What is Bactrim?

Common Brand(s): Bactrim, Septra

This medication is a combination of two antibiotics: sulfamethoxazole and trimethoprim. It is used to treat a wide variety of bacterial infections (such as middle ear, urine, respiratory, and intestinal infections). It is also used to prevent and treat a certain type of pneumonia (pneumocystis-type).

This medication should not be used in children less than 2 months of age due to the risk of serious side effects.

This medication treats only certain types of infections. It will not work for viral infections (such as flu). Unnecessary use or misuse of any antibiotic can lead to its decreased effectiveness.


  • cholera
  • typhoid fever
  • paratyphoid fever
  • gastroenteritis due to Shigella
  • isosporiasis
  • brucellosis
  • Listeria meningitis
  • pertussis
  • nocardiosis
  • chlamydial infections
  • Q fever
  • lymphogranuloma venereum
  • granuloma inguinale
  • paracoccidioidomycosis
  • toxoplasmosis prevention
  • Pneumocystis jirovecii pneumonia
  • Pneumocystis jiroveci pneumonia prevention
  • Haemophilus influenzae acute otitis media
  • Streptococcus acute otitis media
  • acute bacterial otitis media
  • bacterial endocarditis
  • sinusitis
  • bacterial pneumonia
  • chronic bronchitis with bacterial exacerbation
  • Streptococcus pneumoniae chronic bronchitis
  • Haemophilus influenzae chronic bronchitis
  • diverticulitis of gastrointestinal tract
  • Enterobacter cloacae urinary tract infection
  • E. coli urinary tract infection
  • Klebsiella urinary tract infection
  • Proteus urinary tract infection
  • Morganella morganii urinary tract infection
  • prevention of bacterial urinary tract infection
  • chronic bacterial prostatitis
  • skin and skin structure infection
  • bone infection
  • meningococcal carrier
  • Whipple's disease
  • postexposure plague prophylaxis
  • bacterial urinary tract infection
  • acquired immunodeficiency syndrome with toxoplasmosis
  • diabetic foot infection

Usage Instructions

Take this medication by mouth, as directed by your doctor, with a full glass of water (8 ounces / 240 milliliters). If stomach upset occurs, take with food or milk. Drink plenty of fluids while taking this medication to lower the unlikely risk of kidney stones forming, unless your doctor advises you otherwise. Dosage is based on your medical condition and response to treatment.

For the best effect, take this antibiotic at evenly spaced times. To help you remember, take this medication at the same time(s) every day.

Continue to take this medication until the full prescribed amount is finished, even if symptoms disappear after a few days. Stopping it too early may allow bacteria to continue to grow, which may result in a relapse of the infection.

Tell your doctor if your condition persists or worsens.


Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.