Ciprofloxacin exerts its antibacterial effect by inhibiting two critical bacterial enzymes: DNA gyrase and topoisomerase IV. According to the Lippincott Textbook of Pharmacology, these enzymes are essential for bacterial DNA replication, transcription, and repair. By binding to these enzymes, ciprofloxacin prevents the supercoiling and relaxation of DNA, leading to:

• Disruption of DNA replication.
• Formation of double-strand DNA breaks.
• Bacterial cell death.

The Lange Basic & Clinical Pharmacology further explains that ciprofloxacin's bactericidal activity is concentration-dependent, meaning higher doses result in more effective bacterial killing.

Ciprofloxacin is indicated for the treatment of a wide range of bacterial infections, including:

1. Urinary Tract Infections (UTIs): Such as cystitis and pyelonephritis.
2. Respiratory Tract Infections: Including exacerbations of chronic bronchitis and pneumonia (not first-line for community-acquired pneumonia due to resistance concerns).
3. Gastrointestinal Infections: Such as traveler's diarrhea and typhoid fever.
4. Skin and Soft Tissue Infections: Including cellulitis and wound infections.
5. Bone and Joint Infections: Such as osteomyelitis.
6. Sexually Transmitted Infections (STIs): Including gonorrhea (when resistance patterns allow).
7. Prophylaxis and Treatment of Anthrax: In cases of exposure to Bacillus anthracis.

The British National Formulary (BNF) emphasizes that ciprofloxacin should only be used for infections caused by susceptible organisms and is ineffective against viral infections.

The dosage of ciprofloxacin varies depending on the type and severity of the infection, the patient's age, weight, and renal function. The following are general guidelines:

Oral Administration

• Uncomplicated UTIs: 250-500 mg every 12 hours for 3-7 days.
• Complicated UTIs or Pyelonephritis: 500-750 mg every 12 hours for 7-14 days.
• Respiratory Tract Infections: 500-750 mg every 12 hours for 7-14 days.
• Gastrointestinal Infections: 500 mg every 12 hours for 5-7 days.
• Bone and Joint Infections: 500-750 mg every 12 hours for 4-8 weeks.

Intravenous Administration

• Severe Infections: 400 mg every 8-12 hours, adjusted based on renal function.

Renal Impairment

• Dose adjustments are necessary for patients with impaired kidney function. Consult the BNF for specific recommendations.

Ciprofloxacin should be taken with a full glass of water and can be administered with or without food. However, dairy products, antacids, or iron supplements should be avoided within 2 hours of taking ciprofloxacin, as they can reduce its absorption.

Ciprofloxacin is generally well-tolerated, but it may cause side effects. Common side effects, as listed in the Lippincott Textbook of Pharmacology, include:

• Gastrointestinal Issues: Nausea, vomiting, diarrhea, and abdominal pain.
• Central Nervous System Effects: Headache, dizziness, and insomnia.
• Skin Reactions: Rash, itching, and photosensitivity.

Less common but serious side effects may include:

• Tendonitis and Tendon Rupture: Particularly in the Achilles tendon.
• Peripheral Neuropathy: Numbness, tingling, or pain in the extremities.
• QT Prolongation: Leading to an increased risk of arrhythmias.
• Hepatotoxicity: Liver dysfunction, indicated by jaundice or elevated liver enzymes.
• Clostridioides difficile-Associated Diarrhea (CDAD): Due to disruption of normal gut flora.

Patients experiencing severe side effects should seek medical attention immediately.

Before starting ciprofloxacin, certain precautions should be taken:

1. Allergy to Fluoroquinolones: Ciprofloxacin is contraindicated in patients with a history of hypersensitivity to fluoroquinolones.
2. Tendon Disorders: Use with caution in patients with a history of tendonitis or tendon rupture, particularly in the elderly or those on corticosteroid therapy.
3. Renal or Hepatic Impairment: Dose adjustments are necessary for patients with reduced kidney or liver function.
4. Pregnancy and Breastfeeding: Ciprofloxacin should be avoided during pregnancy and breastfeeding unless the benefits outweigh the risks.
5. Pediatric Use: Fluoroquinolones are generally avoided in children due to the risk of musculoskeletal toxicity.
6. Photosensitivity: Patients should avoid excessive sunlight or UV exposure and use sunscreen while taking ciprofloxacin.

Ciprofloxacin may interact with other medications, potentially altering their effects or increasing the risk of side effects. Key interactions highlighted in the BNF and Lange Basic & Clinical Pharmacology include:

• Antacids, Sucralfate, or Iron Supplements: These can reduce the absorption of ciprofloxacin. Administer ciprofloxacin 2 hours before or 6 hours after these medications.
• Theophylline: Ciprofloxacin may increase theophylline levels, increasing the risk of toxicity.
• Warfarin: Ciprofloxacin may enhance the anticoagulant effect of warfarin, increasing the risk of bleeding.
• Corticosteroids: Concurrent use may increase the risk of tendon rupture.
• Probenecid: May increase ciprofloxacin levels by reducing its renal excretion.
• QT-Prolonging Drugs: Such as amiodarone or macrolides, which may increase the risk of arrhythmias.

Always inform your healthcare provider about all medications, supplements, and herbal products you are taking before starting ciprofloxacin.

Ciprofloxacin is the active ingredient in the brand-name medication Cipro. In pharmacies, it may also be available under various generic names, including:

• Ciprofloxacin Hydrochloride
• Ciprofloxacin Lactate (for IV use)
• Ciproxin (in some countries)