Trimethoprim Flashcards Preview

Year 3 - Therapeutics > Trimethoprim > Flashcards

Flashcards in Trimethoprim Deck (6)
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1
Q

What is co-trimazole?

A

Trimethoprim and sulfamethoxazol

2
Q

What is the method of action of trimethoprim?

A
  • Inhibits bacterial folate synthesis
  • Slows bacterial growth (bacteriostatic)
  • Bacteria are unable to use external sources of folate so need to make their own for processes like DNA synthesis
  • Broad spectrum for gram negative and gram positive bacteria esp. enterobacteria (E.coli)
  • Sulfamethoxazole also inhibits folate synthesis
3
Q

What are the indications for trimethoprim?

A
  • Uncomplicated UTI

* Treatment and prevention of pneumocystic pneumonia in immunosuppressed people (Co-trimazole)

4
Q

What are the contraindications for trimethoprim?

A
  • 1st trimester of pregnancy – due to being a folate antagonist so can cause cardiovascular defects and cleft lip in the foetus
  • Folate deficiency – caution as ↑ haematological affects
  • Renal impairment – dose ↓ due to rise in serum creatinine levels
  • Neonates – susceptible to adverse effects
  • Elderly – susceptible to adverse effects
  • HIV infection – susceptible to adverse effects
5
Q

What are the side effects of trimethoprim?

A
  • GI upset – nausea, vomiting, sore mouth
  • Skin rash and hypersensitivity – more common with sulphonamides
  • Haematological disorders e.g. megoblastic anaemia, leucopenia, thrombocytopenia – due to being a folate antagonist
  • Hyperkalaemia
6
Q

What drugs interact with trimethoprim?

A
  • Aldosterone antagonists – K+ elevating drugs
  • ACE inhibitors – K+ elevating
  • Angiotensin receptor blockers – K+ elevating
  • Methotrexate – folate antagonist
  • Phenytoin - ↑ folate metabolism so haematological effects more likely
  • Warfarin - ↑ anticoagulant effect by killing normal gut flora that synthesises Vit K

Decks in Year 3 - Therapeutics Class (72):