Fluoroquinolones

Question 1

Fluoroquinolones (aka quinolone) - indications

Answer 1

1) Urinary tract infection (UTI) (mostly Gram-negative organisms).
2) Severe gastroenteritis (e.g. due to Shigella, Campylobacter).
3) Lower respiratory tract infection (LRTI) (Gram-positive and Gram-negative organisms; therefore moxifloxacin or levofloxacin preferred).

Question 2

Fluoroquinolones (aka quinolone) - examples

Answer 2

ciprofloxacin

moxifloxacin

levofloxacin

Question 3

Fluoroquinolones (aka quinolone) - MOA

Answer 3

Quinolones kill bacteria by inhibiting DNA synthesis (bactericidal)

Question 4

Fluoroquinolones (aka quinolone) - adverse effects

Answer 4

Generally well tolerated although they can cause:

1) GI upset (including nausea and diarrhoea)
2) immediate and delayed hypersensitivity reactions - rashes and anaphylaxis
3) neurological effects (lowering of the seizure threshold and hallucinations)
4) inflammation and rupture of muscle tendons.
5) prolong QT interval and therefore increase risk of arrhythmias (especially moxifloxacin)
6) C. difficile colitis - can acclerate to perforation and death

Question 5

Fluoroquinolones (aka quinolone) - avoid use in patients with…

Answer 5

those with increased risk of adverse effects

1) seizures
2) children

those with risk factors for
3) QT prolongation (e.g.- cardiac disease of electrolyte disturbances)

Question 6

Fluoroquinolones (aka quinolone) - interactions

Answer 6

1) Drugs containing divalent cations (e.g. calcium, antacids)
2) Theophylline
3) NSAIDs
4) Prednisolone

5) Drugs that prolong the QT interval or cause arrhythmias:
- amiodarone
- antipsychotics
- quinine
- macrolide antibiotics
- SSRIs.