaptopurine is further metabolized by XO to 6-thiouric acid and by TPMT to 6-methylmercaptopurine. Genetic deficiency of TPMT increases risk of toxicity.
Primarily metabolized by CYP3A4; minor contribution from CYP3A5.
Renal (approximately 2% as unchanged drug, 30% as 6-thiouric acid and other metabolites); biliary/fecal (minor, <10% as metabolites).
Primarily hepatic metabolism; <1% excreted unchanged in urine; approximately 66% of total radioactivity recovered in feces (mainly metabolites) and 22% in urine (mainly metabolites).
Approximately 30% bound, primarily to albumin.
Greater than 99% bound to plasma proteins, primarily albumin and alpha-1-acid glycoprotein.
0.8–1.0 L/kg, indicating distribution into total body water; extensive distribution into tissues including liver and erythrocytes.
Apparent Vd/F ~24 L (approximately 0.34 L/kg assuming 70 kg); indicates distribution into tissues.
Oral bioavailability of azathioprine is 60–80% (mean 70%) with interindividual variability; absorption may be reduced by food.
Oral bioavailability approximately 35% (range 20–50%) under fasting conditions; high-fat meal reduces Cmax and AUC by about 50%.
GFR >50 m L/min: no adjustment. GFR 10-50 m L/min: administer 75% of normal dose. GFR <10 m L/min: administer 50% of normal dose. Hemodialysis: administer 50% of normal dose after dialysis.
No dose adjustment required for GFR ≥30 m L/min. Avoid use in severe renal impairment (GFR <30 m L/min) due to lack of data.
Child-Pugh Class A: no adjustment. Child-Pugh Class B: reduce dose by 25-50%. Child-Pugh Class C: contraindicated or use with extreme caution; reduce dose by at least 50%.
Child-Pugh Class A: No adjustment. Child-Pugh Class B: Reduce dose to 15.8 mg orally twice daily. Child-Pugh Class C: Not recommended.
1.5 to 2.5 mg/kg orally once daily; maximum 150 mg/day. For inflammatory bowel disease: 2-3 mg/kg/day. Intravenous: 3-5 mg/kg/day as a slow infusion.
Safety and efficacy not established in pediatric patients; no approved dose.
Initiate at lower end of dosing range (1.5 mg/kg/day) due to potential for decreased renal and hepatic function; monitor renal function and hematologic parameters closely.
No specific dose adjustment required; monitor renal function due to age-related decline.
Malignancy: Patients receiving immunosuppressive therapy including azathioprine have an increased risk of developing lymphoma and other malignancies, particularly skin cancers. The risk is related to the duration and intensity of immunosuppression. Hematologic toxicity: Severe leukopenia, thrombocytopenia, and anemia, which may be dose-related, can occur. Regular monitoring of blood counts is required. Hepatotoxicity: Hepatotoxicity, including fatal liver injury, has been reported, particularly at high doses.
Increased risk of infection and lymphoma; increased risk of nephrotoxicity and hypertension; increased risk of neurotoxicity.
Hematologic monitoring: regular CBCs; Increased risk of infection; Hepatotoxicity; Pancreatitis; Carcinogenicity (lymphoma, skin cancer); TPMT deficiency increases myelotoxicity; Vaccination (live vaccines contraindicated); Renal and hepatic impairment; Drug interactions: allopurinol (reduce dose by 75%), ACE inhibitors (anemia), warfarin (anticoagulant effect decreased).
Nephrotoxicity and hypertension require regular monitoring. Neurotoxicity including posterior reversible encephalopathy syndrome (PRES). Increased susceptibility to infections including opportunistic infections. Malignancies including lymphoma. Monitor for Epstein-Barr virus serology. Use with caution with CYP3A4 inhibitors and inducers. Avoid live vaccines.
Hypersensitivity to azathioprine or 6-mercaptopurine; Pregnancy (unless benefit outweighs risk) - Category D; Lactation; Patients with TPMT deficiency (increased risk of severe myelotoxicity); Severely depressed bone marrow function; Active infections; Concurrent use of live vaccines; Pre-existing malignancy (except in organ transplantation context).
Concurrent use with chronic immunosuppressive therapies other than mycophenolate mofetil (MMF) or mycophenolic acid (MPA). Known hypersensitivity to voclosporin or any component of the formulation.
No known significant food interactions. Avoid grapefruit juice? (No interaction reported). Maintain consistent diet; no specific restrictions. Limit alcohol due to hepatotoxicity risk.
Avoid grapefruit and grapefruit juice as they increase voclosporin exposure. No other specific food interactions are known.
Azathioprine is pregnancy category D. First trimester: increased risk of congenital anomalies including ventricular septal defects, limb defects, and esophageal atresia. Second and third trimesters: risk of intrauterine growth restriction, preterm birth, and neonatal immunosuppression (leukopenia, thrombocytopenia). Use only if benefit outweighs risk.
LUPKYNIS (voclosporin) is a calcineurin inhibitor. Based on animal studies, there is a risk of fetal harm in all trimesters. In rats and rabbits, voclosporin administration during organogenesis resulted in increased embryofetal mortality and reduced fetal weight at maternally toxic doses. There are no adequate human studies. Avoid use during pregnancy unless potential benefit outweighs risk.
Azathioprine is excreted into breast milk in low concentrations. M/P ratio is approximately 0.7. Nursing infants of mothers on azathioprine have not shown adverse effects; however, theoretical risk of immunosuppression exists. Caution is advised; monitor infant for increased infections.
It is unknown if voclosporin is excreted in human milk. In animal studies, voclosporin and its metabolites were detected in milk of lactating rats. No M/P ratio available for humans. Due to potential for serious adverse reactions in nursing infants, advise women not to breastfeed during treatment and for 4 weeks after last dose.
Pharmacokinetic changes in pregnancy include increased clearance and decreased absorption. Dose may need adjustment to maintain therapeutic efficacy. Close monitoring of disease activity and drug levels (6-thioguanine nucleotide levels) is recommended. No standard dose adjustment; individualization required.
No specific dose adjustments are established for pregnancy. However, pregnancy can increase voclosporin clearance due to expanded plasma volume and enhanced metabolism. Consider therapeutic drug monitoring if available, and adjust dose to maintain therapeutic trough levels (target 30-60 ng/m L) as needed.
Monitor CBC and LFTs weekly for first month, then biweekly for 2 months, then monthly. TPMT genotype testing before initiation. Avoid concurrent allopurinol unless dose reduced to 25% of original. Use with caution in renal impairment. May cause hepatotoxicity, pancreatitis, or lymphoproliferative disorders.
Monitor for hematuria, proteinuria, and e GFR during treatment. Lupkynis (voclosporin) is a calcineurin inhibitor; do not co-administer with other CNIs or strong CYP3A4 inhibitors. Reduce dose in patients with e GFR <45 m L/min per 1.73 m². Concomitant use with mycophenolate mofetil and corticosteroids is standard. Check blood pressure and serum potassium regularly. Live vaccines contraindicated.
Take exactly as prescribed; do not double dose if missed.,Avoid live vaccines during treatment and for 3 months after stopping.,Report any signs of infection, unexplained bruising/bleeding, or jaundice immediately.,Limit sun exposure and use sunscreen due to increased skin cancer risk.,Do not take allopurinol or other new medications without consulting doctor.,Maintain adequate hydration to reduce risk of hepatotoxicity.,Regular blood tests are required to monitor for side effects.
Take exactly as prescribed; do not stop or change dose without consulting your doctor.,You will need regular blood and urine tests to monitor kidney function and drug levels.,Report any signs of infection (fever, sore throat), high blood pressure (severe headache, vision changes), or changes in urine output/color.,Avoid grapefruit and grapefruit juice during treatment.,Do not receive live vaccines while taking this medication.,Use effective contraception during treatment and for 12 weeks after last dose if of childbearing potential.,Tell your doctor about all medications, including over-the-counter drugs and supplements.
"Azathioprine may reduce the therapeutic efficacy and cardiotoxic effects of digitoxin by accelerating its metabolism through induction of cytochrome P450 enzymes, particularly CYP3A4. This interaction can lead to decreased digitoxin serum concentrations, potentially resulting in loss of heart rate control in patients with atrial fibrillation or heart failure. Conversely, the cardiotoxic risk of digitoxin is diminished, but the therapeutic goal may be compromised."
"Azathioprine and fingolimod both suppress lymphocyte function, leading to additive or synergistic immunosuppression. This combination increases the risk of severe infections, including opportunistic infections, due to profound immune system suppression. Clinically, patients may present with prolonged lymphopenia, increased susceptibility to infections, and potential reactivation of latent viruses such as JC virus (causing progressive multifocal leukoencephalopathy) or cytomegalovirus."
"Azathioprine, an immunosuppressant that acts as a prodrug for 6-mercaptopurine, can increase the myelosuppressive effects of benazepril, an ACE inhibitor. This interaction is likely due to additive bone marrow suppression, leading to an elevated risk of leukopenia, anemia, and thrombocytopenia, especially in patients with renal impairment or concomitant use of other myelosuppressive agents."
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about AZATHIOPRINE vs LUPKYNIS, answered by our medical review team.
AZATHIOPRINE is a Immunosuppressant that works by Azathioprine is a purine analog that inhibits purine nucleotide synthesis, thereby suppressing DNA replication and cell proliferation. It is converted to 6-mercaptopurine, which acts as a purine antagonist, inhibiting de novo purine synthesis and interfering with RNA and DNA synthesis, particularly in rapidly dividing cells such as T-lymphocytes.. LUPKYNIS is a Calcineurin Inhibitor Immunosuppressant that works by Calcineurin inhibitor immunosuppressant that binds to cyclophilin A, inhibiting calcineurin activity, which prevents dephosphorylation and activation of nuclear factor of activated T-cells (NFAT), thereby reducing cytokine production and T-cell activation.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between AZATHIOPRINE and LUPKYNIS 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 AZATHIOPRINE is: 1.5 to 2.5 mg/kg orally once daily; typical adult dose 50-150 mg/day orally. Intravenous dose is 3-5 mg/kg/day as a slow infusion over 30-60 minutes.. The standard adult dose of LUPKYNIS is: 23.7 mg orally twice daily with food.. 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 AZATHIOPRINE and LUPKYNIS 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. AZATHIOPRINE is classified as Category D/X. Azathioprine is pregnancy category D. First trimester: increased risk of congenital anomalies including ventricular septal defects, limb defects, and esophageal atresia. Second and. LUPKYNIS is classified as Category C. LUPKYNIS (voclosporin) is a calcineurin inhibitor. Based on animal studies, there is a risk of fetal harm in all trimesters. In rats and rabbits, voclosporin administration during . Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.