Trimethoprim
- OralTrimethoprimAlprim
Mechanism of Action
- 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.
- Pharmacology
- Higher affinity for bacterial dihydrofolate reductase than for human DHFR.
- Mostly excreted unmetabolised into urine in high concentrations, resulting in its effect directly within the bladder.
Microbiology
- Active against most GI normal flora, the most common cause of UTI.
Clinical Use
Indications
- Uncomplicated symptomatic urinary tract infection.
Contraindications
- Megaloblastic anaemia due to folate deficiency.
- Adverse Effects
- Rash / pruritis
- Nausea / vomiting
- Elevated LFTs