Danofloxacin
Danofloxacin is a veterinary-specific, injectable **fluoroquinolone antibiotic** primarily used in beef cattle to treat Bovine Respiratory Disease (BRD). It exhibits concentration-dependent bactericidal activity against major respiratory pathogens like *Mannheimia haemolytica* and *Pasteurella multocida*. **Clinical Pearls:** * Like other fluoroquinolones, it has excellent tissue penetration, particularly into lung tissue, making it highly effective for respiratory infections. * It has a high volume of distribution and concentrates well in exudates and transudates. * **Regulatory Warning:** The FDA strictly prohibits the extra-label use of fluoroquinolones in food-producing animals in the USA.
Mechanism: Fluoroquinolones are bactericidal antibiotics that act by inhibiting bacterial DNA replication and transcription. * They enter the bacterium and inhibit **DNA gyrase** (topoisomerase II) and **topoisomerase IV**. * Inhibition of **DNA gyrase** → prevents DNA supercoiling → halts DNA replication. * Inhibition of **topoisomerase IV** → interferes with the separation of interlinked replicated DNA molecules. * This dual action leads to rapid bacterial cell death. The bactericidal activity is **concentration-dependent** rather than time-dependent.
Dosing by species
- Ophthalmic infections · 1 drop to affected eye · topical · q6h · As directed by veterinarian · Intensive therapy: q30-120min for short-term use (1-2 days).
- Bovine Respiratory Disease (BRD) · 6 mg/kg (1.5 mL per 100 lb body weight) SC · SC · Repeat once in approximately 48 hours · 2 doses total · Administered dosage volume should not exceed 15 mL per injection site.
- Ophthalmic infections · 1 drop to affected eye · topical · q6h · As directed by veterinarian · Intensive therapy: q30-120min for short-term use (1-2 days).
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Routes of administration
Contraindications
- Extra-label use in food-producing animals (FDA prohibited)
- Lactating dairy cattle (where milk is for human consumption)
- Veal calves
- Animals with known or suspected CNS disorders (relative contraindication)
- Known hypersensitivity to ofloxacin or other fluoroquinolones
Adverse effects
- Hypersensitivity reactions (uncommon)
- Lameness or arthropathies (especially in young animals/calves)
- Local tissue reaction at the subcutaneous injection site (may result in trim loss)
- Mild, transient ocular irritation or stinging upon application (general class effect)
- Conjunctival hyperemia (rare)
Drug interactions
- Theophylline (aminophylline) · Potential increase in serum concentrations of theophylline; increased monitoring of theophylline concentrations is recommended
Monitoring
- Clinical efficacy
- Injection site reactions
- Signs of lameness or CNS stimulation
- Clinical response to therapy (resolution of ocular discharge, inflammation, or ulceration)
- Culture and sensitivity testing prior to and during prolonged treatment if no improvement
Overdose
Limited information is available for cattle. High dosages (18-60 mg/kg for 3-6 days) in feeder calves can cause **arthropathies/lameness** (consistent with other fluoroquinolones), **CNS stimulation** (ataxia, nystagmus, tremors), inappetence, recumbency, depression, and exophthalmos. Some calves receiving 18 mg/kg twice 48 hours apart developed nasal pad erythema. In adult dogs, 2.4 mg/kg/day PO for 90 days resulted in no observable adverse effects.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.