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Drug Guide

Trimethoprim + Sulfamethoxazole

    Oral / IV
    Trimethoprim + Sulfamethoxazole
    Bactrim, Septrin 
  • Mechanism of Action

  • Trimethoprim inhibits the production of dihydrofolate reductase (DHFR), resulting in reduced conversion of dihydrofolic acid to active tetrahydrofolic acid - interfering with bacterial synthesis of nucleic acids. Sulfamethoxaole inhibits the production of dihydrofolate from para-aminobenzoic acid.
  • Microbiology
  • Active against most GI normal flora, the most common cause of UTI.Broad spectrum, including many aerobic gram-negative and gram-positive organisms.
  • No cover against pseudomonas.

Clinical Use

  • Indications
  • Otitis media
  • Lower respiratory tract infection
  • Genitourinary tract infections
  • Gastrointestinal infections
  • Skin / wound infections
  • Contraindications
  • Severe liver damage
  • Megaloblastic anaemia due to folate deficiency
  • Adverse Effects
  • Nausea / vomiting
  • Rash / pruritis
  • Elevated LFTs
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