Sulfamethoxazole

Sulfamethoxazole is a sulfonamide bacteriostatic antibiotic with an IC50 of 2.7 μM. Sulfamethoxazole is most often used as a part of synergistic combination with trimethoprim in a 5:1 ratio in co-trimoxazole. Sulfonamides are structural analogs and competitive antagonists of para-aminobenzoic acid (PABA). They inhibit normal bacterial utilization of PABA for the synthesis of folic acid, an important metabolite in DNA synthesis.