Orbifloxacin

Fluoroquinolone antibiotic Antibacterial

Dosage & Administration Guidelines

Species Route Dose Frequency Duration & Clinical Notes
Dog PO 2.5-7.5 mg/kg q24h Duration: 5-14 days depending on infection severity
Notes: For skin infections, treat for at least 2-3 days beyond resolution of clinical signs. For UTI, treat for 10-14 days. Adjust dose in renal impairment.
Cat PO 2.5-7.5 mg/kg q24h Duration: 5-14 days depending on infection severity
Notes: Same as dog. Monitor for GI upset.
Horse PO Not recommended Not recommended Duration: Not recommended
Notes: Avoid in horses due to risk of arthropathy in young animals and lack of safety data.
Cattle Not applicable Not applicable Not applicable Duration: Not applicable
Notes: Not approved; extra-label use prohibited in food animals.
Small Ruminants Not applicable Not applicable Not applicable Duration: Not applicable
Notes: Not approved; extra-label use not recommended.
Rabbit PO 10-15 mg/kg q24h Duration: 5-10 days
Notes: Extrapolated from other species; use with caution due to risk of GI dysbiosis.
Bird/Poultry Not applicable Not applicable Not applicable Duration: Not applicable
Notes: Not approved; extra-label use prohibited in food-producing birds.
Exotic/Other PO Varies; often 5-10 mg/kg q24h q24h Duration: 5-14 days
Notes: Dose based on extrapolation; consult exotic animal formulary.

Clinical Indications & Species Uses

General Indications
  • Treatment of infections caused by susceptible Gram-positive and Gram-negative bacteria, including E. coli, Pasteurella, Staphylococcus, and Mycoplasma.
Dog (Canine)
  • Treatment of skin and soft tissue infections (e.g., pyoderma, wounds)
  • Urinary tract infections (UTI)
  • Respiratory tract infections (e.g., pneumonia, bronchitis)
  • Prostatitis
  • Bone and joint infections (when susceptible)
Cat (Feline)
  • Treatment of skin and soft tissue infections
  • Urinary tract infections (UTI)
  • Respiratory tract infections
  • Abscesses
Cattle (Bovine)
  • Not approved for use in cattle; extra-label use is prohibited in the US for food animals due to fluoroquinolone restrictions.
Small Ruminants (Sheep / Goat)
  • Not approved; extra-label use is limited and not recommended in food animals.
Avian & Poultry
  • Not approved for poultry; extra-label use is prohibited in the US for food-producing birds.
Exotic & Other Species
  • May be used off-label in exotic pets (e.g., reptiles, small mammals) for susceptible infections, but dosing is based on extrapolation.

Pharmacology & Mechanism of Action

Drug Class: Fluoroquinolone antibiotic | Pharmacological Group: Antibacterial

Mechanism of Action: Orbifloxacin is a bactericidal fluoroquinolone that inhibits bacterial DNA gyrase (topoisomerase II) and topoisomerase IV, enzymes essential for DNA replication, transcription, repair, and recombination. By binding to these enzymes, it prevents the supercoiling of bacterial DNA, leading to rapid bacterial cell death. It is active against both Gram-positive and Gram-negative bacteria, with enhanced activity against Gram-negative organisms.

Pharmacodynamics: Orbifloxacin exhibits concentration-dependent bactericidal activity. It has a post-antibiotic effect (PAE) against susceptible organisms, allowing for once-daily dosing. Its activity is reduced in acidic environments (e.g., urine) and in the presence of divalent cations (e.g., calcium, magnesium) which can chelate the drug. It is effective against many veterinary pathogens including E. coli, Pasteurella, Salmonella, Staphylococcus, and Mycoplasma.

⚡ Pharmacokinetics Summary

Absorption: Orbifloxacin is well absorbed after oral administration in dogs and cats, with bioavailability approaching 100%. Absorption is slightly delayed by food but not significantly reduced.
Distribution: It is widely distributed throughout the body, achieving high concentrations in tissues and body fluids, including the prostate, lung, kidney, and skin. It penetrates well into cells and reaches concentrations in tissues often exceeding plasma levels. Protein binding is low to moderate.
Metabolism: Orbifloxacin undergoes minimal hepatic metabolism; the majority of the drug is excreted unchanged in the urine. Some metabolites may be formed but are not clinically significant.
Excretion: Primarily excreted via the kidneys through glomerular filtration and tubular secretion. A small portion is eliminated in feces. In animals with renal impairment, dosage adjustment may be necessary.
Half-Life: Dogs: approximately 6-7 hours; Cats: approximately 6-8 hours; Horses: approximately 4-6 hours.
Bioavailability: Oral bioavailability is nearly 100% in dogs and cats.
Protein Binding: Approximately 20-30% in dogs and cats.

Available Formulations & Strengths

Oral Tablet 22.7 mg, 68 mg, 136 mg (PO)
Oral Suspension Not commonly available (PO)

Contraindications & Clinical Warnings

Contraindications:
  • Hypersensitivity to fluoroquinolones
  • Young, growing animals (dogs/cats under 8 months of age; large breeds under 18 months) due to risk of articular cartilage damage
  • Pregnant or lactating animals (safety not established)
  • Animals with known CNS disorders (may lower seizure threshold)
  • Use in food-producing animals (prohibited in the US)
Warnings & Clinical Precautions:
  • Use with caution in animals with renal or hepatic impairment; adjust dose if necessary.
  • May cause cartilage erosion in young animals; avoid in growing animals unless benefits outweigh risks.
  • May cause CNS stimulation; use with caution in animals with seizure disorders.
  • In cats, high doses may cause retinal toxicity; monitor for visual changes.
  • Fluoroquinolones can cause GI disturbances; administer with food if vomiting occurs.
  • Avoid concurrent administration with antacids, sucralfate, or products containing divalent cations (calcium, magnesium, aluminum, iron) as they reduce absorption.
  • Use in horses is not recommended due to potential musculoskeletal toxicity.
  • In food animals, extra-label use is prohibited; observe withdrawal times if used off-label in non-food animals.

Adverse Effects & Reactions

Common:

  • Gastrointestinal upset (vomiting, diarrhea, anorexia)
  • Increased thirst
  • Restlessness or hyperactivity

Serious / Severe:

  • Cartilage damage in young animals
  • CNS signs (seizures, ataxia, agitation)
  • Retinal degeneration in cats (especially at high doses)
  • Acute renal failure (rare)
  • Tendon rupture (rare)

Rare:

  • Allergic reactions (skin rash, anaphylaxis)
  • Hepatotoxicity
  • Blood dyscrasias
  • Photosensitivity

Key Drug Interactions

Interacting Drug / Class Clinical Effect & Mechanism Severity
Antacids (aluminum, magnesium, calcium) Reduced absorption of orbifloxacin due to chelation; administer at least 2 hours apart. High
Sucralfate Reduced absorption; separate administration by at least 2 hours. High
Iron, zinc, or calcium supplements Reduced absorption; separate administration. Moderate
Theophylline May increase theophylline levels, leading to toxicity; monitor levels. Moderate
NSAIDs (e.g., carprofen, meloxicam) Increased risk of CNS stimulation and seizures; use with caution. Moderate
Warfarin May enhance anticoagulant effect; monitor coagulation. Mild
Corticosteroids Increased risk of tendon rupture; avoid concurrent use. Moderate

Overdose & Toxicity Management

Signs of Toxicity:

  • Vomiting
  • Diarrhea
  • Anorexia
  • CNS signs (depression, seizures, tremors)
  • Articular cartilage damage in young animals
  • Acute renal failure (rare)

Emergency Treatment Protocol: Treatment is symptomatic and supportive. Induce vomiting if recent ingestion and animal is conscious. Administer activated charcoal to reduce absorption. Provide fluid therapy to maintain hydration and promote excretion. Control seizures with diazepam or barbiturates if necessary. Monitor renal function and electrolyte balance. There is no specific antidote.

Food Animal Withdrawal Times

Orbifloxacin is not approved for use in food-producing animals in the US. Extra-label use is prohibited. Therefore, no withdrawal times are established. In other countries, if used off-label, consult regulatory guidelines.

Storage, Handling & Regulatory Information

Storage Temperature: Store at controlled room temperature 20-25°C (68-77°F), with excursions permitted between 15-30°C (59-86°F).

Handling & Special Conditions: Protect from moisture. Keep container tightly closed.

Dispensing Status: Prescription Required (Rx Only)

Approval Status: Approved for use in dogs and cats in the US (e.g., Orbax tablets). Not approved for food animals.

Extra-Label (Off-Label) Use: In the US, extra-label use of fluoroquinolones in food-producing animals is prohibited by the FDA. In companion animals, extra-label use is permitted under AMDUCA with a valid veterinarian-client-patient relationship. Use in non-food animals is common but should be based on sound medical judgment.

Clinical Pearls & Practice Notes

💡 Clinical Insights: Orbifloxacin is a broad-spectrum fluoroquinolone used primarily in dogs and cats for skin, urinary, and respiratory infections. It is well-tolerated with once-daily dosing. Due to its concentration-dependent killing, it is important to achieve high peak concentrations; therefore, the full dose should be given at once rather than divided. Avoid use in young animals due to cartilage damage risk. In cats, monitor for signs of retinal toxicity, especially with prolonged use or high doses. Always culture and sensitivity when possible to ensure susceptibility. For urinary tract infections, maintain adequate hydration. Do not use in food animals due to regulatory restrictions. Store in a cool, dry place and keep out of reach of children and pets.

References & Literature

  • 📚 Plumb's Veterinary Drug Handbook
  • 📚 Papich Veterinary Pharmacology and Therapeutics
  • 📚 Compendium of Veterinary Products (CVP)