Pyrimethamine
Pyrimethamine is a synthetic derivative of ethyl-pyrimidine with potent antimalarial properties.  Pyrimethamine is a competitive inhibitor of dihydrofolate reductase (DHFR).  DHFR is a key enzyme in the redox cycle for production of tetrahydrofolate, a cofactor that is required for the synthesis of DNA and proteins.  This agent is often used in combination with other antimalarials for the treatment of uncomplicated falciparum malaria. (NCI04)