Trimethoprim

Please note: This is for information only.

Refer to local guidelines for treatment recommendations


  • A diaminopyrmidine antibiotic.
  • Bacteriostatic.
  • Folate antagonist – long term use can cause blood disorders.
  • Usual adult treatment dose: 200mg twelve hourly orally.
  • Dosage adjustment necessary in renal impairment.
  • Reaches high concentrations in the lungs, kidneys and cerebrospinal fluid.
  • Contraindicated in pregnancy.
  • No IV preparation available.

Main indications:

  • First line for uncomplicated urinary tract infections
  • Active against most strains of:
  • Staphylococcus aureus – including MRSA
  • Escherichia coli
  • Klebsiella spp
  • Coliforms

Not active against most strains of:

  • Anaerobes
  • Strep pneumoniae