{"6-mercaptopurine can be affected by a patient's TPMT and NUDT15 phenotype. This patient is predicted to be a TPMT poor metabolizer and NUDT15 normal metabolizer. This patient is at high risk for life threatening myelosuppression with normal doses of 6-mercaptopurine and should receive drastically reduced doses. For malignancy, reduce daily dose by 10-fold (~90% dose reduction) and reduce frequency to 3 times per week instead of daily (e.g., 10 mg/m2/day given just 3 days/week). During therapy, adjust 6-mercaptopurine doses based on degree of myelosuppression and disease-specific guidelines. It usually takes at least 4-6 weeks of stable dosing to reach steady state after each dose adjustment. If myelosuppression occurs, emphasis should be on reducing 6-mercaptopurine over other agents. For non-malignancy, consider alternative non-thiopurine immunosuppressant therapy. Please consult a clinical pharmacist for more information."}