Escherichia coli (Gram Negative Bacillus - Overall)
Trimethoprim/Sulfamethoxazole (TMP/SMX)

Trimethoprim/Sulfamethoxazole (TMP/SMX)

Low
Excellent

General Information

  • Urinary tract infections
  • Susceptible MRSA infections
  • Stenotrophomonas infections
  • Pneumocystis jirovecii pneumonia (treatment or prophylaxis)

Follow creatinine and electrolytes in patients at increased risk renal failure, hyperkalemia.

Perform appropriate culture and susceptibility tests before treatment.

Perform microscopic urinalysis and renal function tests during therapy, particularly in patients with renal impairment.

Monitor for acid-base disturbances and CBC.

Common

  • Rash
  • Urticaria
  • Loss of appetite
  • Nausea
  • Vomiting

Serious

  • Cardiogenic shock
  • Prolonged QT interval
  • Torsades de pointes
  • Ventricular tachycardia
  • Stevens-Johnson syndrome
  • Toxic epidermal necrolysis
  • Erythema multiforme
  • Hyponatremia
  • Agranulocytosis
  • Aplastic anemia
  • Neutropenia
  • Thrombocytopenia
  • Hepatic necrosis
  • Rhabdomyolysis
  • Clostridioides difficile infection
  • Anaphylaxis
  • ACEi - Increased serum potassium level
  • Increases amantadine levels
  • Decreases cyclosporine
  • Methotrexate - marrow suppression
  • Increases phenytoin
  • Increases rifampin
  • Warfarin - increases INR

Multiple drug-drug interactions

Antimicrobial class: Sulfonamide - Antifolate

Pregnancy category: C

Average serum half life: 10 hours

Biliary penetration: Moderate

CSF penetration: Therapeutic

Lung penetration: Therapeutic

Urine penetration: Therapeutic

Precautions:

  • Beers Criteria: Avoid use in elderly with CrCl <15 mL/min and reduce dose if CrCl 15-29 mL/min.
  • Avoid concomitant use with phenytoin due to increased risk of phenytoin toxicity.
  • Use caution in older adults with concomitant ACEI or ARB therapy due to risk of hyperkalemia.
  • Avoid use or use caution in patients with hepatic or renal impairment.