DrugFriday: Ciprofloxacin

Ciprofloxacin is an antibacterial drug belonging to the Fluoroquinolone class of antibiotics.

Mechanism of action:

It causes DNA breakdown in bacteria by inhibiting enzyme DNA gyrase

Pharmacology:

Oral bioavailability of Ciprofloxacin is 50-85%

Peak plasma time: 0.5-2.5 hours depending on immediate or extended release

Distribution:

Ciprofloxacin is distributed widely throughout body and tissue concentrations often exceed serum concentrations, especially in kidneys, gallbladder, liver, lungs, gynecologic tissue, and prostatic tissue; cerebrospinal fluid (CSF) concentration is 10% in noninflamed meninges and 14-37% in inflamed meninges; crosses placenta; enters breast milk.

Metabolism:

Ciprofloxacin is metabolized mainly in the liver.

Elimination:

40-50% excretion of Ciprofloxacin is via urine and ~30% is via stools

Indications and dosage:

1. Bone and joint infections:
   • Mild/moderate: 500 mg orally 12hrly or 400 mg IV 12hrly for ≥4-6 weeks
   • Severe/complicated: 750 mg orally 12hrly or 400 mg IV 8hrly for ≥4-6 weeks
2. Chronic prostatitis
   • Indicated for chronic bacterial prostatitis caused by Escherichia coli or Proteus mirabilis
   • Mild/moderate: 500 mg orally 12hrly or 400 mg IV 12hrly for 28 days
3. Infectious diarrhea:
   Mild/moderate/severe: 500 mg PO 12hrly for 5-7 days
4. Intra abdominal infections:
   Complicated: 500 mg PO 12hrly or 400 mg IV 12hrly for 7-14 days
5. Lower respiratory infections:
   • Mild/moderate: 500 mg PO 12hrly or 400 mg IV 12hrly for 7-14 days
   • Severe/complicated: 750 mg PO 12hrly or 400 mg IV 8hrly for 7-14 days
6. Skin infections
   • Mild/moderate: 500 mg PO 12hrly or 400 mg IV 12hrly for 7-14 days
   • Severe/complicated: 750 mg PO 12hrly or 400 mg IV 8hrly for 7-14 days
7. Urinary tract infections:
   • Acute uncomplicated:, 250 mg PO 12hrly for 3 days
   • Mild/moderate: 250 mg PO 12hrly or 200 mg IV 12hrly for 7-14 days
   • Severe/complicated: 500 mg PO 12hrly or 400 mg IV q12hr for 7-14 days
8. Urethral and cervical gonococcal infections:
   Uncomplicated: 250-500 mg PO once
9. Bronchiectasis

Adverse effects:

• Gastrointestinal: nausea, vomiting, abdominal pain, increased liver enzymes
• Allergic reactions
• Restlessness, insomnia, headache
• Hallucinations
• Anorexia
• Nephritis, polyuria

Use in pregnancy:

Category C: Used if benefits outweigh risks.

Warnings:

• Fluoroquinolones are associated with increased risk of tendinitis and tendon rupture; this risk is further increased in older patients (usually >60 years); in kidney, heart, and lung transplant recipients; and with use of concomitant steroid therapy
• May exacerbate muscle weakness in patients with myasthenia gravis; avoid fluoroquinolones with known history of myasthenia gravis