Therapeutic Drug Monitoring and Pharmacogenomics of Thiopurines in Inflammatory Bowel Disease: International Guidelines Revisited

There is substantial variability in the global TDM and pharmacogenomic practices for thiopurines in IBD. Limited recommendations for NUDT15 testing and disparities in resource availability have contributed to inconsistent clinical implementation. Future guidelines should address these gaps by integrating cost-effective pharmacogenomic strategies and incorporating alternative monitoring methods such as DNA-TG for NUDT15 variants. This review highlights the variability in the global recommendations for thiopurine TDM and pharmacogenomics. To optimize thiopurine therapy and reduce toxicity risks, future guidelines should include NUDT15 testing and consider TG, low-dose thiopurine, and allopurinol treatments.