Quinolones

Quinolones are a group of antibiotics which work by inhibiting DNA synthesis and are bactericidal in nature. Examples include:

• ciprofloxacin
• levofloxacin

Mechanism of action

• inhibit topoisomeras II (DNA gyrase) and topoisomerase IV

Mechanism of resistance

• mutations to DNA gyrase, efflux pumps which reduce intracellular quinolone concentration
  Adverse effects
  
  • lower seizure threshold in patients with epilepsy
  • tendon damage (including rupture) - the risk is increased in patients also taking steroids
  • cartilage damage has been demonstrated in animal models and for this reason quinolones are generally avoided (but not necessarily contraindicated) in children
  • lengthens QT interval