Oxonic Acid
Oteracil is an adjunct to antineoplastic therapy, used to reduce the toxic side effects associated with chemotherapy. Approved by the European Medicines Agency (EMA) in March 2011, Oteracil is available in combination with [DB09257] and [DB09256] within the commercially available product "Teysuno". The main active ingredient in Teysuno is [DB09256], a pro-drug of [DB00544] (5-FU), which is a cytotoxic anti-metabolite drug that acts on rapidly dividing cancer cells. By mimicking a class of compounds called "pyrimidines" that are essential components of RNA and DNA, 5-FU is able to insert itself into strands of DNA and RNA, thereby halting the replication process necessary for continued cancer growth.  Oteracil's main role within Teysuno is to reduce the activity of 5-FU within normal gastrointestinal mucosa, and therefore reduce's gastrointestinal toxicity. It functions by blocking the enzyme orotate phosphoribosyltransferase (OPRT), which is involved in the production of 5-FU.