Last reviewed 2026-04-23 · How we verify

Ciprofloxacin (BAYO9867)

Ciprofloxacin inhibits bacterial DNA gyrase and topoisomerase IV, preventing DNA replication and transcription in susceptible bacteria.

Ciprofloxacin inhibits bacterial DNA gyrase and topoisomerase IV, preventing DNA replication and transcription in susceptible bacteria. Used for Bacterial infections (respiratory tract, urinary tract, gastrointestinal, skin and soft tissue), Anthrax (inhalational exposure prophylaxis and treatment).

At a glance

Mechanism of action

As a fluoroquinolone antibiotic, ciprofloxacin binds to and inhibits DNA gyrase (in gram-negative bacteria) and topoisomerase IV (in gram-positive bacteria), enzymes essential for bacterial DNA supercoiling and separation. This dual inhibition disrupts DNA replication and transcription, leading to rapid bactericidal activity against a broad spectrum of gram-negative and gram-positive organisms.

Approved indications

• Bacterial infections (respiratory tract, urinary tract, gastrointestinal, skin and soft tissue)
• Anthrax (inhalational exposure prophylaxis and treatment)

Common side effects

• Nausea
• Diarrhea
• Vomiting
• Abdominal pain
• Headache
• Dizziness
• Tendinopathy/tendon rupture
• QT prolongation
• Photosensitivity

Key clinical trials

• Ciprofloxacin Intralesional Injection for the Treatment of Cutaneous Leishmaniasis Compared to Sodium Stibogluconate (PHASE2)
• Ciprofloxacin on Burned Patients (PHASE3)

Primary sources

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Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

• Ciprofloxacin (BAYO9867) CI brief — competitive landscape report
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• Bayer portfolio CI