Brequinar
Brequinar is a drug that acts as a potent and selective inhibitor of the enzyme dihydroorotate dehydrogenase. It blocks synthesis of pyrimidine based nucleotides in the body and so inhibits cell growth. It has been investigated as an immunosuppressant for preventing rejection after organ transplant and also as an anti-cancer drug, but was not accepted for medical use in either application largely due to its narrow therapeutic dose range and severe side effects when dosed inappropriately. However it continues to be researched both as part of a potential combination therapy for some cancers, or alternatively as an antiparasitic, or antiviral drug.
