Trimethoprim/Sulfamethoxazole, better know by one of it's brand names Bactrim(TM), is a two-drug combination antibiotic. It works against a very wide range of bacteria, including those that are resistant to other antibiotics, such as MRSA. Because its two components work at different points of the bacterial life cycle, they work better together than separately. It is commonly used to treat urinary tract infection, traveller's diarrhea, respiratory tract infections and cholera. It can be administered intravenously or taken orally.
Side effects are similar to other antibiotics and include nausea, diarrhea and allergy. As allergic reactions to the drug are more common than with other antibiotics, it is usually not a first choice for treatment. It should be avoided during pregnancy due to a high risk of congenital defects. It must be avoided in patients with liver or kidney dysfunction. It also has several medicine interactions.