Sulfamethoxazole Sodium is a broad-spectrum bacteriostatic sulfonamide antibiotic belonging to the sulfanilamide family. It was first synthesized in 1957 by Shionogi Inc. in Japan, launched as Sinomin by Shionogi Inc. in 1959, and introduced to the US in 1961. Sulfamethoxazole is normally given in combination with Trimethoprim, a dihydrofolate reductase inhibitor, which inhibits the reduction of dihydrofolic acid to tetrahydrofolic acid. Studies have shown that bacterial resistance develops more slowly with the combination of the two compounds than with either Trimethoprim or Sulfamethoxazole alone.
It is effective against bacteria causing urinary tract infections, bronchitis and prostatitis.