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Two cases of thiopurine methyltransferase (TPMT) deficiency – a lucky save and a near miss with azathioprine
Author(s) -
Gardiner Sharon J.,
Gearry Richard B.,
Barclay Murray L.,
Begg Evan J.
Publication year - 2006
Publication title -
british journal of clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.216
H-Index - 146
eISSN - 1365-2125
pISSN - 0306-5251
DOI - 10.1111/j.1365-2125.2005.02474.x
Subject(s) - thiopurine methyltransferase , azathioprine , pancytopenia , medicine , gastroenterology , pediatrics , pharmacology , bone marrow , disease
Background The association between thiopurine methyltransferase (TPMT) deficiency and myelosuppression with azathioprine is well recognized. Two cases are presented that illustrate the very different outcomes that may occur with azathioprine in patients with TPMT deficiency, which affects 0.3–0.6% of caucasians. Case 1 The first patient’s TPMT deficiency was identified following hospitalization for pancytopenia attributed to azathioprine. Case 2 The second patient was identified as deficient early in treatment and myelosuppression was avoided by treating with a greatly decreased dose (25 mg per week). Conclusions Testing for TPMT ideally should be performed in every patient commencing a thiopurine drug.