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 topoisomerase II (DNA gyrase) and topoisomerase IV

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


  • Quinolones should generally be avoided in women who are pregnant or breastfeeding
  • Avoid in G6PD