Dosing & Uses
Dosage Forms & Strengths
tablet
- 50mg
- 75mg
- 100mg
powder for injection
- 100mg/vial
Kidney Transplantation
Prevention of transplant rejection
3-5 mg/kg/day IV/PO initially on day of transplant; 1 to 3 days prior to transplantation also reported (rare)
Maintenance: 1-3 mg/kg/day IV/PO
Rheumatoid Arthritis
1 mg/kg/day IV/PO initially in single daily dose or divided q12hr; after 6-8 weeks, increase by 0.5 mg/kg/day every 4 weeks; not to exceed 2.5 mg/kg/day
Maintenance: Reduce daily dose by 0.5 mg/kg every 4 weeks until lowest effective dosage is reached
Lupus Nephritis (Off-label)
Induction and maintenance therapy for lupus nephritis (2012 American College of Rheumatology guidelines)
2 mg/kg/day PO with or without low-dose corticosteroids
Crohn Disease (Off-label)
Maintenance, remission, or reduction of steroid
Ulcerative Colitis (Off-label)
Maintenance, remission, or reduction of steroid
Chronic Refractory Thrombocytopenic Purpura (Off-label)
1-2 mg/kg PO once daily to maximum daily dose of 150 mg for at least 3-6 months before typical response is observed
Dosing considerations
- Lower dosage (100 mg/day) is reported effective in some patients
- Longer treatment duration (up to 84 months) is reported in some patients
Dosage Forms & Strengths
tablet
- 50mg
- 75mg
- 100mg
powder for injection
- 100mg/vial
Juvenile Idiopathic Arthritis
1 mg/kg/day IV/PO initially in single daily dose or divided q12hr; may be increased by 0.5 mg/kg/day after 6-8 weeks, then by 0.5 mg/kg/day every 4 weeks; not to exceed 2.5 mg/kg/day
Maintenance: Reduce daily dose by 0.5 mg/kg every 4 weeks until lowest effective dosage is reached
Transplantation (Off-label)
Prevention of transplant rejection
3-5 mg/kg/day IV/PO initially on day of transplant or 3 days before transplant (rare)
Maintenance: 1-3 mg/kg/day IV/PO
Lupus Nephritis (Off-label)
Induction and maintenance therapy for lupus nephritis (2012 American College of Rheumatology guidelines)
<12 years: Safety and efficacy not established
>12 years: 2 mg/kg/day PO with or without low-dose corticosteroids
Interactions
Interaction Checker
No Results

Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor

Adverse Effects
>10%
Leukopenia (28-50%)
Infection (20%)
<1%
Lymphoma
Frequency Not Defined
Abdominal pain
Alopecia
Arthralgia
Bacterial, fungal, protozoal, viral infections
Bone marrow suppression
Diarrhea
Fever
Hepatotoxicity
Macrocytic anemia
Myalgia
Nausea or vomiting
Rash
Skin cancer
Steatorrhea
Sweet syndrome (acute febrile neutrophilic dermatosis)
Thrombocytopenia
Warnings
Black Box Warnings
Chronic immunosuppression with this purine antimetabolite increases neoplasia risk, mutagenic risk, and hematologic toxicities
Reported malignancies include posttransplant lymphoma and hepatosplenic T-cell lymphoma (HSTCL) in patients with inflammatory bowel disease
Prescribing physicians should be familiar with mutagenic potential and with possible hematologic toxicities
Contraindications
Documented hypersensitivity
Pregnancy, lactation
Rheumatoid arthritis: Patients previously treated with alkylating agents
Cautions
Long-term use increases risk of neoplasia
Increased risk of infection and hepatotoxicity; monitor liver function periodically; hepatic sinudoidal obstruction syndrome reported; discontinue therapy if suspected
Cases of JC virus-associated infection resulting in progressive multifocal leukoencephalopathy (PML), sometimes fatal, reported in patients treated with immunosuppressants, including azathioprine
Severe leukopenia, thrombocytopenia, anemias including macrocytic anemia, and/or pancytopenia may occur; severe bone marrow suppression may also occur; patients with or nucleotide diphosphatase (NUDT15) deficiency may be at an increased risk of myelotoxicity if patient receiving conventional doses of drug; delayed hematologic suppression may occur; prompt reduction in dosage or temporary withdrawal of drug may be necessary if there is rapid fall in or persistently low leukocyte count, or other evidence of bone marrow depression; leukopenia does not correlate with therapeutic effect; therefore dose should not be increased intentionally to lower white blood cell count
In patients with severe myelosuppression, consider evaluation for TPMT and NUDT15 deficiency; consider alternative therapy in patients with homozygous TPMT or NUDT15 deficiency and reduced dosages in patients with heterozygous deficiency
Patients receiving immunosuppressants, are at increased risk for bacterial, viral, fungal,protozoal, and opportunistic infections, including reactivation of latent infections; these infections may lead to serious, including fatal outcomes
Frequency of gastrointestinal adverse effects (nausea and vomiting) may decrease with dividing dose or administering after meals
Hepatosplenic T-cell lymphoma
- Rare postmarketing cases of HSTCL reported primarily in adolescent and young adult patients with Crohn disease and ulcerative colitis treated with tumor necrosis factor (TNF) blockers
- Reports have also included 1 patient being treated for psoriasis and 2 patients being treated for rheumatoid arthritis
- HSTCL is an aggressive, rare type of T-cell lymphoma that is usually fatal
- Most reported cases with TNF blockers have occurred in context of concomitant treatment with azathioprine or 6-mercaptopurine (6-MP), though cases have been reported with azathioprine or 6-MP alone
- In the FDA Adverse Event Reporting System (AERS) database, the literature, and the HSTCL Cancer Survivors' Network, HSTCL cases have been identified in association with the following drugs: infliximab (20), etanercept (1), adalimumab (2), infliximab/adalimumab (5), certolizumab (0), golimumab (0), azathioprine (12), 6-MP (3)
Pregnancy & Lactation
Pregnancy category: D
Lactation: Drug excreted at low levels in breast milk; use not recommended
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
Purine antimetabolite, converted to 6-MP; may inhibit synthesis of DNA, RNA, and proteins; interferes with cellular metabolism; may inhibit mitosis
Absorption
Well absorbed orally
Duration: Variable (crosses placenta)
Peak plasma time: PO, 1-2 hr
Peak plasma concentration: <1 mcg/mL
Distribution
Protein bound: 30%
Metabolism
Metabolized in liver
Metabolites: 6-MP, 6-thiouric acid
Elimination
Half-life: Parent drug, 12 min; 6-MP, 0.7-3 hr; slightly prolonged in end-stage renal disease
Dialyzable: Partially
Excretion: Urine (primarily as metabolites)
Administration
Oral suspension of 50 mg/mL requires extemporaneous compounding by pharmacist
IV Incompatibilities
Stable in neutral or acid solutions; in alkaline solutions, hydrolyzed to 6-MP
IV Administration
Can be administered by IV push over 5 minutes at concentration not exceeding 10 mg/mL
Can be further diluted with NS or D5W and administered by intermittent infusion over 30-60 minutes (usual approach); however, infusions over periods ranging from 5 minutes to 8 hours have been done
Storage
Store powder at room temperature (25°C); reconstituted solution is stable for 2 weeks at room temperature but may be less stable under refrigeration
Protect from light
Because there are no preservatives, drug must be used within 24 hours
Images
BRAND | FORM. | UNIT PRICE | PILL IMAGE |
---|---|---|---|
azathioprine oral - | 50 mg tablet | ![]() | |
azathioprine oral - | 50 mg tablet | ![]() | |
azathioprine oral - | 50 mg tablet | ![]() | |
azathioprine oral - | 75 mg tablet | ![]() | |
azathioprine oral - | 50 mg tablet | ![]() | |
azathioprine oral - | 100 mg tablet | ![]() | |
azathioprine oral - | 100 mg tablet | ![]() | |
azathioprine oral - | 50 mg tablet | ![]() | |
azathioprine oral - | 75 mg tablet | ![]() | |
Azasan oral - | 100 mg tablet | ![]() | |
Azasan oral - | 75 mg tablet | ![]() | |
Imuran oral - | 50 mg tablet | ![]() |
Copyright © 2010 First DataBank, Inc.
Formulary
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