Ofloxacin — Veterinary Vademecum Drug Reference

Dosage & Administration Guidelines

Species	Route	Dose	Frequency	Duration & Clinical Notes
Dog	PO	5-10 mg/kg	q12h	Duration: 5-14 days depending on infection Notes: For UTIs, 5-7 days; for prostatitis, 14-28 days. Administer on an empty stomach or with food if GI upset.
Cat	PO	5-10 mg/kg	q12h	Duration: 5-14 days Notes: Use with caution in young kittens due to potential cartilage effects.
Horse	PO	5-10 mg/kg	q12h	Duration: 5-10 days Notes: Oral absorption may be variable; consider IV for severe infections.
Cattle	PO	5-10 mg/kg	q12h	Duration: 3-5 days Notes: Extra-label use; not approved for food animals in many countries. Withdrawal times must be observed.
Small Ruminants (sheep/goats)	PO	5-10 mg/kg	q12h	Duration: 3-5 days Notes: Extra-label use; caution in young animals.
Rabbit	PO	5-15 mg/kg	q12h	Duration: 7-14 days Notes: May be compounded into oral suspension.
Birds (poultry)	PO (in water)	10-20 mg/kg	q12h	Duration: 3-5 days Notes: Often administered via drinking water; ensure adequate intake.
Exotic (reptiles)	PO or IM	5-10 mg/kg	q24-48h	Duration: 7-14 days Notes: Dosing interval may be prolonged due to slower metabolism.

Clinical Indications & Species Uses

General Indications

Bacterial infections caused by susceptible organisms

Dog (Canine)

Urinary tract infections (UTIs)
Skin and soft tissue infections
Respiratory tract infections
Prostatitis
Otitis externa (topical)
Bacterial gastroenteritis

Cat (Feline)

Urinary tract infections
Skin and soft tissue infections
Respiratory tract infections
Bacterial conjunctivitis (ophthalmic)

Horse (Equine)

Respiratory tract infections
Urinary tract infections
Skin infections
Osteomyelitis (off-label)

Cattle (Bovine)

Respiratory disease (e.g., pneumonia)
Metritis
Mastitis (off-label)
Foot rot (off-label)

Small Ruminants (Sheep / Goat)

Respiratory infections
Enteritis
Mastitis (off-label)

Rabbit & Small Mammals

Respiratory infections (e.g., Pasteurella)
Urinary tract infections
Abscesses (adjunctive)

Avian & Poultry

Respiratory infections
Enteritis
Colibacillosis
Mycoplasmosis

Exotic & Other Species

Reptiles: respiratory and skin infections
Small mammals: respiratory infections

Pharmacology & Mechanism of Action

Drug Class: Fluoroquinolone antibiotic | Pharmacological Group: Antibacterial

Mechanism of Action: Ofloxacin is a 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 bactericidal and exhibits concentration-dependent killing.

Pharmacodynamics: Ofloxacin has broad-spectrum activity against Gram-negative and some Gram-positive bacteria, including Escherichia coli, Klebsiella spp., Proteus mirabilis, Pseudomonas aeruginosa, Salmonella spp., Pasteurella multocida, and Mycoplasma spp. It is less active against Streptococcus spp. and Enterococcus spp. compared to other fluoroquinolones. Its efficacy is enhanced by its ability to penetrate tissues and cells, including macrophages, making it useful against intracellular pathogens.

⚡ Pharmacokinetics Summary

Absorption: Ofloxacin is well absorbed after oral administration in most species, with bioavailability approaching 95-100% in dogs and cats. Absorption is reduced by concurrent administration of antacids containing aluminum or magnesium, and by sucralfate.

Distribution: Ofloxacin is widely distributed throughout the body, achieving high concentrations in tissues and fluids such as lung, prostate, bile, and urine. It penetrates well into cerebrospinal fluid (CSF) even without inflammation. Protein binding is low (approximately 20-25% in humans, similar in animals).

Metabolism: Ofloxacin undergoes minimal hepatic metabolism; the majority of the drug is excreted unchanged in the urine. A small fraction is metabolized to desmethyl and N-oxide metabolites.

Excretion: Ofloxacin is primarily excreted renally via glomerular filtration and tubular secretion. In dogs, approximately 70-80% of the dose is recovered in urine within 24 hours. Biliary excretion also occurs, contributing to fecal elimination.

Half-Life: Dogs: 4-6 hours; Cats: 4-6 hours; Horses: 6-8 hours; Cattle: 4-6 hours; Rabbits: 2-4 hours; Birds: 2-4 hours.

Bioavailability: Oral: ~95-100% in dogs and cats; ~80-90% in horses; ~70-80% in cattle.

Protein Binding: Approximately 20-25% in most species.

Available Formulations & Strengths

Oral Tablet 200 mg, 300 mg, 400 mg (PO)

Oral Solution 20 mg/mL (compounded) (PO)

Ophthalmic Solution 0.3% (Ophthalmic)

Otic Solution 0.3% (Otic)

Injectable Solution 20 mg/mL (for IV use, not commonly available in veterinary) (IV)

Contraindications & Clinical Warnings

Contraindications:

Hypersensitivity to fluoroquinolones
Young animals (especially puppies and kittens) due to risk of cartilage damage
Pregnant or lactating animals (unless benefit outweighs risk)
Animals with known CNS disorders (e.g., epilepsy) as it may lower seizure threshold
Concurrent use with theophylline (increased risk of toxicity)

Warnings & Clinical Precautions:

Use with caution in animals with renal or hepatic impairment; dose adjustment may be necessary.
Avoid use in growing animals (less than 8 months in medium/large breed dogs, less than 12 months in giant breeds, less than 8 months in cats) due to potential arthropathy.
May cause crystalluria; ensure adequate hydration.
Photosensitivity may occur; avoid excessive sunlight exposure.
In horses, oral administration may cause diarrhea; monitor for GI disturbances.
In food animals, observe withdrawal times; extra-label use requires veterinary oversight.
Ophthalmic solutions should not be injected.

Adverse Effects & Reactions

Common:

Gastrointestinal upset (vomiting, diarrhea, anorexia)
Nervousness or agitation
Arthralgia (especially in young animals)

Serious / Severe:

Cartilage erosion in young animals
Seizures (especially in animals with predisposing factors)
Acute renal failure (rare)
Tendon rupture (rare)
Hepatotoxicity (rare)

Rare:

Allergic reactions (urticaria, anaphylaxis)
Blood dyscrasias (leukopenia, thrombocytopenia)
Crystalluria
Ocular toxicity (with topical use)

Key Drug Interactions

Interacting Drug / Class	Clinical Effect & Mechanism	Severity
Antacids (aluminum/magnesium), sucralfate, iron, zinc	Decreased absorption of ofloxacin due to chelation; administer at least 2 hours apart.	High
Theophylline	Increased theophylline levels and risk of toxicity (seizures, arrhythmias).	High
Warfarin	Enhanced anticoagulant effect; monitor coagulation parameters.	Moderate
Corticosteroids	Increased risk of tendon rupture.	Moderate
NSAIDs	Increased risk of CNS stimulation and seizures.	Moderate
Probenecid	Decreased renal excretion of ofloxacin, increasing plasma levels.	Moderate

Overdose & Toxicity Management

Signs of Toxicity:

Vomiting
Diarrhea
CNS signs (tremors, seizures, ataxia)
Arthralgia
Renal failure (with high doses)

Emergency Treatment Protocol: Induce emesis if recent ingestion and animal is conscious. Administer activated charcoal to reduce absorption. Provide supportive care: IV fluids, anticonvulsants (e.g., diazepam) for seizures, and monitoring of renal and hepatic function. No specific antidote; treatment is symptomatic and supportive.

Food Animal Withdrawal Times

🥩 Meat: 28 days🥛 Milk: 7 days🥚 Eggs: 14 days

Withdrawal times are not established for ofloxacin in food animals in many countries; extra-label use requires extended withdrawal periods. Consult regulatory guidelines. In the US, fluoroquinolones are prohibited for extra-label use in food animals.

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).

Light Sensitivity: Light-sensitive — protect from direct exposure.

Handling & Special Conditions: Protect from light and moisture. Keep in tightly closed container. Do not freeze oral solutions.

Dispensing Status: Prescription Required (Rx Only)

Approval Status: Ofloxacin is not FDA-approved for veterinary use in the US; it is used extra-label. Human generic versions are available.

Extra-Label (Off-Label) Use: In the US, fluoroquinolones are prohibited for extra-label use in food-producing animals (AMDUCA). In companion animals, extra-label use is permitted under veterinary supervision. In the EU, similar restrictions apply.

Clinical Pearls & Practice Notes

💡 Clinical Insights: Ofloxacin is a broad-spectrum fluoroquinolone used in veterinary medicine primarily for infections caused by susceptible Gram-negative bacteria, including Pseudomonas, and some Gram-positive organisms. It is particularly useful for urinary tract infections, prostatitis, and respiratory infections. Due to its excellent tissue penetration, it is effective in deep-seated infections. However, its use in young animals is limited by the risk of cartilage damage. In food animals, its use is restricted due to public health concerns about fluoroquinolone resistance. For ophthalmic and otic infections, topical formulations are preferred. Always perform culture and sensitivity testing when possible to ensure appropriate antibiotic selection. Monitor for adverse effects, especially in animals with renal impairment. Provide supportive care and adjust dosing in hepatic or renal disease.

References & Literature

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