Start with reduced doses (50% to 80% of normal dose) if normal starting dose is ≥ 40-60 mg/m2/day (e.g., 20-48 mg/m2/day) and adjust doses of thioguanine based on degree of myelosuppression and disease-specific guidelines. Allow 2-4 weeks to reach steady-state after each dose adjustment. If myelosuppression occurs, and depending on other therapy, emphasis should be on reducing thioguanine over other agents (PMID 20354201, 11037857).