Trimethoprim

• What is trimethoprim?

  Anti-folate antibiotic
• What is the pharmacology of trimethroprim?

  Target: Dihydrofolate reductase (DHFR)

  Action: Antagonist
• MOA- Trimethoprim

  Binds to & inhibits DHFR -> prevents conversion of dihydrofolate to tetrahydrofolate (THF) -> decreases purine & pyrimidine synthesis -> decreased DNA synthesis -> decreased bacteria cell growth

  Binds to bacterial DHFR with higher affinity than mammalian DHFR
• What are the indications of trimethoprim?

  Respiratory tract infections

  UTIs

  Acute diverticulitis
• What are the side effects of trimethoprim?

  Diarrhoea

  Electrolyte imbalance

  Headache
• What is the monitoring required for trimethoprim?

  Monitor blood counts with long term use OR in patients at high risk of folate deficiency