Mercaptopurine metabolite results in clinical gastroenterology practice.

Abstract

BACKGROUND:

Azathioprine (AZA) and its active metabolite mercaptopurine (MP) are frequently used in the management of inflammatory bowel disease. Measurement of the AZA/MP metabolites, thioguanine (TG) and methylmercaptopurine (MMP), has been suggested as a means to optimize therapy with AZA/MP in inflammatory bowel disease.

AIM:

To evaluate the results of initial AZA/MP metabolite panels sent by gastroenterologists during the first year of its widespread availability.

METHODS:

Initial AZA/MP metabolite panels sent by gastroenterologists to a single laboratory were reviewed and the metabolite panels were interpreted.

RESULTS:

Initial metabolite levels were reviewed for 9187 patients. Noncompliance was detected in 263 patients (3%) and under-dosing in 4260 patients (46%). 534 patients (6%) had levels that were consistent with preferential metabolism via the TPMT pathway. The therapeutic goal was achieved in 2444 patients (27%) and an additional 552 patients (6%) had appropriate TG levels but potential hepatotoxicity. 936 patients (10%) had potential TPMT deficiency, and 58 patients (1%) had potential TPMT absence and were at risk for leukopenia. 140 patients (2%) had too high a dose.

CONCLUSIONS:

Measurement of AZA/MP metabolites can be used by practising gastroenterologists to identify potential reasons for nonresponse to AZA or MP, and to identify patients at risk for certain drug-related toxicities.

• Authors: R S Bloomfeld, J E Onken
• Journal: Alimentary pharmacology & therapeutics (Aliment Pharmacol Ther) Vol. 17 Issue 1 Pg. 69-73 (Jan 2003) ISSN: 0269-2813 [Print] England
• PMID: 12492734 (Publication Type: Journal Article)

Chemical References

• 6-methylthiopurine
• Mercaptopurine
• Thioguanine
• Azathioprine

Topics

• Azathioprine (metabolism)
• Humans
• Inflammatory Bowel Diseases (drug therapy, metabolism)
• Mercaptopurine (analogs & derivatives, metabolism, therapeutic use)
• Patient Compliance
• Risk Factors
• Thioguanine (metabolism)