Pharm 101: Ciprofloxacin

Class

Fluoroquinolone antibiotic


Pharmacodynamics
  • 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

Pharmacokinetics
  • 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

Precautions/contraindications
  • Dose adjustment in renal failure
  • Pregnancy and < 18 year old
  • Concurrent steroid use (risk of tendon rupture)

References

Pharm 101 700

Pharmacology 101

Top 200 drugs

MBBS (UWA) CCPU Emergency Medicine Trainee with interests in medical education, ECG interpretation, and the use of point-of-care ultrasound in the undifferentiated patient. Co-author of the LITFL ECG Library | Twitter

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