Overview
Ciprofloxacin is a broad-spectrum fluoroquinolone antibiotic used to treat various bacterial infections including urinary tract infections, respiratory infections, skin infections, and gastrointestinal infections. It works by inhibiting bacterial DNA gyrase and topoisomerase IV, preventing DNA replication. Due to serious adverse reactions, it should be reserved for infections with no alternative treatment options.
Mechanism of Action
Ciprofloxacin inhibits bacterial DNA gyrase (topoisomerase II) and topoisomerase IV, enzymes essential for DNA replication, transcription, repair, and recombination. This bactericidal action disrupts DNA synthesis and leads to bacterial cell death.
Indications
- Skin and skin structure infections
- Bone and joint infections
- Complicated intra-abdominal infections (with metronidazole)
- Infectious diarrhea
- Typhoid fever
- Uncomplicated cervical and urethral gonorrhea
- Inhalational anthrax post-exposure
- Plague treatment and prophylaxis
- Chronic bacterial prostatitis
- Lower respiratory tract infections
- Urinary tract infections (including pediatric cUTI/pyelonephritis)
- Acute sinusitis
Common Doses
- 250 mg
- 500 mg
- 750 mg
Dosage
Typical adult dosage ranges from 250-750 mg orally every 12 hours depending on infection type and severity, with durations from 3 days to 8 weeks. Pediatric dosing is weight-based (10-20 mg/kg every 12 hours, max 750 mg/dose) for specific indications. Dosage adjustments required for renal impairment.
Contraindications
- History of hypersensitivity to ciprofloxacin or other quinolones
- Concomitant administration with tizanidine
Side Effects
- Nausea, diarrhea, vomiting
- Headache, dizziness, insomnia
- Tendinitis and tendon rupture (especially Achilles)
- Peripheral neuropathy (pain, burning, tingling, weakness)
- Psychiatric reactions (anxiety, depression, hallucinations, suicidal thoughts)
- Hepatotoxicity (elevated LFTs, jaundice)
- QT prolongation and arrhythmias
- Hypersensitivity reactions (rash, anaphylaxis)
- Photosensitivity reactions
- Musculoskeletal pain and joint stiffness
- Crystalluria with alkaline urine
Interactions
- Tizanidine: contraindicated due to potentiated hypotensive/sedative effects
- Theophylline: increased theophylline levels, risk of CNS toxicity
- Oral anticoagulants (warfarin): increased anticoagulant effect
- Oral antidiabetic drugs: potentiated hypoglycemic effect
- Drugs that prolong QT interval: additive QT prolongation risk
- CYP1A2 substrates (caffeine, clozapine, ropinirole): increased plasma concentrations
- Multivalent cations (antacids, iron, calcium, dairy): decreased ciprofloxacin absorption
Counseling Points
- Take with water, at least 2 hours before or 6 hours after antacids, dairy, or mineral supplements
- Complete full course even if symptoms improve
- Discontinue and contact provider immediately for tendon pain/swelling, numbness/tingling, mood changes, or signs of hypersensitivity
- Avoid excessive sun/UV exposure; use sunscreen and protective clothing
- Stay well-hydrated to prevent crystalluria
- Monitor blood glucose closely if diabetic
- Report any muscle weakness, especially with myasthenia gravis history