What is the use of Bactrim (Trimethoprim/Sulfamethoxazole)?

From the Guidelines

Bactrim, also known as trimethoprim-sulfamethoxazole (TMP-SMX), is an antibiotic medication used to treat various bacterial infections, including urinary tract infections, with a recommended dose of one double-strength tablet (160 mg trimethoprim/800 mg sulfamethoxazole) taken twice daily for 3 days in the case of uncomplicated cystitis, as supported by the American College of Physicians 1.

Uses of Bactrim

• Urinary tract infections: Bactrim is effective against Escherichia coli, which accounts for more than 75% of all bacterial cystitis, and can be used to treat uncomplicated cystitis in women, with a treatment duration of 3 days 1.
• Respiratory infections: Although not explicitly mentioned in the provided evidence, Bactrim can be used to treat respiratory infections, such as pneumonia, in certain cases.
• Skin infections: Bactrim may be used to treat skin infections, but this is not a primary indication according to the provided evidence.
• Prophylaxis against Pneumocystis pneumonia: Bactrim is used as prophylaxis against Pneumocystis pneumonia in immunocompromised patients, but this is not directly related to the provided evidence.

Important Considerations

• Local resistance rates: The use of Bactrim for empirical treatment of acute cystitis should be guided by local resistance rates, with a threshold of 20% resistance prevalence, as recommended by the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases 1.
• Side effects: Patients should be aware of potential side effects, including skin rashes, sun sensitivity, nausea, and rarely more serious reactions like Stevens-Johnson syndrome.
• Drug interactions: Bactrim has several important drug interactions, and patients should inform their healthcare provider about other medications they are taking.
• Contraindications: Those with sulfa allergies, severe liver or kidney disease, or certain blood disorders should avoid this medication.

From the FDA Drug Label

To reduce the development of drug-resistant bacteria and maintain the effectiveness of sulfamethoxazole and trimethoprim oral suspension and other antibacterial drugs, sulfamethoxazole and trimethoprim oral suspension should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria Urinary Tract Infections For the treatment of urinary tract infections due to susceptible strains of the following organisms: Escherichia coli, Klebsiella species, Enterobacter species, Morganella morganii, Proteus mirabilis and Proteus vulgaris Acute Otitis Media For the treatment of acute otitis media in pediatric patients due to susceptible strains of Streptococcus pneumoniae or Haemophilus influenzae Acute Exacerbations of Chronic Bronchitis in Adults For the treatment of acute exacerbations of chronic bronchitis due to susceptible strains of Streptococcus pneumoniae or Haemophilus influenzae Shigellosis For the treatment of enteritis caused by susceptible strains of Shigella flexneri and Shigella sonnei Pneumocystis jirovecii Pneumonia For the treatment of documented Pneumocystis jirovecii pneumonia and for prophylaxis against P jirovecii pneumonia in individuals who are immunosuppressed and considered to be at an increased risk of developing P. jirovecii pneumonia. Traveler’s Diarrhea in Adults For the treatment of traveler’s diarrhea due to susceptible strains of enterotoxigenic E. coli.

The use of Bactrim (Trimethoprim/Sulfamethoxazole) is for the treatment of various infections, including:

• Urinary Tract Infections: due to susceptible strains of Escherichia coli, Klebsiella species, Enterobacter species, Morganella morganii, Proteus mirabilis, and Proteus vulgaris.
• Acute Otitis Media: in pediatric patients due to susceptible strains of Streptococcus pneumoniae or Haemophilus influenzae.
• Acute Exacerbations of Chronic Bronchitis: in adults due to susceptible strains of Streptococcus pneumoniae or Haemophilus influenzae.
• Shigellosis: due to susceptible strains of Shigella flexneri and Shigella sonnei.
• Pneumocystis jirovecii Pneumonia: for treatment and prophylaxis in immunosuppressed individuals.
• Traveler’s Diarrhea: in adults due to susceptible strains of enterotoxigenic E. coli 2.

From the Research

Uses of Bactrim (Trimethoprim/Sulfamethoxazole)

• Bactrim is effective in treating various infections, including:
  • Urinary tract infections (UTIs) 3, 4, 5, 6
  • Bacterial upper respiratory tract infections 3
  • Ear infections 3
  • Skin and soft-tissue infections 3
  • Septicemias 3
  • Acute and subacute bacterial endocarditis 3
  • Enteric fever 3
  • Brucellosis 3
  • Prostatitis 3
  • Gonorrhea 3
• It is also used for the treatment and prophylaxis of certain infections of the respiratory and gastrointestinal tracts 6
• Bactrim is the antimicrobial agent of choice for Pneumocystis carinii pneumonia 6
• It is useful for the treatment of Nocardia asteroides infections, either alone or in combination with other antimicrobial agents 6

Effectiveness and Tolerance

• Bactrim is well tolerated by most patients 3
• The combination of trimethoprim and sulfamethoxazole acts synergistically to inhibit the growth of certain microorganisms 3
• The cure rate with Bactrim is higher than that of other antibiotics, such as ampicillin and sulphadimidine, in the treatment of urinary infections 4

Limitations and Precautions

• High rates of resistance to trimethoprim-sulfamethoxazole preclude its use as empiric treatment of UTIs in several communities, particularly in patients who have been recently exposed to it or are at risk of infections with extended-spectrum β-lactamases (ESBLs)-producing Enterobacteriales 7
• The dosage of trimethoprim-sulfamethoxazole should be adjusted when the creatinine clearance decreases to less than 30 ml/min 6