Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ELIDEL vs AZASAN
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Inhibits T-cell activation by binding to macrophilin-12 (FKBP-12) and inhibiting calcineurin, thereby blocking cytokine transcription.
Azathioprine is a purine analog that inhibits purine synthesis, thereby interfering with DNA and RNA synthesis. It is metabolized to 6-mercaptopurine, which inhibits T-cell activation and proliferation, leading to immunosuppression.
Atopic dermatitis unresponsive to or intolerant of other topical treatments,Off-label: psoriasis, vitiligo, rosacea, contact dermatitis, lichen sclerosus, cutaneous lupus erythematosus
Renal transplant rejection prophylaxis,Rheumatoid arthritis,Off-label: inflammatory bowel disease (Crohn's disease, ulcerative colitis), lupus nephritis, autoimmune hepatitis, pemphigus vulgaris, myasthenia gravis, Behçet's disease, dermatomyositis, polymyositis
Apply a thin layer of 1% cream to affected areas twice daily.
1-3 mg/kg/day orally once daily or divided twice daily; maximum dose 2.5 mg/kg/day for rheumatoid arthritis; usual dose 50-150 mg/day.
Terminal elimination half-life: 30–45 hours (mean 35 hours) following topical application; clinically, twice-daily dosing ensures therapeutic concentrations.
Terminal elimination half-life of azathioprine is approximately 4.5 hours (range 2–6 h), while its active metabolite 6-mercaptopurine has a half-life of 0.5–2 hours. Clinical context: Renal impairment prolongs half-life.
Metabolized primarily by CYP3A4; major metabolite O-demethylated pimecrolimus.
Metabolized via xanthine oxidase and thiopurine methyltransferase (TPMT) to active and inactive metabolites. Co-administration with allopurinol inhibits xanthine oxidase, requiring dose reduction of azathioprine.
Renal (negligible, <1% unchanged) and biliary/fecal (approximately 97% as metabolites); less than 1% of the dose is excreted renally as unchanged drug.
Renal: 88% as 6-mercaptopurine and metabolites; biliary: <10%
99% bound to plasma proteins (primarily albumin and alpha-1-acid glycoprotein).
30% bound to plasma proteins, primarily albumin.
Vd ~ 10 L/kg (extensive tissue distribution); suggests significant extravascular binding and penetration into tissues.
0.8–1.0 L/kg, indicating extensive distribution into tissues.
Topical: Systemic bioavailability is approximately 4% (range 1–7%) of applied dose; absorption increases with extent of skin lesion and thickness of application.
Oral: 41–47% (azathioprine); 100% for IV administration.
No dose adjustment required for any degree of renal impairment.
GFR >50 m L/min: no adjustment; GFR 10-50 m L/min: 75% of normal dose; GFR <10 m L/min: 50% of normal dose.
No formal studies in hepatic impairment; use caution in severe impairment.
Child-Pugh Class A: no adjustment; Child-Pugh Class B: reduce dose by 50%; Child-Pugh Class C: contraindicated.
Apply a thin layer of 1% cream twice daily for children aged 2 years and older; not indicated for children under 2 years.
2-3 mg/kg/day orally once daily; initial dose 1 mg/kg/day in divided doses; not recommended in children <1 year.
No specific dose adjustment recommended; apply a thin layer of 1% cream twice daily as for adults.
Start at low end of dosing range (50 mg once daily); monitor renal function and adjust accordingly.
Long-term safety of topical calcineurin inhibitors has not been established; rare cases of malignancy (e.g., lymphoma, skin cancer) have been reported; use should be limited to short-term and intermittent treatment.
Chronic immunosuppression increases the risk of malignancy, particularly lymphoma and skin cancer. Patients should be monitored for neoplasia. The drug should be used only if potential benefits outweigh risks.
Increased risk of infections (e.g., eczema herpeticum, varicella zoster); avoid use on malignant or premalignant skin conditions; lymphadenopathy; photosensitivity; not recommended in patients with Netherton syndrome; potential for systemic immunosuppression; monitor for local irritation.
Hematologic toxicity (leukopenia, thrombocytopenia, anemia) - monitor blood counts. Hepatotoxicity. Increased infection risk. Hypersensitivity reactions. TPMT deficiency increases toxicity risk. Monitor for pancreatitis, especially in Crohn's patients. Avoid live vaccines. Photosensitivity and skin cancer risk.
Hypersensitivity to pimecrolimus or any component of the formulation; history of malignancy; application to areas of active infection; Netherton syndrome; immunocompromised patients.
Hypersensitivity to azathioprine or 6-mercaptopurine. Pregnancy (category D) unless potential benefit justifies risk. Lactation. Severe hepatic impairment. Myelosuppression or active infection. Concurrent use with allopurinol without dose adjustment.
No known food interactions. Avoid grapefruit juice as it may increase drug levels (CYP3A4 inhibition).
No significant food interactions. May be taken with food to reduce gastrointestinal upset. Avoid concurrent use with raw or undercooked meats to reduce risk of infection due to immunosuppression.
FDA Pregnancy Category C. Systemic exposure is minimal after topical application, but animal studies have shown developmental toxicity. No adequate human studies; risk cannot be excluded. Avoid in pregnancy unless clearly needed.
Azathioprine is FDA Pregnancy Category D. First trimester: Associated with congenital anomalies (e.g., atrial septal defect, limb defects) in case reports, but risk may be lower than with other immunosuppressants. Second and third trimesters: Risk of fetal growth restriction, preterm delivery, and neonatal immunosuppression. Avoid unless benefit outweighs risk.
Not recommended. Pimecrolimus is excreted in milk in animal studies; unknown in humans. M/P ratio not available. Potential for serious adverse reactions in nursing infants.
Azathioprine is excreted into breast milk in small amounts; milk-to-plasma ratio approximately 0.1. Infant exposure is low, but theoretical risk of immunosuppression. Weigh benefits against risks; consider monitoring infant for leukopenia and infections.
No dose adjustment necessary; use minimal amount to control symptoms. Systemic absorption is negligible, so pharmacokinetic changes in pregnancy do not alter dosing.
Increased clearance and reduced bioavailability during pregnancy may require dose increase to maintain therapeutic levels; monitor thiopurine metabolite levels (6-TGN, 6-MMP) and adjust accordingly. Often no change required if stable disease.
Topical calcineurin inhibitor for atopic dermatitis, reserved as second-line therapy for mild-to-moderate eczema due to boxed warning for rare malignancy risk. Apply thin layer only; avoid occlusive dressings. Do not use in immunocompromised patients. Intermittent use is recommended; continuous long-term use safety not established.
Azasan (azathioprine) is a prodrug of 6-mercaptopurine. Screen for TPMT deficiency before initiation to avoid severe myelosuppression. Monitor CBC and liver function weekly for first month, then monthly. Corticosteroid-sparing agent in autoimmune conditions. Avoid live vaccines during therapy.
Apply only to affected skin areas; avoid eyes, mouth, and open wounds.,Use for short durations; do not use continuously for extended periods.,Avoid sun exposure and tanning beds; use sunscreen on treated areas.,Do not cover treated skin with bandages or wraps unless instructed.,Report any signs of infection, skin burning, or new skin growths to your doctor.,This drug is for external use only; wash hands after application unless treating hands.,Do not use if you have a weakened immune system or active skin infection.
Take exactly as prescribed; do not change dose without consulting your doctor.,Report any signs of infection, unusual bruising/bleeding, or fatigue immediately.,Avoid exposure to individuals with infections; maintain good hand hygiene.,Use effective contraception during treatment and for at least 3 months after stopping.,Do not receive live vaccines (e.g., MMR, varicella) while taking this medication.,Limit sun exposure; use sunscreen and protective clothing due to increased skin cancer risk.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about ELIDEL vs AZASAN, answered by our medical review team.
ELIDEL is a Topical Calcineurin Inhibitor that works by Inhibits T-cell activation by binding to macrophilin-12 (FKBP-12) and inhibiting calcineurin, thereby blocking cytokine transcription.. AZASAN is a Immunosuppressant that works by Azathioprine is a purine analog that inhibits purine synthesis, thereby interfering with DNA and RNA synthesis. It is metabolized to 6-mercaptopurine, which inhibits T-cell activation and proliferation, leading to immunosuppression.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ELIDEL and AZASAN 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 ELIDEL is: Apply a thin layer of 1% cream to affected areas twice daily.. The standard adult dose of AZASAN is: 1-3 mg/kg/day orally once daily or divided twice daily; maximum dose 2.5 mg/kg/day for rheumatoid arthritis; usual dose 50-150 mg/day.. 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 ELIDEL and AZASAN 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. ELIDEL is classified as Category C. FDA Pregnancy Category C. Systemic exposure is minimal after topical application, but animal studies have shown developmental toxicity. No adequate human studies; risk cannot be ex. AZASAN is classified as Category C. Azathioprine is FDA Pregnancy Category D. First trimester: Associated with congenital anomalies (e.g., atrial septal defect, limb defects) in case reports, but risk may be lower th. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.