What is the proper usage and dosage of Cipro (ciprofloxacin) for treating infections?

Ciprofloxacin Dosing and Usage Guidelines

Standard Adult Dosing

For most bacterial infections in adults, ciprofloxacin is dosed at 250-750 mg orally every 12 hours, with the specific dose and duration determined by infection type and severity. 1, 2

Common Adult Dosing Regimens by Indication:

• Urinary tract infections (uncomplicated): 250 mg every 12 hours for 3 days 3
• Urinary tract infections (complicated) and pyelonephritis: 500 mg every 12 hours for 7-14 days 3
• Chronic bacterial prostatitis: 500 mg every 12 hours for 28 days 3
• Acute sinusitis: 500 mg every 12 hours for 10 days 3
• Lower respiratory tract infections: 500-750 mg every 12 hours for 7-14 days 3
• Skin and soft tissue infections: 500-750 mg every 12 hours for 7-14 days 3
• Bone and joint infections: 750 mg every 12 hours for 4-8 weeks 3
• Inhalational anthrax (post-exposure): 500 mg every 12 hours for 60 days 4, 2
• Traveler's diarrhea: 500 mg twice daily for 3-7 days 4
• Salmonella gastroenteritis (when treatment indicated): 750 mg twice daily for 14 days 4
• Infectious diarrhea: 500 mg every 12 hours for 5-7 days 3
• Typhoid fever: 500 mg every 12 hours for 10 days 3
• Uncomplicated gonorrhea: Single 250 mg dose 3
• HACEK endocarditis: 1000 mg/day PO (or 800 mg/day IV) in 2 divided doses for 4 weeks (native valve) or 6 weeks (prosthetic valve) 4

Pediatric Dosing

Ciprofloxacin should only be used in children for FDA-approved indications (complicated UTI/pyelonephritis and inhalational anthrax) or when no alternative exists, due to risk of permanent cartilage damage in weight-bearing joints. 1, 3

Pediatric Dosing by Age:

• Neonates: 15 mg/kg twice daily 1, 2
• Children (1-17 years): 10-15 mg/kg orally every 12 hours (maximum 1 g/day regardless of weight) 1, 2, 5
• Children ≥45 kg: May use adult dosing (500-750 mg every 12 hours) 2
• IV dosing (children): 10 mg/kg every 8-12 hours (maximum 400 mg/dose) 2, 5

FDA-Approved Pediatric Indications:

• Complicated UTI and pyelonephritis: 10-20 mg/kg orally every 12 hours for 10-21 days (maximum 750 mg/dose) 3
• Inhalational anthrax (post-exposure): 15 mg/kg every 12 hours for 60 days (maximum 500 mg/dose) 2

Pediatric infectious disease consultation is strongly recommended before initiating ciprofloxacin in children. 2

Renal Dose Adjustments

Dosage reduction is mandatory in renal impairment to prevent drug accumulation. 3

• CrCl 30-50 mL/min: 250-500 mg every 12 hours 2
• CrCl <30 mL/min: 250-500 mg every 18 hours 2

Special Populations

Pregnancy:

Ciprofloxacin should be avoided during pregnancy except for life-threatening infections (e.g., inhalational anthrax) where benefits outweigh risks. 1 Alternative antibiotics like ampicillin, cefotaxime, or ceftriaxone are preferred for most infections. 4, 1

Elderly (>60 years):

Elderly patients have increased risk of tendon rupture, especially if taking corticosteroids or have had kidney, heart, or lung transplants. 3 Standard adult dosing applies unless renal function is impaired. 1

Administration Guidelines

Critical Timing Considerations:

Ciprofloxacin must be administered at least 2 hours before or 6 hours after products containing divalent cations (calcium, magnesium, aluminum, iron, zinc) to avoid chelation and reduced absorption. 2, 3

• Avoid concurrent administration with antacids, sucralfate, didanosine buffered formulations, multivitamins with minerals 3
• May be taken with meals to minimize gastric distress, but not with dairy products or calcium-fortified juices alone 3
• Can be taken with a meal that contains dairy products 3

Hydration:

Patients should drink fluids liberally to prevent crystalluria, particularly if urine is alkaline. 3

Monitoring Requirements

Regular monitoring is essential during prolonged therapy: 1, 2

• ECG monitoring: At baseline, 2 weeks, and after addition of any QT-prolonging medication 1, 2
• Blood glucose: In diabetic patients due to hypoglycemia risk 1, 2
• Hepatic and renal function: Intermittently throughout treatment 1, 2
• Complete blood count: Periodically during prolonged therapy 1

Therapeutic Drug Monitoring:

For severe infections with poor clinical response, consider therapeutic drug monitoring: 1, 2

• 500 mg twice daily: Target trough 1 mg/L, peak 3 mg/L 1
• 750 mg twice daily: Target trough 1.5 mg/L, peak 4.5 mg/L 1

Critical Safety Warnings

Immediate Discontinuation Required:

Patients must discontinue ciprofloxacin immediately and contact their physician if they experience: 3

• Tendon pain, swelling, or inflammation (risk of tendon rupture, especially Achilles tendon) 3
• Peripheral neuropathy symptoms (pain, burning, tingling, numbness, weakness) 3
• Hypersensitivity reactions (skin rash, hives, difficulty breathing) 3
• Severe photosensitivity (exaggerated sunburn reaction) 3

Contraindications:

Absolute contraindications include: 4, 3

• Concurrent use with tizanidine (Zanaflex) - causes severe hypotension and sedation 3
• History of tendon disorders related to fluoroquinolone use 3

High-Risk Situations:

• CNS disorders: Use with caution in patients with seizure history or conditions predisposing to seizures 3
• Myasthenia gravis: May exacerbate muscle weakness 3
• QT prolongation: Avoid in patients with known QT prolongation or concurrent use of other QT-prolonging drugs 1

Common Adverse Effects

The most frequent adverse effects are gastrointestinal (4.9% incidence) including nausea, vomiting, diarrhea, and abdominal pain. 1, 6 Other common effects include:

• CNS effects (1.5%): Headache, dizziness, insomnia, nervousness 1, 6
• Dermatologic (1.1%): Rash, photosensitivity 1, 6
• Metabolic (4.4%): Transaminase elevations 6

Overall discontinuation rate due to adverse effects is 1.5%, with serious adverse reactions occurring in only 0.6% of patients. 6

Drug Interactions

Ciprofloxacin increases serum levels of: 3

• Theophylline: Monitor levels closely, may require dose reduction 3
• Caffeine: May cause caffeine accumulation 3
• Warfarin: Monitor INR closely 3

Resistance Considerations

Bacterial resistance to ciprofloxacin develops infrequently except in pseudomonal respiratory infections in cystic fibrosis patients. 7 Resistance occurs through chromosomal mutations affecting DNA gyrase or drug permeability, not through plasmid-mediated mechanisms. 8

Ciprofloxacin should only be used for proven or strongly suspected bacterial infections to reduce development of drug-resistant bacteria. 3