{"6-mercaptopurine can be affected by a patient's TPMT and NUDT15 phenotype. This patient is predicted to be a NUDT15 poor metabolizer and is at high risk for life threatening myelosuppression with normal doses of 6-mercaptopurine and should receive greatly reduced doses. Initiate dose at 10 mg/m2/day and adjust dose based on myelosuppression and disease-specific guidelines. Allow 4-6 weeks to reach steady state after each dose adjustment. If myelosuppression occurs, emphasis should be on reducing mercaptopurine over other agents. For non-malignant conditions, consider alternative non-thiopurine immunosuppressant therapy. However, TPMT phenotype could not be assigned based on genotyping performed. 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. If thiopurines are required and TPMT status is unknown, monitor closely for toxicity. Please consult a clinical pharmacist for more information."}