Difloxacin
Difloxacin is a veterinary-labeled **fluoroquinolone antibiotic** primarily indicated for the treatment of susceptible bacterial infections in dogs. **Key Clinical Features:** * **Renal Sparing:** Unlike many other fluoroquinolones that rely heavily on renal clearance, difloxacin undergoes extensive hepatobiliary excretion (>80% eliminated in feces). This makes it uniquely advantageous for dogs with moderate to severe renal failure, as it is less likely to accumulate to toxic levels. * **Spectrum of Activity:** It exhibits good efficacy against many gram-negative and gram-positive bacilli and cocci (e.g., *Klebsiella*, *Staphylococcus*, *E. coli*, *Enterobacter*, *Campylobacter*, *Proteus*, and *Pasteurella*). * **Limitations:** It has weak activity against most anaerobes and is generally ineffective against *Enterococcus* spp. Some strains of *Pseudomonas aeruginosa* may also be resistant. > **Clinical Pearl:** Fluoroquinolones are concentration-dependent bactericidal drugs. Maximizing the peak concentration (Cmax) relative to the minimum inhibitory concentration (MIC) is crucial for clinical efficacy and preventing resistance.
Mecanismo: Difloxacin is a concentration-dependent bactericidal agent. * It actively enters the bacterial cell and targets **DNA-gyrase** (a type-II topoisomerase) and topoisomerase IV. * Inhibition of these enzymes → prevents DNA supercoiling and uncoiling → halts DNA synthesis and transcription. * The net result is rapid disruption of bacterial cell replication and subsequent cell death.
Dosificación por especie
- Susceptible infections (MIC ≤ 0.25 micrograms/mL) · 7.5 mg/kg · PO · q24h · Administer non-fasted. Appears safe and adequately absorbed, but further investigation is warranted. Unknown if it should be avoided in young, growing horses.
- Susceptible infections · 5-10 mg/kg · PO · q24h · 2-3 days beyond the cessation of clinical signs (maximum 30 days) · Administer preferably on an empty stomach, unless GI upset occurs.
Las dosis son una referencia clínica para veterinarios colegiados. Confirme siempre con la ficha técnica vigente y el paciente individual.
Vías de administración
Contraindicaciones
- Hypersensitivity to difloxacin or other quinolones
- Immature dogs during the rapid growth phase (2-8 months in small/medium breeds; up to 18 months in large/giant breeds)
- Cats (relative contraindication due to nausea/vomiting and unknown ophthalmic/retinal safety)
- Food-producing animals (extra-label use prohibited by federal law)
Efectos adversos
- Anorexia
- Vomiting
- Diarrhea
- Cartilage abnormalities (arthropathies) in growing animals
- CNS stimulation or seizures (rare)
- Facial erythema and edema (at high doses)
- Weight loss (at high doses)
Interacciones farmacológicas
- Antacids (Mg++, Al+++, Ca++) · May bind to difloxacin and prevent its absorption; separate doses by at least 2 hours.
- Dairy Products · Calcium content may decrease absorption; separate doses by at least 2 hours.
- Aminoglycosides, 3rd-gen Cephalosporins, Extended-spectrum Penicillins · Unpredictable synergism may occur against some bacteria, particularly Pseudomonas aeruginosa.
- Cyclosporine · May exacerbate nephrotoxicity and reduce the metabolism of systemic cyclosporine.
- Glyburide · Severe hypoglycemia is possible.
- Iron and Zinc supplements · Decreased difloxacin absorption; separate doses by at least 2 hours.
- Methotrexate · Increased methotrexate levels possible, resulting in toxicity.
- Nitrofurantoin · May antagonize the antimicrobial activity of fluoroquinolones; concomitant use is not recommended.
- Phenytoin · Difloxacin may alter phenytoin blood levels.
- Probenecid · May block tubular secretion and increase the blood level and half-life of difloxacin.
- Sucralfate · May inhibit absorption of difloxacin; separate doses by at least 2 hours.
- Theophylline · Difloxacin may increase theophylline blood levels, potentially leading to toxicity.
Monitorización
- Clinical efficacy (resolution of infection)
- Gastrointestinal signs (appetite, vomiting, diarrhea)
- CNS signs (especially in patients with a history of seizures)
Sobredosis
In dogs, doses up to 2.5X the maximum recommended dose (25 mg/kg) for 30 days did not cause overly significant adverse effects. Observed signs included facial erythema/edema, diarrhea, decreased appetite, and weight loss. Treatment should be supportive and symptomatic.
La referencia de fármacos de VetSheet está destinada a veterinarios colegiados como apoyo a la decisión clínica, no sustituye el juicio profesional ni la ficha técnica vigente del fabricante.