Vidaza and Valproic Acid Post Allogeneic Transplant for High Risk AML and MDS

Inclusion Criteria: 1. All allograft patients \> 2 years of age. 2. Patients will have one of the following malignancies: a. Patients with refractory or relapsed: acute myelogenous leukemia (AML) (including inv16, t(8;21) or t(15;17)) or high risk myelodysplastic syndrome (MDS) (defined as bone marrow blasts \> or = 5%) are eligible. Patients may be in remission at the time of entry. 3. Patients with adequate organ function and performance status criteria measured by: 1. Karnofsky score greater than or equal to 70% or Performance status of \< or = 2 by the Eastern Cooperative Oncology Group (ECOG) scale 2. Adequate liver function (bilirubin of \< 2mg/dL, serum glutamate pyruvate transaminase \< 3 \* ULN) and renal function (creatinine \< 2mg/dL) 4. Signed informed consent indicating that patients are aware of the investigational nature of this study in accordance with the regulations of Loyola University Medical Center 5. Patients must have undergone allogeneic stem cell transplant within 40-60 days before starting treatment and be self-sufficient in caloric intake along with no active graft vs. host disease Exclusion Criteria: 1. Nursing and pregnant females are excluded. 2. Active and uncontrolled infections will cause patients to be excluded. 3. Patients already receiving valproic acid or receiving other anticonvulsants will be excluded. 4. Low risk AML in complete remission 1, will not be candidates for this study. 5. Patients with an absolute neutrophil count less than 1500 will be excluded 6. Patients with platelets less than 50,000 will be excluded 7. Children less than 2 years of age will be excluded due to increased hepatotoxicity from valproic acid in this age group