NCIt definition : A broad-spectrum sulfanilamide and a synthetic analog of para-aminobenzoic acid (PABA)
with antibacterial property. Sulfamethizole competes with PABA for the bacterial enzyme
dihydropteroate synthase, thereby preventing the incorporation of PABA into dihydrofolic
acid, the immediate precursor of folic acid. This leads to an inhibition of bacterial
folic acid synthesis and de novo synthesis of purines and pyrimidines, ultimately
resulting in cell growth arrest and cell death.;