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, CBC for cytopenias.

Stevens Johnson syndrome/toxic epidermal necrolysis, other rashes, gastrointestinal upset common, bone marrow suppression, hyperkalemia, renal failure, hepatitis, aseptic meningitis

  • ACEi - increased serum potassium level
  • Methotrexate- marrow suppression
  • Increases phenytoin
    Increases INR with warfarin
  • Pediatric strength tablets 100mg SMX/ 20 mg TMP.
  • Regular strength tablets 400mg SMX/ 80 mg TMP.
  • Double strength tablets 800 mg SMX/ 160mg TMP

Antimicrobial class: Sulfonamide - Antifolate

Average serum half life:

  • TMP (prolonged in renal failure)

    • Newborns: ~19 hours; range: 11-27 hours
    • infants 2 months to 1 year: ~4.6 hours; range: 3-6 hours.
    • Children 1-10 years: 3.7-5.5 hours.
    • Children and Adolescents >10 years: 8.19 hours
    • Adults: 6-11 hours
  • SMX: 9-12 hours, prolonged in renal failure (Adult data)

Route of Elimination: Both excreted in urine as metabolites and unchanged drug