what is bactrum for
Bactrim, Septra. SULFAMETHOXAZOLE; TRIMETHOPRIM or SMX-TMP is a combination of a sulfonamide antibiotic and a second antibiotic, trimethoprim. It is used to treat or prevent certain kinds of bacterial infections. It will not work for colds, flu, or other viral infections.actrim, Septra. SULFAMETHOXAZOLE; TRIMETHOPRIM or SMX-TMP is a combination of a sulfonamide antibiotic and a second antibiotic, trimethoprim. It is used to treat or prevent certain kinds of bacterial infections. It will not work for colds, flu, or other viral infections.