Provider Briefing: Azasan (Azathioprine) Supply Status in 2026

Drug shortages continue to challenge clinical workflows, and Azathioprine — marketed as Azasan (Salix Pharmaceuticals/Bausch Health) and Imuran — has been among the immunosuppressants affected. This briefing provides prescribers with an up-to-date overview of the supply landscape, prescribing considerations, and practical tools for ensuring patient continuity of care.

Timeline of the Azathioprine Shortage

The supply disruptions for Azathioprine have unfolded over several phases:

• Prior years: Azathioprine tablets appeared on the ASHP drug shortage list intermittently due to increased demand. Prometheus Laboratories (a previous distributor of Imuran) cited increased demand as the primary driver.
• September 2024: Azathioprine sodium injection (100 mg vials) was added to the ASHP drug shortage list. The injectable form is used primarily in the inpatient setting for transplant patients unable to tolerate oral medications.
• 2024–2025: Hikma Pharmaceuticals maintained supply of injectable azathioprine sodium 100 mg vials, but availability remained limited at many facilities. Oral tablet supply experienced localized disruptions at retail pharmacies.
• Early 2026: The injectable shortage persists. Brand-name Azasan (75 mg and 100 mg tablets) has limited distribution due to single-source manufacturing by Salix Pharmaceuticals. Generic oral Azathioprine (25 mg and 50 mg tablets) from multiple manufacturers is generally available, though spot shortages continue to be reported.

Prescribing Implications

The shortage has several practical implications for prescribers:

Inpatient to Outpatient Transitions

When injectable Azathioprine is unavailable, patients may be transitioned to oral formulations sooner. Ensure that patients are tolerating oral intake before switching, and confirm that the outpatient pharmacy can fill the oral prescription before discharge.

Brand vs. Generic Considerations

Azasan tablets are available in 75 mg and 100 mg strengths, while generic Azathioprine is available in 25 mg and 50 mg tablets. If prescribing for a dose that doesn't align neatly with available generic strengths (e.g., 75 mg or 100 mg), consider whether dose adjustment is clinically appropriate or whether tablet splitting is feasible (generic 50 mg tablets are scored).

TPMT/NUDT15 Testing

Regardless of supply considerations, ensure TPMT and/or NUDT15 genotype or phenotype testing has been performed prior to initiating Azathioprine. Patients with low or absent enzyme activity are at greatly increased risk for severe, life-threatening myelosuppression. This is especially important when initiating therapy or switching patients between formulations.

Monitoring During Transitions

When switching patients between brand and generic, or between Azathioprine and alternative immunosuppressants, consider more frequent CBC monitoring (weekly for the first 4–8 weeks) and liver function testing to ensure therapeutic levels and detect toxicity early.

Current Availability Picture

Cost and Access Considerations

Cost can be a significant barrier to adherence, particularly for uninsured or underinsured patients:

• Brand-name Azasan: ~$340–$500 for 30 tablets (100 mg) at retail price
• Generic Azathioprine: ~$30–$70 for 30 tablets (50 mg) at retail; as low as $6–$15 with discount coupons
• Insurance: Most plans cover generic Azathioprine on a preferred generic tier ($0–$15 copay). Brand-name Azasan may require prior authorization.

For patients facing cost barriers, resources include:

• Salix Pharmaceuticals Patient Assistance Program (1-800-321-4576)
• NeedyMeds (needymeds.org) and RxAssist (rxassist.org) for PAP databases
• Discount coupon services: GoodRx, SingleCare, and others can reduce generic costs to as low as $6/month

For a patient-facing resource on savings, see How to Save Money on Azasan.

Tools and Resources for Providers

Medfinder for Providers

Medfinder for Providers allows you to check real-time pharmacy availability of Azasan and generic Azathioprine. You can direct patients to pharmacies with confirmed stock or use the tool to facilitate pharmacy transfers.

ASHP Drug Shortage Resources

The ASHP Drug Shortages Center provides the most current information on the Azathioprine sodium injection shortage, including manufacturer updates and estimated resolution dates.

Alternative Therapy References

When Azathioprine is unavailable, consider the following alternatives based on indication:

• Transplant rejection prevention: Mycophenolate Mofetil (CellCept), Tacrolimus (Prograf), Cyclosporine (Neoral)
• Rheumatoid arthritis: Methotrexate (first-line DMARD), Leflunomide, biologics (if appropriate)
• IBD (off-label): Mercaptopurine (6-MP), Methotrexate, biologic agents
• Other autoimmune: Mycophenolate, Methotrexate, Cyclosporine (condition-dependent)

For patient-facing alternative information, refer patients to Alternatives to Azasan.

Looking Ahead

The Azathioprine supply situation is expected to improve gradually through 2026 as manufacturers address production capacity and raw material sourcing. However, the injectable form may take longer to fully resolve. Prescribers should:

• Continue to prescribe generic Azathioprine when clinically appropriate (better availability and lower cost)
• Proactively discuss supply concerns with patients to reduce anxiety and improve adherence
• Use tools like Medfinder for Providers to assist patients in locating available stock
• Report shortages to the FDA Drug Shortage Staff to support national tracking efforts

Final Thoughts

Drug shortages are a systemic challenge, but proactive communication between prescribers, pharmacies, and patients can minimize the clinical impact. Azathioprine remains a cornerstone immunosuppressant, and the generic formulation is generally accessible. By staying informed and using available tools, providers can help ensure their patients maintain uninterrupted therapy.

For additional clinical resources, see our provider guides on helping patients find Azasan in stock and helping patients save money on Azasan.