Trimethoprim is an anti-bacterial used to treat and/or prevent urinary tract infections and to treat Pneumocystis carinii pneumonia (PCP) in AIDS and other high-risk patients. Combined with sulfamethoxazole, trimethoprim is used to treat infections of the airway such as chronic bronchitis and sinusitis. The combination is also used to treat ear infections, travelers' diarrhea, and shigellosis.
Trimethoprim helps prevent urine infections.As your child has been diagnosed with a problem with the urinary system, he or she is more likely to suffer urine infections than other children. Trimethoprim is a useful drug, which helps prevent urine infections. For people with HIV disease, this drug is usually given in a combination form for prevention of PCP. The combination form is trimethoprim/sulfamethoxazole, or TMP/SMX. The brand names for this drug are Bactrim and Septra. Trimethoprim is used in combination with dapsone to treat PCP. Trimethoprim alone is used at lower doses to treat upper respiratory infections and uncomplicated urinary tract infections.
Trimethoprim interferes with the body's use of folic acid. A recent study found that use of trimethoprim (and other drugs that interfere with the absorption of folic acid) during the first trimester of pregnancy increases the likelihood of birth defects, including heart defects, oral clefts, and spina bifida.
Trimethoprim alone is probably most commonly used for urinary tract infections (cystitis). It can be used both to treat a urinary tract infection and also sometimes to help prevent them (e.g. in people who keep getting this type of infection). Trimethoprim may also be used for some other bacterial infections; in this case it is often combined with another antibiotic as co-trimoxazole. There are some bacteria that are not affected by trimethoprim (resistant).
Trimethoprim is an effective antibiotic that becomes even more effective when combined with a sulfonamide (sulfa drug), such as sulfadiazine and sulfamethoxazole. The combination exhibits a greater spectrum of activity against microorganisms that cause infectious disease. The addition of trimethoprim to a sulfa drug forms a potentiated sulfa. Trimethoprim plus sulfadiazine and trimethoprim plus sulfamethoxazole are the most often-used combinations in veterinary medicine. These are similar in antibiotic function and may be used interchangeably. Trimethoprim-sulfa can kill a variety of bacteria. An additional effect of potentiated sulfa drugs is an ability to kill or suppress certain intracellular parasites, particularly Coccidia spp. and the microorganism responsible for the disease Toxoplasmosis. By itself, Trimethoprim is active against a wide range of bacteria, but it has little activity against species of bacteria such as mycoplasma and chlamydia, so would not likely be too useful in treating respiratory disease. In combination with a sulphonamide drug, Trimethoprim has a good range of activity against a wide variety of bacteria, and seems to be most useful in treating intestinal diseases caused by bacteria.