This phase I trial is studying the side effects and best dose of GTI-2040 and high-dose cytarabine in treating patients with refractory or relapsed acute myeloid leukemia. GTI-2040 may stop the growth of cancer cells by blocking the enzymes necessary for cancer cell growth. Drugs used in chemotherapy, such as cytarabine, use different ways to stop cancer cells from dividing so they stop growing or die. Giving GTI-2040 together with cytarabine may kill more cancer cells.