Based on TPMT status, start with drastically reduced doses (PMID 11037857) (reduce daily dose by 10-fold and dose thrice weekly instead of daily) and adjust doses of thioguanine based on degree of 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 thioguanine over other agents. For non-malignant conditions, consider alternative non-thiopurine immunosuppressant therapy (PMID 20354201). NUDT15 status could not be determined based on genotyping. If thiopurines are required and NUDT15 status is unknown, monitor closely for toxicity.