Thiopurines maintain remission and modify disease course in inflammatory bowel disease.
Use is limited by intolerance and subsequent drug withdrawal in approximately 17% of patients treated with azathioprine.
Previous case series have addressed the success rates of re-treatment with mercaptopurine in these individuals.
Dr Lees and colleagues from the United Kingdom determined the rate of tolerance when trialling mercaptopurine in azathioprine-intolerant patients and the factors predictive of success, and to perform a systematic review and meta-analysis of these data with other published data sets.
The researchers performed a retrospective observational study of 149 patients with IBD previously intolerant of azathioprine subsequently treated with mercaptopurine was performed.
|68% tolerated mercaptopurine|
|Alimentary Pharmacology & Therapeutics|
A meta-analysis was undertaken of all published studies of mercaptopurine use in azathioprine-intolerant patients.
The researchers found that mercaptopurine was tolerated by 58% of azathioprine-intolerant patients in the Edinburgh cohort.
In the meta-analysis, 68% tolerated mercaptopurine.
A higher proportion of those in the meta-analysis with GI toxicity or hepatotoxicity were able to tolerate mercaptopurine than those with flu-like illness.
The team noted that among those patients who ceased mercaptopurine for further adverse effects, 59% experienced the same adverse effect as they had with azathioprine.
Dr Lees' team concludes, "This meta-analysis shows that switching to mercaptopurine is a safe therapeutic strategy for over two-thirds of azathioprine-intolerant patients and may help optimize immunomodulatory therapy in inflammatory bowel disease."
"A trial of mercaptopurine should be attempted in IBD patients before considering thiopurine intolerance."