Cytarabine (ARA-C) pharma

Ara-C is not effective when given orally, because of its deamination to the noncytotoxic ara-U by cytidine deaminase in the intestinal mucosa and liver. Given IV, it distributes throughout the body but does not penetrate the CNS in sufficient amounts to be effective against meningeal leukemia. However, it may be injected intrathecally. A new preparation that provides slow release into the CSF is also available. Ara-C undergoes extensive oxidative deamination in the body to ara-U, a pharmacologically inactive metabolite. Both ara-C and ara-U are excreted in urine.