Ciprofloxacin — Veterinary Vademecum Drug Reference

Dosage & Administration Guidelines

Species	Route	Dose	Frequency	Duration & Clinical Notes
Dog	PO	10-20 mg/kg	q12h	Duration: 5-14 days depending on infection Notes: Use lower end for UTIs, higher for deep infections. Administer on empty stomach if possible.
Dog	IV	10-20 mg/kg	q12h	Duration: Until oral therapy possible Notes: Infuse slowly over 30 minutes to avoid adverse effects.
Cat	PO	10-20 mg/kg	q24h	Duration: 5-14 days Notes: Cats may be more sensitive to CNS effects; use caution.
Horse	PO	5-10 mg/kg	q12h	Duration: 5-10 days Notes: Oral bioavailability is low; IV may be preferred for serious infections.
Horse	IV	5-10 mg/kg	q12h	Duration: 5-10 days Notes: Administer slowly over 30 minutes.
Cattle	PO	10-15 mg/kg	q24h	Duration: 3-5 days Notes: Not approved in food animals; extra-label use requires veterinary oversight and extended withdrawal times.
Cattle	IV	5-10 mg/kg	q24h	Duration: 3-5 days Notes: Use with caution; may cause injection site reactions.
Sheep/Goat	PO	10-15 mg/kg	q24h	Duration: 3-5 days Notes: Extra-label use; observe withdrawal times.
Rabbit	PO	10-20 mg/kg	q12h	Duration: 7-14 days Notes: May be compounded into suspensions.
Bird (e.g., poultry)	PO (in water)	10-20 mg/kg	q24h	Duration: 3-5 days Notes: Ensure adequate water intake; adjust dose for flock treatment.

Clinical Indications & Species Uses

General Indications

Broad-spectrum antibacterial therapy for susceptible Gram-negative and some Gram-positive infections

Dog (Canine)

Urinary tract infections
Prostatitis
Skin and soft tissue infections
Bone and joint infections
Respiratory tract infections
Gastrointestinal infections (e.g., salmonellosis)
Otitis externa (topical or systemic)

Cat (Feline)

Urinary tract infections
Respiratory tract infections
Skin and soft tissue infections
Gastrointestinal infections
Wound infections

Horse (Equine)

Respiratory tract infections (e.g., pneumonia)
Urinary tract infections
Bone and joint infections
Septicemia (in foals)
Skin and soft tissue infections

Cattle (Bovine)

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

Small Ruminants (Sheep / Goat)

Respiratory infections
Urinary tract infections
Mastitis (off-label)
Enteritis (off-label)

Rabbit & Small Mammals

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

Avian & Poultry

Respiratory infections (e.g., Mycoplasma)
Colibacillosis
Salmonellosis
Enteritis

Exotic & Other Species

Reptiles: respiratory and skin infections
Small mammals (e.g., ferrets): respiratory and urinary infections

Pharmacology & Mechanism of Action

Drug Class: Fluoroquinolone antibiotic | Pharmacological Group: Antibacterial

Mechanism of Action: Ciprofloxacin 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 and uncoiling of bacterial DNA, leading to inhibition of DNA synthesis and ultimately bacterial cell death. It is bactericidal and exhibits concentration-dependent killing.

Pharmacodynamics: Ciprofloxacin is a broad-spectrum antibiotic with activity against many Gram-negative and some Gram-positive bacteria. It is particularly effective against Enterobacteriaceae (e.g., E. coli, Klebsiella, Salmonella), Pseudomonas aeruginosa, and some mycoplasmas. It has moderate activity against staphylococci and streptococci. Its efficacy is time-dependent on concentration, with the ratio of peak concentration (Cmax) to minimum inhibitory concentration (MIC) and area under the curve (AUC) to MIC being important predictors of clinical success. It also has a post-antibiotic effect, suppressing bacterial growth for several hours after drug levels fall below the MIC.

⚡ Pharmacokinetics Summary

Absorption: Ciprofloxacin is well absorbed after oral administration in most species, with bioavailability ranging from 50-80% in dogs and cats, but lower in horses (approximately 10-20%) and ruminants. Absorption is reduced by food, especially dairy products, due to chelation with divalent cations. In monogastric animals, peak plasma concentrations occur 1-2 hours after oral dosing.

Distribution: Ciprofloxacin is widely distributed throughout the body, achieving high concentrations in tissues and fluids such as lung, prostate, bone, and synovial fluid. It penetrates well into cells and is effective against intracellular pathogens. It crosses the blood-brain barrier to a limited extent, but concentrations in cerebrospinal fluid are lower than in plasma. Protein binding is low to moderate, ranging from 20-40% in most species.

Metabolism: Ciprofloxacin undergoes partial hepatic metabolism, primarily to desethylene-ciprofloxacin and other metabolites. The extent of metabolism varies by species; in dogs, approximately 30% is metabolized, while in cats, metabolism is less extensive. The metabolites have reduced antibacterial activity.

Excretion: Ciprofloxacin is primarily excreted by the kidneys via glomerular filtration and tubular secretion. Both the parent drug and metabolites are eliminated in urine. A small portion is excreted in feces via biliary secretion. In animals with renal impairment, dosage adjustment may be necessary.

Half-Life: Dogs: 4-6 hours; Cats: 4-6 hours; Horses: 4-9 hours; Cattle: 2-4 hours; Rabbits: 1-2 hours; Birds: 2-4 hours (varies by species).

Bioavailability: Oral: Dogs 50-80%, Cats 50-80%, Horses 10-20%, Ruminants 10-30% (poor and erratic).

Protein Binding: 20-40% depending on species.

Available Formulations & Strengths

Oral Tablet 100 mg, 250 mg, 500 mg, 750 mg (PO)

Oral Suspension (compounded) Various (e.g., 50 mg/mL) (PO)

Injectable Solution 10 mg/mL (for IV use) (IV)

Ophthalmic Solution 0.3% (Ophthalmic)

Otic Solution 0.2% (Otic)

Contraindications & Clinical Warnings

Contraindications:

Hypersensitivity to ciprofloxacin or other fluoroquinolones
Known or suspected allergy to quinolones
Young, growing animals (especially dogs and cats under 8 months of age, and large breed dogs under 18 months) due to risk of arthropathy
Pregnancy and lactation (unless benefits outweigh risks)
Animals with a history of tendon disorders
Concurrent use with tizanidine (contraindicated in humans; use caution in animals)

Warnings & Clinical Precautions:

Use with caution in animals with known or suspected CNS disorders (e.g., epilepsy) as it may lower seizure threshold.
Use with caution in animals with renal or hepatic impairment; dose adjustment may be necessary.
In young animals, avoid use unless no alternative; arthropathy (cartilage damage) has been reported.
In horses, oral administration may cause diarrhea due to alteration of gut flora; monitor closely.
In food animals, extra-label use is prohibited in the US unless under specific conditions; extended withdrawal times are required.
May cause photosensitivity; avoid excessive sunlight exposure during treatment.
Administer oral doses on an empty stomach (1 hour before or 2 hours after feeding) to maximize absorption, but if GI upset occurs, may give with food (except dairy products).
Do not administer with antacids, sucralfate, or products containing calcium, iron, zinc, or magnesium as they chelate and reduce absorption.

Adverse Effects & Reactions

Common:

Gastrointestinal disturbances (vomiting, diarrhea, anorexia)
Injection site reactions (if IV)
Restlessness or agitation

Serious / Severe:

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

Rare:

Allergic reactions (anaphylaxis)
Blood dyscrasias (leukopenia, thrombocytopenia)
Crystalluria
Photosensitivity

Key Drug Interactions

Interacting Drug / Class	Clinical Effect & Mechanism	Severity
Antacids (aluminum, magnesium, calcium)	Reduced absorption of ciprofloxacin due to chelation; separate administration by at least 2 hours.	High
Sucralfate	Reduced absorption of ciprofloxacin; separate administration by at least 2 hours.	High
Iron, zinc, calcium supplements	Reduced absorption; separate administration.	High
Theophylline	Increased theophylline levels, risk of toxicity; monitor levels and adjust dose.	High
Warfarin	Increased anticoagulant effect; monitor coagulation parameters.	Moderate
NSAIDs (e.g., flunixin, carprofen)	Increased risk of CNS stimulation and seizures.	Moderate
Corticosteroids	Increased risk of tendon rupture.	Moderate
Cyclosporine	Increased cyclosporine levels; monitor renal function.	Moderate

Overdose & Toxicity Management

Signs of Toxicity:

Vomiting
Diarrhea
Lethargy
Tremors
Seizures
Ataxia
Acute renal failure (with massive overdose)

Emergency Treatment Protocol: There is no specific antidote. Treatment is symptomatic and supportive. Induce emesis if recent ingestion and animal is conscious. Administer activated charcoal to reduce absorption. Provide intravenous fluids to maintain hydration and promote excretion. Control seizures with diazepam or barbiturates if necessary. Monitor renal and hepatic function. In severe cases, consider hemodialysis (though not commonly performed in veterinary patients).

Food Animal Withdrawal Times

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

Ciprofloxacin is not approved for use in food animals in the US. Extra-label use requires extended withdrawal times; consult FARAD (Food Animal Residue Avoidance Databank) for specific recommendations. In general, a minimum of 14 days for meat and 7 days for milk is suggested, but may be longer depending on dose and duration.

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 refrigerate oral suspension unless specified by compounding pharmacy.

Dispensing Status: Prescription Required (Rx Only)

Approval Status: Not FDA-approved for veterinary use; approved for human use. However, it is commonly used in veterinary medicine as an extra-label drug.

Extra-Label (Off-Label) Use: In the US, ciprofloxacin is not FDA-approved for veterinary species, but it is legally used in an extra-label manner under the Animal Medicinal Drug Use Clarification Act (AMDUCA) when a veterinarian establishes a valid veterinarian-client-patient relationship. Extra-label use in food animals is prohibited if an approved animal drug exists that is labeled for the condition and species, and if the drug is used in an unapproved manner. Extended withdrawal times must be observed.

Clinical Pearls & Practice Notes

💡 Clinical Insights: Ciprofloxacin is a valuable broad-spectrum antibiotic in veterinary practice, particularly for infections caused by Gram-negative organisms. However, its use should be reserved for cases where other antibiotics are ineffective or contraindicated, to minimize the development of resistance. In dogs and cats, it is often used for urinary tract infections, prostatitis, and skin infections. In horses, oral absorption is poor, so parenteral administration is preferred for systemic infections. In food animals, its use is highly restricted due to public health concerns about fluoroquinolone resistance; other fluoroquinolones like enrofloxacin are approved for some food animals, but ciprofloxacin is not. Always perform culture and sensitivity testing when possible. Monitor for adverse effects, especially in young animals and those with CNS disorders. Administer with caution in animals with renal impairment, and adjust dose accordingly. For oral administration, separate from antacids and mineral supplements. In birds, it can be administered in drinking water, but ensure adequate intake. In reptiles, dosing may vary; consult a specialist. Overall, ciprofloxacin is a potent antibiotic that should be used judiciously to preserve its efficacy.

References & Literature

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