Trimethoprim Flashcards
1
Q
Give some examples of drugs that contain
A
trimethoprim
Co-trimoxazole
2
Q
What are indications for use
A
- Uncomplicated UTI (1st line)
- Co-trimoxazole –> pneumocystis pneumonia in immunosuppressed (HIV)
- Broad spectrum action against gram +ve and -ve (enterobacteria - E.Coli)
3
Q
What is the mechanism of action
A
- Bacteria unable to use external sources of folate so make their own for essential functions inc DNA synthesis
- Inhibits bacterial folate synthesis slowing bacterial growth
- BACTERIOSTATIC.
4
Q
What are the side effects
A
- GI (N/V, sore mouth)
- skin rash
- hypersensitivity
- Haematological disorders (megaloblastic anaemia, leucopenia, thrombocytopenia, hyperkalaemia)
5
Q
What are the contra-indications
A
- Not prescribed in 1st trimester
- Caution in folate deficiency
- Renal impairment
- Dose reduction in HIV, neonates, elderly
6
Q
What are the interactions
A
- K elevating drugs (ALDOSTERONE ANTAGONISTS, ACEi, ARBSs) predispose to hyperkalaemia
- inc risk of SE w METHOTREXATE + PHENYTOIN
- Enhance effects of warfarin
7
Q
When is it not useful for UTIs
A
When renal impairment (excreted through kidneys) - out competed by creatinine
