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Thiopurine-induced myelotoxicity in patients with inflammatory bowel disease: a review

Javier P Gisbert1, Fernando Gomollón

  • 1Gastroenterology Unit, Hospital Universitario de la Princesa, Madrid, Spain.

The American Journal of Gastroenterology
|June 19, 2008
PubMed
Abstract

Insights

Azathioprine (AZA) and mercaptopurine (MP) can cause myelosuppression in inflammatory bowel disease (IBD) patients. The incidence rate of AZA/MP-induced myelotoxicity is about 3% per patient-year, with severe cases and mortality risks being low.

Area of Science:

  • Gastroenterology and Hepatology
  • Pharmacology and Toxicology
  • Immunology

Background:

  • Azathioprine (AZA) and mercaptopurine (MP) are thiopurine medications commonly used in managing inflammatory bowel disease (IBD).
  • Myelosuppression, a potentially lethal adverse event, is a significant concern associated with AZA and MP therapy.

Purpose of the Study:

  • To review and quantify the incidence and risk of azathioprine/mercaptopurine-induced myelotoxicity in patients diagnosed with inflammatory bowel disease.
  • To analyze the cumulative incidence and incidence rate of myelotoxicity, including severe cases and associated mortality.

Main Methods:

  • Conducted a comprehensive bibliographical search of MEDLINE and EMBASE databases.
  • Reviewed studies that evaluated thiopurine-induced myelotoxicity in IBD patients.
  • Performed a meta-analysis to calculate the cumulative incidence and incidence rate of AZA/MP-induced myelotoxicity.

Main Results:

  • Included 66 studies involving 8,302 IBD patients; cumulative incidence of myelotoxicity was 7% (95% CI 6-8%).
  • The incidence rate of myelotoxicity was 3% per patient-year (95% CI 3-4%), with similar risks for AZA and MP.
  • Severe myelotoxicity occurred in 1.1% of patients, with a mortality risk of 0.06% (95% CI 0.02-0.17%).

Conclusions:

  • The incidence rate of myelotoxicity in IBD patients on AZA/MP is approximately 3% per patient-year, often occurring within the initial months of therapy.
  • Severe myelotoxicity and associated mortality risks are low, less than 1% and 0.1% per patient-year, respectively.
  • While myelotoxicity can occur anytime, early monitoring is crucial for timely intervention in IBD patients receiving thiopurines.

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