A liposomal intrathecal formulation of the antimetabolite cytarabine. As an S-phase-specific antimetabolite, cytarabine is phosphorylated by deoxycytidine kinase to a triphosphate form which competes with thymidine for incorporation into DNA; the incorporation of cytarabine triphosphate into DNA appears to inhibit DNA polymerase and so DNA synthesis, resulting in cell death. A group of enzymes involved in drug metabolism and found in high levels in the liver. These enzymes change many drugs, including anticancer drugs, into less toxic forms that are easier for the body to excrete.OR