{"Azathioprine can be affected by a patient's TPMT and NUDT15 phenotype. This patient is predicted to be a possible NUDT15 intermediate metabolizer and is at risk for myelosuppression with normal doses of azathioprine. Start with reduced starting doses (30%-80% of normal dose) if normal starting dose is 2-3 mg/kg/day, (e.g., 0.6 – 2.4 mg/kg/day), and adjust doses of azathioprine based on degree of myelosuppression and disease-specific guidelines. Allow 2-4 weeks to reach steady-state after each dose adjustment. Because a TPMT genotype does not appear to have been ordered for this patient, it is not known if TPMT results would further influence the recommended dose or drug. If thiopurines are required and TPMT genotype status is unknown, consider evaluating TPMT erythrocyte activity to assess TPMT phenotype. Erythrocyte TPMT activity test results can be falsely low at diagnosis of leukemia and is unreliable in the case of recent red blood cell transfusions. Please consult a clinical pharmacist for more information."}