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Thiopurine metabolite measurement leads to changes in management of inflammatory bowel disease
Author(s) -
Kennedy N. A.,
Asser T. L.,
Mountifield R. E.,
Doogue M. P.,
Andrews J. M.,
Bampton P. A.
Publication year - 2013
Publication title -
internal medicine journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.596
H-Index - 70
eISSN - 1445-5994
pISSN - 1444-0903
DOI - 10.1111/j.1445-5994.2012.02936.x
Subject(s) - thiopurine methyltransferase , medicine , azathioprine , inflammatory bowel disease , context (archaeology) , metabolite , adverse effect , allopurinol , pharmacology , gastroenterology , disease , paleontology , biology
Background The thiopurines azathioprine and 6‐mercaptopurine are recommended for maintenance of remission in inflammatory bowel disease ( IBD ). Measurement of concentrations of the metabolites 6‐thioguanine nucleotide and 6‐methylmercaptopurine helps delineate interindividual variation in metabolism that may underlie variability in efficacy and toxicity. Aims We aimed to perform a retrospective observational study to determine the utility of thiopurine metabolite testing following its introduction into S outh A ustralia. Methods All patients having thiopurine metabolite tests done at F linders M edical C entre between N ovember 2008 and J anuary 2010 were identified. Case notes of patients with testing done in the context of treatment for IBD were interrogated to determine the reason for testing, clinical context and outcome. Results One hundred and fifty‐one patients were identified with thiopurine metabolite testing for IBD with 157 testing episodes. Eighty (51.0%) had testing done for flare or inefficacy, 18 (11.5%) for adverse effects, 5 (3.2%) for a combination of inefficacy and adverse effects, and 54 (34.4%) for routine or other reasons. Testing was followed by improved outcomes of increased efficacy, reduced toxicity or change to alternative therapy in 55.0% of the inefficacy/flare group, 27.8% of the suspected adverse reaction group, 60.0% of the combination group, and 13.0% of the routine/other group. Allopurinol was used as cotherapy in 16 patients and led to marked improvements in metabolite concentrations. Conclusions Thiopurine metabolite testing has quickly become established in S outh A ustralia. When used for inefficacy or adverse effects, it often leads to improved outcomes. Prospective studies are needed to determine whether routine testing to guide dosing is of benefit.