Letter: thiopurine blood monitoring for patients with inflammatory bowel disease

Abstract

I read with great interest, the article by Chouchana and colleagues.1 The authors summarised the current evidence examining the efficacy and dose and nondose-related toxicity of thiopurine in patients with inflammatory bowel disease (IBD). They suggested an evidence-based algorithm to help with guiding practitioners in using thiopurine for patients with IBD. They recommended monitoring of blood count regularly during therapy as myelotoxicity can happen at any time during therapy beginning from 2 weeks after introduction of thiopurine.2 In the algorithm provided, the authors recommended regular blood testing for blood cell counts and liver tests. Unfortunately, the authors did not provide any recommendations regarding how frequently the blood testing should be performed. Regular blood testing can be an obstacle in initiating and maintain thiopurine especially in children with IBD. Currently, there is no consensus regarding the frequency of blood testing for thiopurine monitoring. Several practitioners would do blood testing every week for the first 4 weeks after initiating thiopurine therapy, followed by fortnight blood testing for 1 month, then monthly blood testing for a variable duration, and then 3-month blood testing, until thiopurine is stopped. Although there is no good evidence to suggest clear benefits of thiopurine therapy after 18 months of maintaining IBD remission, it is very common for patients with IBD to be on thiopurine for 5 years.3 Continuoing blood monitoring for such a long duration can create major anxiety especially in children with IBD. Large well-designed studies are needed to address this important issue. Declaration of personal and funding interests: None.