Unusually late-onset mycophenolate mofetil-related colitis

Area of Science:

• Transplantation Medicine
• Gastroenterology
• Pharmacology

Background:

• Mycophenolate mofetil is a widely used immunosuppressant to prevent organ transplant rejection.
• Gastrointestinal complications are known side effects of mycophenolate mofetil therapy.
• Long-term immunosuppression management is crucial for transplant success.

Observation:

• A 33-year-old male heart transplant recipient presented with a 3-month history of diarrhea and weight loss.
• The patient had been on maintenance immunosuppression with mycophenolate mofetil (2 g daily) for 13 years.
• Symptoms led to acute kidney injury and metabolic acidosis, with no evidence of opportunistic infection.

Findings:

• Colonoscopy revealed erythematous and nodular mucosa.
• Histological examination of biopsy specimens confirmed mycophenolate mofetil-associated colitis.
• Discontinuation of mycophenolate mofetil resulted in resolution of diarrhea and improvement in renal function.

Implications:

• This case demonstrates that mycophenolate mofetil toxicity can manifest as serious gastrointestinal complications even after a decade of use.
• It suggests considering mycophenolate mofetil toxicity in the differential diagnosis of late-onset diarrhea in post-transplant patients, irrespective of treatment duration.
• Highlights the importance of vigilant monitoring for drug-related adverse events in long-term immunosuppressed patients.