title: Hepatotoxicity associated with 6-thioguanine therapy for Crohn's disease.
abstract: 6-Thioguanine (6-TG) is a thiopurine analogue that is closely related to 6-mercaptopurine (6-MP) and azathioprine (AZA). These agents have potent cytotoxic and immunomodulatory effects and are useful in the treatment of a variety of conditions, including inflammatory bowel disease. Both 6-MP and AZA are widely used and are known to cause hepatotoxicity in a proportion of patients. 6-Thioguanine is being increasingly used in the treatment of inflammatory bowel disease but has not been reported to cause liver injury in this context. We describe a case of significant elevation of serum transaminases in a patient treated with 6-TG for a flare of Crohn's disease. We believe the temporal association of the abnormal liver enzymes in this patient, in the absence of other offending agents, argues strongly in favor of 6-TG as a cause of liver enzyme abnormalities. This case highlights the need to monitor liver enzymes in patients treated with 6-TG and identifies the need for additional research focused on the mechanism of thiopurine-induced hepatic injury.
authors.affiliation: Division of Gastroenterology, University of Washington, Seattle, Washington 98195, USA.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Rulyak
authors.forename: Michael D
authors.initials: MD
authors.lastname: Saunders
authors.forename: Scott D
authors.initials: SD
authors.lastname: Lee
mesh_terms: D000328:Adult; D000410:Alanine Transaminase / Q000627:therapeutic use; D000964:Antimetabolites, Antineoplastic / Q000009:adverse effects* / Q000627:therapeutic use; D001219:Aspartate Aminotransferases / Q000627:therapeutic use; D003424:Crohn Disease / Q000188:drug therapy* / Q000201:enzymology; D005260:Female; D006801:Humans; D008099:Liver / Q000187:drug effects*; D008111:Liver Function Tests; D015122:Mercaptopurine / Q000378:metabolism; D013866:Thioguanine / Q000009:adverse effects* / Q000627:therapeutic use
chemical_list: D000964:Antimetabolites, Antineoplastic; D015122:Mercaptopurine; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D013866:Thioguanine