Co-trimoxazole is an antibiotic made up of two different antibiotics (sulfamethoxazole and trimethoprim). Sulfamethoxazole belongs to a group of medicines known as sulphonamides and trimethoprim belongs to a group of medicines known as benzylpirimidines.
It is used to prevent and treat infections caused by certain bacteria, fungi and parasites. These may include infections of the lung, urinary tract, skin and soft tissue. Bactrim works by blocking two essential steps in the growth of bacteria.