The most commonly reported side effects of mercaptopurine include febrile neutropenia, off label use, and pyrexia, based on 22,269 FDA adverse event reports from 2004 to 2025. 5.9% of reports found the drug to be ineffective.
Percentages show how often each reaction appears relative to total reports for mercaptopurine.
These are voluntary reports and do not establish that mercaptopurine caused these reactions.
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Other drugs that appear in adverse event reports alongside mercaptopurine. Drugs flagged as a suspected cause appear in the first column. Drugs taken at the same time but not suspected appear in the second.
Also suspected
Taken alongside
Co-occurrence in adverse event reports does not establish a drug interaction. Patients often take multiple medications, and these lists reflect prescribing patterns rather than causal relationships. Consult a healthcare provider about potential drug interactions.
41.4% of mercaptopurine adverse event reports involve female patients and 43.8% involve male patients. The largest age group is adult at 46%. These figures reflect who reports side effects, not underlying risk.
Sex
Age group
Conditions and purposes for which patients were taking mercaptopurine when the adverse event was reported.
Showing 15 of 438 indications
Mercaptopurine is sold under the brand name Purixan.
An upward trend reflects increased FAERS reporting overall, not necessarily increased risk.
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