Azasan Azathioprine 100 mg Tablet, 100-count
🆔 Identity & classification
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🏷️ RxNorm drug class
This medicine belongs to the Purine Antimetabolite class.
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🏭 Manufacturer & labeler
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🩺 Clinical
Azathioprine is used with other medications to prevent transplant rejection (attack of the transplanted organ by the immune system) in people who received kidney transplants. It is also used to treat severe rheumatoid arthritis (a condition in which the body attacks its own joints, causing pain, swelling, and loss of function) when other medications and treatments have not helped. Azathioprine is in a class of medications called immunosuppressants. It works by decreasing the activity of the body's immune system so it will not attack the transplanted organ or the joints.
Read the full MedlinePlus article ↗- You're right that it treats two quite different conditions, but the common thread is the immune system. After a kidney transplant, your immune system sees the new kidney as foreign...
- What exactly is azathioprine being used for — it seems like a drug used for very different things?
- Azathioprine is not a quick fix — it typically takes 6 to 8 weeks before you start feeling any improvement, and your doctor will usually give it a full 12 weeks before deciding if...
- How long will it take before I notice it working for my rheumatoid arthritis?
Patient education
Supplement & herbal interactions
Some supplements/herbs that may interact with Azathioprine — tap one for details:
Azathioprine may be associated with lower levels of 1 nutrient — worth a chat with your pharmacist, not a cause for alarm.
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💊 What it looks like
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🧪 Inactive Ingredients / Excipients
Inactive ingredients, also called excipients, are components of the drug product other than the active ingredient. They may include fillers, dyes, coatings, preservatives, flavors, or other formulation ingredients.
💡 Tap an ingredient (hover on desktop) to see what it is and why it’s used.
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UNII EWQ57Q8I5X
Lactose monohydrate is a natural sugar derived from milk. It serves as a filler and binder in tablets and capsules, helping create the proper size, texture, and consistency of the medicine.
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UNII 70097M6I30
Magnesium stearate is a salt made from magnesium and stearic acid, a fatty substance. It's used in tablets and capsules as a lubricant and glidant to help ingredients flow smoothly during manufacturing and prevent sticking.
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UNII FZ989GH94E
Povidone is a synthetic polymer made from a plastic-like material. It acts as a binder to hold tablet ingredients together and as a disintegrant to help the tablet break apart in your stomach so the medicine can be absorbed.
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UNII O8232NY3SJ
A plant-based carbohydrate derived from corn kernels. It acts as a filler to add bulk, a binder to hold ingredients together, and a disintegrant to help the tablet break apart in your stomach for absorption.
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UNII 4ELV7Z65AP
Stearic acid is a fatty acid derived from plant or animal sources. It acts as a binder and lubricant in tablets and capsules, helping them hold together and flow smoothly during manufacturing.
5 inactive ingredients listed in the exact product block matched to this NDC.
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ingredient classCode="IACT" elements from the exact product block matched by this NDC. Label-section narrative from DailyMed / the openFDA label index is shown separately when available.Inactive ingredient FAQ
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💲 Pricing
A drug doesn't have one price. Each row is a different public payment system, and none is what you'd pay at the counter — that depends on your insurance. The ⓘ on each row explains what it measures.
| Price system | Per each | Per package |
|---|---|---|
| Retail pharmacies payNADAC · weekly | Not in the retail survey — common for institutional, discontinued, or low-volume packs. | |
| Medicaid paysCMS SDUD · 12 mo | No recent Medicaid claims on file for this NDC — rare and low-volume NDCs are suppressed in the public data. | |
| Medicare drug plans payPart D · Q2 2026 | $5.94 | $593.76 / 100 tablets |
| Medicare Part B allowsASP · J7500 | $0.136 / J7500 unit | — |
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🧾 Billing & reimbursement
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🔁 Therapeutic equivalents
| Product | Labeler | Pack | NADAC/unit | TE | Status | Price vs. this |
|---|---|---|---|---|---|---|
| Azathioprine 100 mg 60219-2037-01 | Amneal | 100 tablets | $3.034 | AB | Availability likely | — |
| Azathioprine 100 mg 68382-0120-01 | Zydus | 100 tablets | $3.034 | AB | Availability likely | — |
| Azathioprine 100 mg 68682-0241-01 | Oceanside | 100 tablets | $6.142 | AB | FDA listed | — |
| Azathioprine 100 mg 42291-0063-01 | AvKARE | 100 tablets | — | AB | FDA listed | — |
| Azasan 100 mgthis 65649-0241-41 | Salix | 100 tablets | — | AB | FDA listed | — |
| Azathioprine 100 mg 67877-0495-01 | Ascend | 100 tablets | — | AB | FDA listed | — |
| Azathioprine 100 mg 70771-1141-01 | Zydus | 100 tablets | — | AB | FDA listed | — |
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⏳ Availability & generic status
This product is an FDA-approved generic. Other versions of the same drug are listed under Therapeutic equivalents, least expensive first.
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📊 Medicare Part D spend CMS · PART D · 2025 (Q1-Q4)
🔬 Reported adverse events (FAERS)
Top reported reactions
Reporter sex
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📦 Packaging — all sizes for this product
| Package NDC | Description | Marketing start | Status |
|---|---|---|---|
| 65649-0241-41 You're viewing this | 100 TABLET in 1 BOTTLE (65649-241-41) | 2003-04-01 | Active |
🧭 About this NDC listing & data coverage
What data is (and isn’t) available for this NDC — tap to expand
| NDC identity (package / product / labeler codes) | ✓ Available |
| Labeler | ✓ Available |
| Product & package description | ✓ Available |
| Marketing category & status | ✓ Available |
| Active ingredient / dosage form / route | ✓ Available |
| FDA label (SPL via DailyMed) | ✓ Available |
| Package photos | ✓ Available |
| Inactive ingredients (structured) | ✓ Available |
| NADAC pharmacy acquisition price (CMS) | — Not published for this NDC CMS publishes NADAC only for NDCs reported in its retail-pharmacy survey. |
| Orange Book / therapeutic-equivalence data | ✓ Available |
| HCPCS J-code billing crosswalk | ✓ Available |
| Medicaid utilization (CMS SDUD) | — Not published for this NDC CMS reports utilization only for NDCs with Medicaid claims above its privacy threshold. |
Questions about this listing
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📄 Full prescribing information FDA SPL
🚨 Boxed Warning ▾
WARNING - MALIGNANCY Chronic immunosuppression with AZASAN, a purine antimetabolite increases risk of malignancy in humans. Reports of malignancy include post-transplant lymphoma and hepatosplenic T-cell lymphoma (HSTCL) in patients with inflammatory bowel disease. Physicians using this drug should be very familiar with this risk as well as with the mutagenic potential to both men and women and with possible hematologic toxicities.
Physicians should inform patients of the risk of malignancy with AZASAN ® . See WARNINGS .
🎯 Indications and Usage ▾
INDICATIONS AND USAGE: AZASAN is indicated as an adjunct for the prevention of rejection in renal homotransplantation. It is also indicated for the management of active rheumatoid arthritis to reduce signs and symptoms. Renal Homotransplantation: AZASAN is indicated as an adjunct for the prevention of rejection in renal homotransplantation.
Experience with over 16,000 transplants shows a 5-year patient survival of 35% to 55%, but this is dependent on donor, match for HLA antigens, anti-donor or anti-B-cell alloantigen antibody, and other variables. The effect of AZASAN on these variables has not been tested in controlled trials. Rheumatoid Arthritis: AZASAN is indicated for the treatment of active rheumatoid arthritis (RA) to reduce signs and symptoms.
Aspirin, non-steroidal anti-inflammatory drugs and/or low dose glucocorticoids may be continued during treatment with AZASAN. The combined use of AZASAN with disease modifying anti-rheumatic drugs (DMARDs) has not been studied for either added benefit or unexpected adverse effects. The use of AZASAN with these agents cannot be recommended.
⏱️ Dosage and Administration ▾
DOSAGE AND ADMINISTRATION: Renal Homotransplantation: The dose of AZASAN required to prevent rejection and minimize toxicity will vary with individual patients; this necessitates careful management. The initial dose is usually 3 to 5 mg/kg daily, beginning at the time of transplant. AZASAN is usually given as a single daily dose on the day of, and in a minority of cases 1 to 3 days before, transplantation.
Dose reduction to maintenance levels of 1 to 3 mg/kg daily is usually possible. The dose of AZASAN should not be increased to toxic levels because of threatened rejection. Discontinuation may be necessary for severe hematologic or other toxicity, even if rejection of the homograft may be a consequence of drug withdrawal.
Rheumatoid Arthritis: AZASAN is usually given on a daily basis. The initial dose should be approximately 1.0 mg/kg (50 to 100 mg) given as a single dose or on a twice-daily schedule. The dose may be increased, beginning at 6 to 8 weeks and thereafter by steps at 4-week intervals, if there are no serious toxicities and if initial response is unsatisfactory.
Dose increments should be 0.5 mg/kg daily, up to a maximum dose of 2.5 mg/kg per day. Therapeutic response occurs after several weeks of treatment, usually 6 to 8; an adequate trial should be a minimum of 12 weeks. Patients not improved after 12 weeks can be considered refractory.
AZASAN may be continued long-term in patients with clinical response, but patients should be monitored carefully, and gradual dosage reduction should be attempted to reduce risk of toxicities. Maintenance therapy should be at the lowest effective dose, and the dose given can be lowered decrementally with changes of 0.5 mg/kg or approximately 25 mg daily every 4 weeks while other therapy is kept constant. The optimum duration of maintenance AZASAN has not been determined.
AZASAN can be discontinued abruptly, but delayed effects are possible. Patients with TPMT and/or NUDT15 Deficiency Consider testing for TPMT and NUDT15 deficiency in patients who experience severe bone marrow toxicities. Early drug discontinuation may be considered in patients with abnormal CBC results that do not respond to dose reduction (see CLINICAL PHARMACOLOGY , WARNINGS: Cytopenias , and PRECAUTIONS: Laboratory Tests ).
Homozygous deficiency in either TPMT or NUDT15 Because of the risk of increased toxicity, consider alternative therapies for patients who are known to have TPMT or NUDT15 deficiency (see CLINICAL PHARMACOLOGY , WARNINGS: Cytopenias , and PRECAUTIONS: Laboratory Tests ). Heterozygous deficiency in TPMT and/or NUDT15 Because of the risk of increased toxicity, dosage reduction is recommended in patients known to have heterozygous deficiency of TPMT or NUDT15. Patients who are heterozygous for both TPMT and NUDT15 deficiency may require more substantial dosage reductions (see CLINICAL PHARMACOLOGY , WARNINGS: Cytopenias , and PRECAUTIONS: Laboratory Tests ).
Use in Renal Dysfunction: Relatively oliguric patients, especially those with tubular necrosis in the immediate postcadaveric transplant period, may have delayed clearance of AZASAN or its metabolites, may be particularly sensitive to this drug, and are usually given lower doses. Procedures for proper handling and disposal of this immunosuppressive antimetabolite drug should be considered. Several guidelines on this subject have been published.
15-21 There is no general agreement that all of the procedures recommended in the guidelines are necessary or appropriate.
⛔ Contraindications ▾
CONTRAINDICATIONS: AZASAN should not be given to patients who have shown hypersensitivity to the drug. AZASAN should not be used for treating rheumatoid arthritis in pregnant women. Patients with rheumatoid arthritis previously treated with alkylating agents (cyclophosphamide, chlorambucil, melphalan, or others) may have a prohibitive risk of malignancy if treated with AZASAN.
⚠️ Warnings ▾
WARNINGS: Malignancy Patients receiving immunosuppressants, including AZASAN, are at increased risk of developing lymphoma and other malignancies, particularly of the skin. Physicians should inform patients of the risk of malignancy with AZASAN. As usual for patients with increased risk for skin cancer, exposure to sunlight and ultraviolet light should be limited by wearing protective clothing and using a sunscreen with a high protection factor.
Post-transplant Renal transplant patients are known to have an increased risk of malignancy, predominantly skin cancer and reticulum cell or lymphomatous tumors. The risk of post-transplant lymphomas may be increased in patients who receive aggressive treatment with immunosuppressive drugs, including AZASAN. Therefore, immunosuppressive drug therapy should be maintained at the lowest effective levels.
Rheumatoid Arthritis Information is available on the risk of malignancy with the use of AZASAN in rheumatoid arthritis (see ADVERSE REACTIONS ). It has not been possible to define the precise risk of malignancy due to AZASAN. The data suggest the risk may be elevated in patients with rheumatoid arthritis, though lower than for renal transplant patients.
However, acute myelogenous leukemia as well as solid tumors have been reported in patients with rheumatoid arthritis who have received AZASAN. Inflammatory Bowel Disease Postmarketing cases of hepatosplenic T-cell lymphoma (HSTCL), a rare type of T-cell lymphoma, have been reported in patients treated with AZASAN. These cases have had a very aggressive disease course and have been fatal.
The majority of reported cases have occurred in patients with Crohn’s disease or ulcerative colitis and the majority were in adolescent and young adult males. Some of the patients were treated with AZASAN as monotherapy and some had received concomitant treatment with a TNFα blocker at or prior to diagnosis. The safety and efficacy of AZASAN for the treatment of Crohn’s disease and ulcerative colitis have not been established.
Cytopenias Severe leukopenia, thrombocytopenia, anemias including macrocytic anemia, and/or pancytopenia may occur in patients being treated with AZASAN. Severe bone marrow suppression may also occur. Hematologic toxicities are dose-related and may be more severe in renal transplant patients whose homograft is undergoing rejection.
It is suggested that patients on AZASAN have complete blood counts, including platelet counts, weekly during the first month, twice monthly for the second and third months of treatment, then monthly or more frequently if dosage alterations or other therapy changes are necessary. Delayed hematologic suppression may occur. Prompt reduction in dosage or temporary withdrawal of the drug may be necessary if there is a rapid fall in or persistently low leukocyte count, or other evidence of bone marrow depression.
Leukopenia does not correlate with therapeutic effect; therefore, the dose should not be increased intentionally to lower the white blood cell count. TPMT or NUDT15 Deficiency Patients with thiopurine S-methyl transferase (TPMT) or nucleotide diphosphatase (NUDT15) deficiency may be at an increased risk of severe and life-threatening myelotoxicity if receiving conventional doses of AZASAN (see CLINICAL PHARMACOLOGY ). Death associated with pancytopenia has been reported in patients with absent TPMT activity receiving azathioprine.
In patients with severe myelosuppression, consider evaluation for TPMT and NUDT15 deficiency (see PRECAUTIONS: Laboratory Tests ). Consider alternative therapy in patients with homozygous TPMT or NUDT15 deficiency and reduced dosages in patients with heterozygous deficiency (see DOSAGE AND ADMINISTRATION ). Serious Infections Patients receiving immunosuppressants, including AZASAN, 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 outcom…
🤒 Adverse Reactions ▾
ADVERSE REACTIONS: The principal and potentially serious toxic effects of AZASAN are hematologic and gastrointestinal. The risks of secondary infection and malignancy are also significant (see WARNINGS ). The frequency and severity of adverse reactions depend on the dose and duration of AZASAN as well as on the patient’s underlying disease or concomitant therapies.
The incidence of hematologic toxicities and neoplasia encountered in groups of renal homograft recipients is significantly higher than that in studies employing AZASAN for rheumatoid arthritis. The relative incidences in clinical studies are summarized below: Toxicity Renal Homograft Rheumatoid Arthritis Leukopenia (any degree) >50% 28% <2500 cells/mm 3 16% 5.3% Infections 20% <1% Neoplasia * Lymphoma 0.5% Others 2.8% *Data on the rate and risk of neoplasia among persons with rheumatoid arthritis treated with azathioprine are limited.
The incidence of lymphoproliferative disease in patients with RA appears to be significantly higher than that in the general population. In one completed study, the rate of lymphoproliferative disease in RA patients receiving higher than recommended doses of azathioprine (5 mg/kg per day) was 1.8 cases per 1000 patient-years of follow-up, compared with 0.8 cases per 1000 patient-years of follow-up in those not receiving azathioprine. However, the proportion of the increased risk attributable to the azathioprine dosage or to other therapies (i.e., alkylating agents) received by patients treated with azathioprine cannot be determined.
Hematologic: Leukopenia and/or thrombocytopenia are dose-dependent and may occur late in the course of therapy with AZASAN. Dose reduction or temporary withdrawal may result in reversal of these toxicities. Infection may occur as a secondary manifestation of bone marrow suppression or leukopenia, but the incidence of infection in renal homotransplantation is 30 to 60 times that in rheumatoid arthritis.
Anemias, including macrocytic anemia, and/or bleeding have been reported. Patients with low or absent TPMT or NUDT15 activity are at increased risk for severe, life-threatening myelosuppression from AZASAN (see CLINICAL PHARMACOLOGY , WARNINGS: Cytopenias , and PRECAUTIONS , Laboratory Tests , DOSAGE AND ADMINISTRATION ). Gastrointestinal: Nausea and vomiting may occur within the first few months of therapy with AZASAN, and occurred in approximately 12% of 676 rheumatoid arthritis patients.
The frequency of gastric disturbance often can be reduced by administration of the drug in divided doses and/or after meals. However, in some patients, nausea and vomiting may be severe and may be accompanied by symptoms such as diarrhea, fever, malaise, and myalgias (see PRECAUTIONS ). Vomiting with abdominal pain may occur rarely with a hypersensitivity pancreatitis.
Hepatotoxicity manifest by elevation of serum alkaline phosphatase, bilirubin, and/or serum transaminases is known to occur following azathioprine use, primarily in allograft recipients. Hepatotoxicity has been uncommon (less than 1%) in rheumatoid arthritis patients. Hepatotoxicity following transplantation most often occurs within 6 months of transplantation and is generally reversible after interruption of AZASAN.
A rare, but life-threatening hepatic veno-occlusive disease associated with chronic administration of azathioprine has been described in transplant patients and in one patient receiving AZASAN for panuveitis. 11, 12, 13 Periodic measurement of serum transaminases, alkaline phosphatase, and bilirubin is indicated for early detection of hepatotoxicity. If hepatic veno-occlusive disease is clinically suspected, AZASAN should be permanently withdrawn.
Others: Additional side effects of low frequency have been reported. These include skin rashes, alopecia, fever, arthralgias, diarrhea, steatorrhea, negative nitrogen balance, reversible interstitial pneumonitis, hepatosplenic T-cell lymphoma (see Warnings - Malignancy ), and Sweet’s Syndrome (acute fe…
🆘 Overdosage ▾
OVERDOSAGE: The oral LD 50 s for single doses of AZASAN in mice and rats are 2500 mg/kg and 400 mg/kg, respectively. Very large doses of this antimetabolite may lead to marrow hypoplasia, bleeding, infection, and death. About 30% of AZASAN is bound to serum proteins, but approximately 45% is removed during an 8-hour hemodialysis.
14 A single case has been reported of a renal transplant patient who ingested a single dose of 7500 mg AZASAN. The immediate toxic reactions were nausea, vomiting, and diarrhea, followed by mild leukopenia and mild abnormalities in liver function. The white blood cell count, SGOT, and bilirubin returned to normal 6 days after the overdose.
🧬 Clinical Pharmacology ▾
CLINICAL PHARMACOLOGY: Azathioprine is well absorbed following oral administration. Maximum serum radioactivity occurs at 1 to 2 hours after oral 35 S-azathioprine and decays with a half-life of 5 hours. This is not an estimate of the half-life of azathioprine itself, but is the decay rate for all 35 S-containing metabolites of the drug.
Because of extensive metabolism, only a fraction of the radioactivity is present as azathioprine. Usual doses produce blood levels of azathioprine, and of mercaptopurine derived from it, which are low (<1 mcg/mL). Blood levels are of little predictive value for therapy since the magnitude and duration of clinical effects correlate with thiopurine nucleotide levels in tissues rather than with plasma drug levels.
Azathioprine and mercaptopurine are moderately bound to serum proteins (30%) and are partially dialyzable. See OVERDOSAGE . Azathioprine is metabolized to 6-mercaptopurine (6-MP).
Both compounds are rapidly eliminated from blood and are oxidized or methylated in erythrocytes and liver; no azathioprine or mercaptopurine is detectable in urine after 8 hours. Activation of 6-mercaptopurine occurs via hypoxanthine-guanine phosphoribosyltransferase (HGPRT) and a series of multi-enzymatic processes involving kinases to form 6-thioguanine nucleotides (6-TGNs) as major metabolites. The cytotoxicity of azathioprine is due, in part, to the incorporation of 6-TGN into DNA.
6-MP undergoes two major inactivation routes. One is thiol methylation, which is catalyzed by the enzyme thiopurine S-methyltransferase (TPMT), to form the inactive metabolite methyl-6-MP (6-MeMP). Another inactivation pathway is oxidation, which is catalyzed by xanthine oxidase (XO) to form 6-thiouric acid.
The nucleotide diphosphatase (NUDT15) enzyme is involved in conversion of the 6-TGNs to inactive 6-TG monophosphates. TPMT activity correlates inversely with 6-TGN levels in erythrocytes and presumably other hematopoietic tissues, since these cells have negligible xanthine oxidase (involved in the other inactivation pathway) activities. Genetic polymorphisms influence TPMT and NUDT15 activity.
Several published studies indicate that patients with reduced TPMT or NUDT15 activity receiving usual doses of 6-MP or azathioprine, accumulate excessive cellular concentrations of active 6-TGNs, and are at higher risk for severe myelosupression. Because of the risk of toxicity, patients with TPMT or NUDT15 deficiency require alternative therapy or dose modification (see DOSAGE AND ADMINISTRATION ). Approximately 0.3% (1:300) of patients of European or African ancestry have two loss-of-function alleles of the TPMT gene and have little or no TPMT activity (homozygous deficient or poor metabolizers), and approximately 10% of patients have one loss-of-function TPMT allele leading to intermediate TPMT activity (heterozygous deficient or intermediate metabolizers).
The TPMT*2, TPMT*3A, and TPMT*3C alleles account for about 95% of individuals with reduced levels of TPMT activity. NUDT15 deficiency is detected in <1% of patients of European or African ancestry. Among patients of East Asian ancestry (i.e., Chinese, Japanese, Vietnamese), 2% have two loss-of-function alleles of the NUDT15 gene, and approximately 21% have one loss-of-function allele.
The p.R139C variant of NUDT15 (present on the *2 and *3 alleles) is the most commonly observed, but other less common loss-of-function NUDT15 alleles have been observed. Inhibition of xanthine oxidase (XO) may cause increased plasma concentrations of azathioprine or its metabolites leading to toxicity (see PRECAUTIONS: Drug Interactions ). Proportions of metabolites are different in individual patients, and this presumably accounts for variable magnitude and duration of drug effects.
Renal clearance is probably not important in predicting biological effectiveness or toxicities, although dose reduction is practiced in patients with poor renal function. Homograft Survival: The use of azathioprine for…
📦 How Supplied / Storage and Handling ▾
HOW SUPPLIED: AZASAN Tablets, USP are available in: 75 mg, triangle-shaped, yellow, scored tablets, debossed with “75 mg” on one side, and “N” on the other side. 100 count bottles (NDC 65649-231-41) 100 mg, diamond-shaped, yellow, scored tablets, debossed with “100 mg” on one side, and “N” on the other side. 100 count bottles (NDC 65649-241-41) Store at 20° to 25°C (68° to 77°F) [see USP Controlled Room Temperature].
Store in a dry place and protect from light. Dispense in a tight, light-resistant container as defined in the USP.
📋 Description ▾
DESCRIPTION: AZASAN ® (azathioprine), an immunosuppressive antimetabolite, is available in tablet form for oral administration. Each scored tablet contains 75 mg or 100 mg azathioprine and the inactive ingredients lactose monohydrate, pregelatinized starch, povidone, corn starch, magnesium stearate, and stearic acid. Azathioprine is chemically 6-[(1-methyl-4-nitro-1 H-imidazol-5-yl)thio]-1 H-purine.
The structural formula of azathioprine is: It is an imidazolyl derivative of 6-mercaptopurine and many of its biological effects are similar to those of the parent compound. Azathioprine is insoluble in water, but may be dissolved with addition of one molar equivalent of alkali. Azathioprine is stable in solution at neutral or acid pH but hydrolysis to mercaptopurine occurs in excess sodium hydroxide (0.1N), especially on warming.
Conversion to mercaptopurine also occurs in the presence of sulfhydryl compounds such as cysteine, glutathione, and hydrogen sulfide. chem structure