Primarily non-CYP metabolizm. Not inhibitor or inducer of CYP3A4 or 2C9 in clinical use. However, side effects such as nausea, anorexia and vomiting may be potentially porphyrinogenic through reduction in caloric intake.

Cytarabine (cytosine arabinoside) is a synthetic pyrimidine nucleoside analog.

Cytarabine is an antimetabolite antineoplastic agent used mainly in the treatment of leukemia, especially acute non-lymphoblastic leukemia. Administered intravenously by rapid injection or continuous infusion, or by subcutaneous or intrathecal injection. Common adverse reactions of cytarabine that can be confused with an acute porphyric attack are nausea, vomiting, diarrhoea and myalgia. Side effects such as nausea, anorexia and vomiting may be potentially porphyrinogenic through reduction in caloric intake.

Cytarabine is metabolized to uridinearbinoside by hepatic, gastrointestinal and leucocyte deaminases. After entry into leucemic cells cytarabine undergoes phosphorylations forming the cytotoxic cytarabine triphosphate. Found to be a substrate of CYP3A4 by Colburn et al (2004), and also found to be an inhibitor of CYP3A4, but the authors determined that the inhibition was not of clinical significance. Baumhakel (2001) found no inhibitory effect of cytarabine on CYP3A4 in human liver microsomes.

Used uneventfully in the treatment of acute myelogenous leukemia in AIP woman (Wehmeimer, 1987). Used uneventfully in the treatment of acute lymphoblastic leukemia in PV woman (Samuels, 1984).