Pharmacology

Ciprofloxacin is a broad-spectrum fluoroquinolone antibiotic. It inhibits bacterial DNA gyrase (topoisomerase II) and topoisomerase IV, enzymes critical for bacterial DNA replication, transcription, repair, and recombination. This action prevents cell division, ultimately leading to bacterial cell death. Ciprofloxacin exhibits bactericidal activity and is effective against a wide range of Gram-negative and some Gram-positive organisms.

Indication

Ciprofloxacin is used to treat infections caused by susceptible bacteria, including:

  • Urinary tract infections (UTIs)

  • Respiratory tract infections

  • Gastrointestinal infections (e.g., traveler’s diarrhea)

  • Bone and joint infections

  • Skin and soft tissue infections

  • Typhoid fever

  • Gonorrhea

  • Prostatitis

  • Anthrax (post-exposure prophylaxis and treatment)

Dosage & Administration

Dosage depends on the type and severity of infection, patient age, and renal function.

Adults (Oral)

  • Typical range: 250–750 mg every 12 hours

  • UTI: 250–500 mg BID for 3–14 days

  • Lower RTI: 500–750 mg BID for 7–14 days

  • Traveler’s diarrhea: 500 mg BID for 1–3 days

IV Form

  • Usually 200–400 mg every 12 hours

Children

  • Use with caution, generally for specific infections like anthrax or complicated UTIs under medical supervision.

Note: Take at least 2 hours before or 6 hours after antacids, dairy, or supplements containing calcium, iron, or magnesium to avoid absorption issues.

Drug Interactions

  • Antacids, iron, calcium, magnesium: ↓ absorption

  • Theophylline: ↑ plasma concentration and risk of toxicity

  • Warfarin: ↑ anticoagulant effect

  • NSAIDs: ↑ risk of CNS stimulation and seizures

  • Cyclosporine: ↑ serum creatinine

  • QT-prolonging drugs: Additive QT interval prolongation

Contraindications

  • Hypersensitivity to ciprofloxacin or other quinolones

  • History of tendon disorders related to fluoroquinolone use

  • Children/adolescents (except under specialist care)

  • Concurrent use with tizanidine

Side Effects

Common:

  • Nausea, diarrhea, abdominal pain

  • Dizziness, headache

  • Rash

Serious:

  • Tendinitis and tendon rupture

  • QT prolongation and arrhythmia

  • CNS effects: confusion, hallucinations, seizures

  • Peripheral neuropathy

  • Clostridium difficile-associated diarrhea

Pregnancy & Lactation

  • Pregnancy Category C (FDA): Use only if benefits outweigh risks

  • Lactation: Excreted in breast milk; avoid use or monitor closely

Precautions & Warnings

  • Avoid in children (unless necessary) due to risk of cartilage damage

  • Tendonitis and rupture risk, especially in elderly or those on corticosteroids

  • Prolonged QT interval: caution in patients with cardiac issues

  • May cause photosensitivity – avoid excessive sunlight

  • Adjust dose in renal impairment

  • Use caution in seizure disorders

Overdose Effects

  • Symptoms: Dizziness, tremors, fatigue, seizures, hallucinations

  • Treatment: Symptomatic and supportive care; consider activated charcoal if recent ingestion; hemodialysis has limited efficacy

Therapeutic Class

  • Fluoroquinolone Antibiotic

Storage Conditions

  • Store at 25°C (77°F); excursions permitted to 15–30°C (59–86°F)

  • Protect from light and moisture

  • Keep out of reach of children

Chemical Structure

  • IUPAC Name: 1-Cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(piperazin-1-yl)-quinoline-3-carboxylic acid

  • Molecular Formula: C₁₇H₁₈FN₃O₃

  • Molecular Weight: 331.35 g/mol

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