Ciprofloxacin
Ciprofloxacin
Brand names:Cipro, Cipro XR, Ciloxan (ophthalmic)
A broad-spectrum fluoroquinolone antibiotic. Ciprofloxacin's primary tactical role is bioterrorism countermeasure for anthrax exposure (60-day post-exposure prophylaxis). It also covers complicated UTI, traveler's diarrhea, and selected gram-negative skin and soft tissue infections. FDA boxed warnings (tendinitis, peripheral neuropathy, CNS effects) and rising resistance patterns have narrowed its routine use.
Pharmacology and Actions
Ciprofloxacin is a fluoroquinolone antibiotic that inhibits bacterial DNA gyrase (topoisomerase II) and topoisomerase IV, preventing DNA replication and transcription. Bactericidal. Broad-spectrum coverage: gram-negative aerobes (E. coli, Klebsiella, Pseudomonas, Salmonella, Shigella, Campylobacter), some gram-positive coverage (less than moxifloxacin), atypicals, and Bacillus anthracis.
Indications
- Anthrax post-exposure prophylaxis and treatment (FDA bioterrorism indication)
- Complicated UTI and pyelonephritis
- Bacterial gastroenteritis (traveler's diarrhea, shigellosis)
- Skin and soft tissue infection with gram-negative coverage need
- Bone and joint infection
- Otitis externa (ophthalmic and otic preparations)
- Ophthalmic bacterial keratitis
Absolute Contraindications
- Known hypersensitivity to ciprofloxacin or other fluoroquinolones
- Concurrent use with tizanidine
Precautions and Side Effects
FDA boxed warnings: tendinitis and tendon rupture (especially Achilles, age over 60, corticosteroid use); peripheral neuropathy (may be permanent); CNS effects (anxiety, hallucinations, seizures); exacerbation of myasthenia gravis. Aortic dissection risk in older adults. Common GI: nausea, diarrhea, C. difficile. Dysglycemia (especially hypoglycemia in elderly diabetics). Photosensitivity. QT prolongation. Drug interactions: cation-containing antacids and supplements (calcium, magnesium, aluminum, iron, zinc) reduce absorption dramatically - separate by at least 2 hours before or 6 hours after; increases warfarin effect (INR monitoring needed); increases theophylline levels (toxicity risk); concurrent tizanidine contraindicated due to severe hypotension and sedation; NSAIDs may increase seizure risk; QT-prolonging agents (amiodarone, sotalol, methadone) increase arrhythmia risk. Half-life 3 to 5 hours, extended in renal impairment - dose adjust if CrCl under 50. Pregnancy Category C (avoid unless anthrax or other life-threatening infection). Present in breast milk; avoid if possible. Cartilage toxicity concern in pediatrics but used for anthrax exposure (15 mg/kg PO every 12 hours; max 500 mg). Counsel patients to avoid strenuous lower-extremity activity during therapy and 2 weeks after, and to stop the drug immediately at the first sign of tendon pain.
Adult Dosing
Pediatric Dosing
Generally avoided in pediatrics except for serious infection or anthrax exposure. Anthrax: 15 mg/kg PO every 12 hours (max 500 mg per dose), or 10 mg/kg IV every 12 hours.
Pharmacokinetics
Peak Effect: 1 to 2 hours.
Duration: 8 to 12 hours.
Storage and Handling
Tablets: room temperature, protect from light and moisture. IV solution: room temperature; protect from light; do not refrigerate (precipitates). Ophthalmic: refrigerated or room temperature per labeling.
Reconstitution:
IV solution comes premixed or as concentrate requiring dilution to 1 to 2 mg/mL in compatible IV fluid. Infuse over at least 60 minutes (rapid infusion increases hypotension and CNS adverse effects).
TCCC and TECC Role
Ciprofloxacin is not in the TCCC core wound prophylaxis formulary (moxifloxacin is the historical TCCC oral choice and now cefadroxil per TCCC 2026). Ciprofloxacin's tactical role is bioterrorism countermeasure (anthrax exposure) and operational antibiotic for traveler's diarrhea, complicated UTI, or skin and soft tissue infection in deployment medicine. Mission impact is minor at standard doses, though the boxed warnings make this a deliberately chosen antibiotic, not a default.
Ciprofloxacin's tactical niche has narrowed substantially. For wound prophylaxis, cefadroxil has replaced fluoroquinolones in TCCC 2026 doctrine. For traveler's diarrhea, azithromycin has displaced ciprofloxacin in most regions due to fluoroquinolone resistance in Campylobacter, and the boxed warnings have soured many providers on routine fluoroquinolone use. The clear remaining indications are anthrax exposure (where ciprofloxacin is doctrine and a 60-day course is required), complicated UTI with known sensitivity, and selected gram-negative bone or joint infection. For most other situations, alternatives exist with cleaner risk profiles.
Using ciprofloxacin as a general-purpose first-line antibiotic. The boxed warnings and rising resistance patterns make fluoroquinolones a second-line or specific-indication choice in most modern protocols. The other mistake is failing to counsel patients on tendon precautions during therapy. Cation interactions are real and dramatic - antacids, calcium tablets, iron, magnesium, and even dairy products can wipe out oral absorption.
This drug profile is provided as educational reference material for trained medical providers. It is not medical advice, not a substitute for formal training, and not a substitute for current published guidelines or medical direction.
Drug administration is governed by your scope of practice, agency standing orders, medical director protocols, and applicable state and federal regulations. Controlled substances are subject to additional handling, accountability, and documentation requirements per DEA and state law. Always verify dosing, indications, contraindications, and route of administration against current published guidelines and your local protocols before administration.
If this content is being viewed during a medical emergency, call 911 immediately and follow the direction of your local emergency dispatch and medical control. Do not use this reference as a substitute for emergency medical services.
Drug information evolves. Last reviewed dates and source citations are provided for each entry. Confirm currency against the cited source before clinical use.
Penn Tactical Solutions publishes this reference for educational purposes. PTS does not provide medical direction and does not assume responsibility for clinical decisions made in the field. Clinical responsibility rests with the administering provider, their medical director, and their agency.
Educational reference for trained medical providers. Not medical advice. Not a substitute for formal training, current published guidelines, or medical direction. Drug administration is governed by your scope of practice, agency standing orders, medical director protocols, and applicable state and federal regulations. Controlled substances require additional storage, accountability, and documentation per DEA and state law.
In a medical emergency, call 911. This reference is not a substitute for emergency medical services.
Verify dosing, indications, and contraindications against current published guidelines and your local protocols before administration. Confirm content currency against the source citation. Penn Tactical Solutions does not provide medical direction. Clinical responsibility rests with the administering provider, their medical director, and their agency.
Ciprofloxacin
| IV/IO | 400 mg IV every 8 to 12 hours infused over 60 minutes. For severe infection: 400 mg IV every 8 hours. (Within 15 minutes) |
| IM | None (not approved for IM use). (None) |
| IN | None (None) |
| PO | 500 mg PO every 12 hours for most indications. Severe or complicated infection: 750 mg PO every 12 hours. Anthrax post-exposure prophylaxis: 500 mg PO every 12 hours for 60 days. Take with full glass of water; separate from cation-containing antacids and supplements by at least 2 hours before or 6 hours after. (Plasma levels within 1 to 2 hours) |