UTI Flashcards
1
Q
Nitrofurantoin
Common indications
A
- Uncomplicated lower urinary tract infection
2
Q
Nitrofurantoin
MOA
A
- Nitrofurantoin is metabolised (reduced) in bacterial cells by nitrofuran reductase. Its active metabolite damages bacterial DNA and causes cell death (bactericidal effect)
- Nitrofurantoin is active against the G-ve and G+ organisms that commonly cause UTI
- Bacteria with reduced reductase activity are resistant to nitrofurantoin
- Some organisms that are less commonly cause UTI are resistant to nitrofurantoin
3
Q
Nitrofurantoin
Adverse effect
A
- GI upset and hypersensitivity
- Nitrofurantoin specifically can turn urine dark yellow or brown
- Less commonly, it may cause chronic pulmonary reactions (fibrosis), hepatitis and peripheral neuropathy
- Haemolytic anaemia may occur because immature red blood cells are unable to mop up nitrofurantoin-stimulated superoxides which damage red blood cells
4
Q
Nitrofurantoin
Warnings
A
- Nitrofurantoin should not be prescribed for pregnant women towards term
- Or for babies in the first 3 months of life
- It is contraindicated in patients with renal impairment, as impaired excretion increases toxicity and reduces efficacy due to lower urinary drug concentrations
- Caution is required when using nitrofurantoin for long term prevention of UTI’s as chronic use increases the risk of adverse effects, particularly in the elderly patients
5
Q
Nitrofurantoin
Communication
A
- Nitrofurantoin should be taken with food to minimise the GI effects
- Allergies
- Urine colour may change to brown during treatment, this is harmless and temporary
- Pins and needles or breathlessness, they should seek medical help
6
Q
Nitrofurantoin
Monitoring
A
- Treatment for acute UTI is determined by resolution of symptoms and less commonly, by ensuring sterility of urine on repeat culture
- Success in preventing recurrent UTI is determined by comparing UTI frequency before and during prophylaxis
7
Q
Trimethoprim
Common indications
A
- UTI
- Co-trimoxazole- pneumocystis pneumonia
8
Q
Trimethoprim
MOA
A
- Bacteria make folate which is essential for DNA synthesis
- Trimethoprim inhibits bacterial folate synthesis, slowing bacterial growth (bacteriostatic)
- It has a broad spectrum of action against G+ and G- bacteria, particularly enterobacteria, e.g. E.coli
- However, it’s clinical utility is reduced by widespread bacterial resistance
- MOA of resistance include reduced intracellular antibiotic accumulation and reduced sensitivity of target enzymes
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9
Q
Trimethoprim
Adverse effects
A
- Trimethoprim most commonly causes GI upset (N&V, sore mouth) and skin rash, severe hypersensitivity- including anaphylaxis
- Haematological disorders- megaloblastic anaemia, leucopenia and thrombocytopenia
- Hyperkalaemia and elevation of serum creatinine
10
Q
Trimethoprim
Warnings
A
- First trimester of pregnancy because as a folate antagonist, it is associated with increased risk of fetal abnormalities
- People with folate deficiencies who are more susceptible to haematological effects
- Less suitable for renal impairment
- Neonates, the elderly and people with HIV infections
11
Q
Trimethoprim
Interactions
A
- Pottasium-elevating drugs- e.g. aldosterone antagonists, ACEI and ARBs = increased risk of hyperkalaemia
- Folate antagoinsts- MTX
- Drugs that increase folate metabolism- increase risk of adverse haematological effects
- Trimethoprim enhances the anticoagulation effect of warfarin by killing normal gut flora that synthesise Vit K
12
Q
Trimethoprim
Communication
A
- Allergies
- Long-term treatment, FBC monitoring will be useful
