Can Imuran (azathioprine) be given with acute pancreatitis or infection?

Azathioprine Should Be Discontinued in Patients with Acute Pancreatitis or Active Infection

Azathioprine (Imuran) should be immediately discontinued in patients with acute pancreatitis and should not be restarted, as it is a known cause of drug-induced pancreatitis. 1, 2 Similarly, azathioprine should be temporarily discontinued during active infections due to its immunosuppressive effects that can worsen infection outcomes. 1

Azathioprine and Acute Pancreatitis

Risk and Recognition

• Acute pancreatitis is a well-documented adverse effect of azathioprine therapy
• The incidence rate for acute pancreatitis among azathioprine users is approximately 1 per 659 treatment-years 3
• Risk is substantially higher in patients with Crohn's disease (4.9%) compared to other conditions such as autoimmune hepatitis (1.5%) 4
• Pancreatitis typically occurs early in treatment course, often within the first 90 days 5

Clinical Presentation and Diagnosis

• Presents with acute abdominal pain and/or severe vomiting
• Serum amylase should be measured to confirm diagnosis 1
• Pancreatitis can range from mild to severe, with some cases developing complications like pseudocysts 2

Management

• Immediate discontinuation of azathioprine is mandatory 1, 2
• Azathioprine-induced pancreatitis usually runs a benign, self-limited course once the drug is withdrawn
• Rechallenge with azathioprine is contraindicated as symptoms typically recur 6
• Consider alternative immunosuppressants:
  • Mycophenolate mofetil (MMF) is the second-line drug of choice for patients intolerant to azathioprine 1
  • 6-mercaptopurine (6-MP) or 6-thioguanine (6-TG) are alternative options 1

Azathioprine and Infection

Risk Assessment

• Azathioprine increases susceptibility to viral, bacterial, and fungal infections, especially when combined with corticosteroids 1
• Infection in elderly patients with bullous pemphigoid treated with azathioprine and prednisolone has been identified as a significant cause of mortality 1

Management During Active Infection

• Temporarily discontinue azathioprine during active infections 1
• Prompt use of appropriate antimicrobial therapy based on the type of infection:
  • For bacterial infections: targeted antibiotics based on culture results
  • For viral infections (e.g., VZV): prompt use of oral antivirals (aciclovir, valaciclovir, or famciclovir) 1

Special Considerations

• In patients with acute pancreatitis and infection, both conditions require separate management:
  • Discontinue azathioprine permanently due to pancreatitis 2
  • Treat infection with appropriate antimicrobials 1
  • Do not use prophylactic antibiotics in acute pancreatitis unless there is confirmed or strongly suspected infection 7

Monitoring and Prevention

• Weekly monitoring of full blood count (FBC) and liver function tests (LFTs) for the first 4 weeks of azathioprine therapy 1
• Continued monitoring at least every 3 months for the duration of therapy 1
• Patients should be instructed to report immediately any evidence of infection, unexpected bruising, bleeding, or jaundice 1
• Consider TPMT testing prior to starting azathioprine to identify patients at higher risk of toxicity 1

Common Pitfalls

• Failure to recognize early signs of pancreatitis (abdominal pain, vomiting)
• Attempting to rechallenge with azathioprine after an episode of drug-induced pancreatitis
• Continuing azathioprine during severe infections
• Inadequate monitoring of blood counts during therapy

Remember that while azathioprine is an effective immunosuppressant for various conditions, patient safety must be prioritized when complications like pancreatitis or infection arise.