Pharm 101: Ciprofloxacin


Fluoroquinolone antibiotic

  • Synthetic fluorinated analogue of nalidixic acid
  • Bactericidal
  • Blocks bacterial DNA synthesis by inhibiting bacterial topoisomerase II (DNA gyrase) and IV
    • Prevents normal transcription and replication
  • PO or IV administration:
    • PO 250-500mg BD
    • IV 200-300mg BD
  • Bioavailability 70%
  • Widely distributed in body fluids and tissues
  • 20-40% protein bound
  • Elimination half-life 3-5 hours
  • Renal excretion
  • CYP inhibitor
Antimicrobial activity
  • Excellent gram negative cover
    • Campylobacter, haemophilus, enterobacter, neisseria
  • Moderate gram positive cover
  • Activity against:
    • MSSA
    • Mycoplasma and Chlamydiae
    • Legionella and Mycobacterium
    • Pseudomonas
    • Anthrax
  • Clinical uses:
    • UTI
    • Bacterial gastroenteritis
    • Osteomyelitis
    • Soft tissue, intra-abdominal, respiratory infections
    • Anthrax (drug of choice for prophylaxis and treatment)
Adverse effects of fluoroquinolones
  • Gastrointestinal disturbances (nausea/vomiting/diarrhoea)
  • Rash
  • Abnormal LFTs
  • Photosensitivity
  • Growing cartilage damage (not routinely recommended for < 18 yo or pregnancy)
  • Tendonitis
  • Dose adjustment in renal failure
  • Pregnancy and < 18 year old
  • Concurrent steroid use (risk of tendon rupture)

Pharmacology 101

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MBBS (UWA) CCPU (RCE, Biliary, DVT, E-FAST, AAA) Adult/Paediatric Emergency Medicine Advanced Trainee in Melbourne, Australia. Special interests in diagnostic and procedural ultrasound, medical education, and ECG interpretation. Editor-in-chief of the LITFL ECG Library. Twitter: @rob_buttner

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