Research Article

Usefulness of Measuring Thiopurine Metabolites in Children with Inflammatory Bowel Disease and Autoimmunological Hepatitis, Treated with Azathioprine

Table 3

Metabolite levels. Mean standard deviations and the range of values of 6-thioguanine (6-TGN), 6-methylmercaptopurine (6-MMPN), measured in pmol/ erythrocytes.

6-TGN levels (all subjects)6-MMPN levels (all subjects)Interpretation

Mean level:
Within range 41% (25/61)Within rangeTherapeutic optimum
Below range 16% (10/61)Within rangeInsufficient dose
Above range 43%(26/61)Within rangePotential TPMT deficiency (potential bone marrow toxicity)
Undetectable 7 subjectsUndetectableNonadherence

6-MMP: methylmercaptopurine; 6-TGN: 6-thioguanine; TPMT: thiopurine S-methyltransferase.