Tretinoin is one of a group of drugs called retinoids that are similar to vitamin A. It is not a chemotherapy drug, but you may have it along with chemotherapy to treat a type of acute myeloid leukemia called promyelocytic leukemia. Tretinoin is also called all-trans-retinoic acid (ATRA) and its brand name is CA Atra.ATRA is used to treat acute promyelocytic leukemia (APL, APML). Retin-A is another brand name for Tretinoin/ All-trans Retinoic Acid.