Levofloxacin

Levofloxacin is a fluoroquinolone antibacterial and the active S-enantiomer of ofloxacin. It is a human medicinal product used extra-label for selected susceptible bacterial infections in veterinary patients. Available veterinary evidence consists largely of pharmacokinetic studies and limited clinical experience, with much of its clinical use involving dogs.

Group

Fluoroquinolone antibacterial

Mechanism of Action

Levofloxacin inhibits bacterial DNA gyrase and topoisomerase IV, enzymes required for DNA replication, supercoiling and separation of replicated chromosomes. Stabilization of enzyme–DNA cleavage complexes prevents normal repair of DNA breaks and leads to bacterial death. Its antibacterial effect is concentration dependent and can persist after exposure falls below inhibitory concentrations.

Dose Rates

Dogs

Use / stage	Dose	Route	Schedule	Instructions
Susceptible bacterial infection	25 mg/kg	PO	Every 24 h
Susceptible bacterial infection	25 mg/kg	IV	Every 24 h	Slow infusion, approximately 30 minutes.

Cats

Use / stage	Dose	Route	Schedule	Instructions
Susceptible bacterial infection	20 mg/kg	PO	Every 24 h
Susceptible bacterial infection	10 mg/kg	IV	Every 24 h	Slow infusion, approximately 30 minutes.

Indications

Extra-label treatment of selected susceptible bacterial skin, wound or soft-tissue infections in companion animals.
Treatment of selected susceptible bacterial respiratory infections, including pneumonia.
Treatment of selected susceptible urinary tract infections where organism susceptibility and expected drug exposure support its use; veterinary clinical evidence is limited.

Contraindications

Growing animals with cartilage-injury risk
Use cautiously in seizure-prone animals.

Interactions

Aluminium, magnesium, calcium, iron and zinc can reduce oral absorption through chelation.

Adverse effects

Vomiting, central nervous system toxicity and juvenile arthropathy
Rapid IV delivery may cause histamine release and hypotension.

Toxicity

Stop treatment for serious neurologic or infusion reactions and provide supportive care.

Preparations

Preparation	Form	Strength	Route
Levofloxacin 250 mg tablet	Tablet	250 mg / tablet	PO
Levofloxacin 500 mg tablet	Tablet	500 mg / tablet	PO
Levofloxacin 750 mg tablet	Tablet	750 mg / tablet	PO
Levofloxacin 25 mg/mL oral solution	Oral Liquid	25 mg / mL	PO
Levofloxacin 5 mg/mL injection	Injection	5 mg / mL	IV

Monitoring and Administration

Use susceptibility results to guide treatment when possible.

Administer IV doses slowly, over approximately 30 minutes; avoid incompatible metal-ion admixtures.

Food-animal restrictions vary by jurisdiction; the reported guidance prohibits extralabel fluoroquinolone treatment of food animals in the United States.

Ophthalmic levofloxacin is listed at 0.5% and 1.5% for established susceptible corneal infection. The material does not provide a levofloxacin-specific drop frequency or an explicit salt-equivalent denominator, so no ocular systemic-dose conversion is inferred. Assess the cornea and avoid using antibiotic drops as unneeded perioperative prophylaxis.