Quinolones

E.g.

• nalidixic acid

  • used to treat UTI but resistance developed rapidly

• fluoroquinolones

  • ciprofloxacin

  • levofloxacin

  • gatifloxacin

Activity

• moderately active against Gram-positive

• strongly active against Gram negative

Mechanism of action

• inhibits bacterial DNA gyrases or topoisomerases

Resistance

• develops rapidly in

  • Pseudomonas

  • MRSA

  • Enterococci

• alteration of alpha-subunit of DNA gyrase

• decreased drug uptake due to changes in porins

Side Effects

• nausea

• vomiting

• dyspepsia

• abdominal pain

• diarrhoea

  • Antibiotic associated Colitis

• headache

• dizziness
• sleep disorders
• rash
  • Stevens-Johnson Syndrome
  • Toxic Epidermal Necrolysis
• pruritus

Rarer

• tendon damage
  • esp in elderly or with steroids
• anorexia
• ↑ blood urea / creatinine
• psychiatric
  • depression
  • confusion
  • hallucinations
• neurological
  • drowsiness
  • restlessness
  • asthenia
  • convulsions
    • esp if also on NSAIDs
  • paraesthesia
  • disturbances in vision
  • disturbances in taste
  • disturbances in hearing
• photosensitivity
• hypersensitivity
  • fever
  • urticaria
  • angioedema
  • arthralgia
  • myalgia
  • anaphylaxis
• blood disorders
  • eosinophilia
  • leucopenia
  • thrombocytopenia