Bactrim and Bactrim DS contain a combination of two antibiotics, sulfamethoxazole and trimethoprim, that treat different types of infection caused by bacteria. Bactrim DS (double strength) tablets are twice as strong as Bactrim tablets. Bactrim is available in tablets in two strengths; 400 mg sulfamethoxazole and 80 mg trimethoprim and the DS form which means double strength, 800 mg sulfamethoxazole and 160 mg trimethoprim. Medscape - Indication-specific dosing for Bactrim, Bactrim DS, Septra, Septra DS, Cotrim, cotrimoxazole, Sulfatrim (trimethoprim, sulfamethoxazole), frequency-based adverse effects. Sulfamethoxazole and trimethoprim combination is an antibiotic. It works by eliminating the bacteria that cause many kinds of infections. This medicine will not work for colds, flu, or other virus infections. This medicine is available only with your doctor's prescription. BACTRIM DS prescription and dosage information for physicians and health care professionals. Pharmacology, adverse reactions, warnings, and BACTRIM DSside effects. Find patient medical information for Sulfamethoxazole/Trimethoprim (Bactrim, Septra, others) on WebMD including its uses, side effects and safety, interactions, pictures, warnings, and user. Bactrim DS Tablet is used in the treatment of Bacterial infections. Find Bactrim DS Tablet uses, composition, side-effects, price, substitutes, drug interactions, precautions, warnings, and expert advice.