Please consult your physician before taking any medication. Bactrim generic 400mg 20 Tabs - sulfamethoxazole & trimethoprim Generic Name: sulfamethoxazole and trimethoprim (sul fa meth OX a zole and trye METH oh prim) Brand Names: Bactrim, Bactrim DS, Bactrim Pediatric, Bethaprim, Bethaprim Pediatric, Cotrim, Cotrim DS, Cotrim Pediatric, Septra, Septra DS, Sulfatrim, Sulfatrim Pediatric, Sulfatrim Suspension, Uroplus, Uroplus DS What is sulfamethoxazole and trimethoprim? Sulfamethoxazole and trimethoprim are both antibiotics that treat different types of bacterial infections. Sulfamethoxazole and trimethoprim fight bacteria in your body. Sulfamethoxazole and trimethoprim is used to treat infections such as urinary tract infections, bronchitis, ear infections (otitis), traveler`s diarrhea, and Pneumocystis carinii pneumonia. Sulfamethoxazole and trimethoprim may also be used for purposes other than those listed in this medication guide.