Enrofloxacin: veterinary dose and monograph

At a glance

Drug class

Antibiotic

Also known as

Baytril

Species with doses

Dogs, Cats, Cattle, Horses, Pigs, Birds, Rabbits, Ferrets, Guinea pigs, Reptiles, Chinchillas, Hamsters, Rats, Mice, Gerbils, Hedgehogs, Sugar gliders and Primates

General dose range

5–20 mg/kg PO q12–24h — check the species tables for the indication

Routes

PO, IV, SC, IM

Last reviewed

1 October 2026

Indications

• Susceptible Gram-negative infections
• Skin and complicated UTI infections (canine)
• Lower respiratory tract infections
• Prostatitis
• Pseudomonas soft tissue infection
• Bovine respiratory disease (Mannheimia, Pasteurella, Histophilus)
• Pasteurella URI in rabbits

Enrofloxacin dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

Dogs

• Skin / uncomplicated UTI: Plumb’s p.465 (Greene 2006): skin and urinary infections 2.5–5 mg/kg PO q12h for 7–14 days. Label/Papich 5e: 5–20 mg/kg/day; uncomplicated lower UTI 18–20 mg/kg once daily for 3 days.
• Deep pyoderma / complicated UTI / lower respiratory: Plumb’s p.465 (Greene 2006): deep pyoderma and complicated UTI 5 mg/kg PO q24h for 7–14 days (deep pyoderma may need 10–12 weeks); lower respiratory infections 5–10 mg/kg PO q24h for 7–84 days. Label maximum 30 days’ treatment.
• Pseudomonas soft tissue: Plumb’s p.465 (Greene 2006): Pseudomonas soft-tissue infections 11–20 mg/kg PO, IM or SC q12h for at least 7 days. Note this exceeds the label and Papich 5e range (5–20 mg/kg per day, higher end for intermediate-MIC organisms) — base on culture/MIC.
• Bacteraemia / sepsis: Plumb’s p.465: bacteraemia/sepsis 11 mg/kg PO, IV, IM or SC q12h (Greene); 5–20 mg/kg IV q12h (Hardie). Dilute and give IV slowly.

Cats

• Susceptible infection (MAX 5 mg/kg/day): Papich 5e and Plumb’s p.465 (label): 5 mg/kg per day PO (once daily or divided q12h), maximum 30 days; do NOT exceed 5 mg/kg/day — dose-related retinal degeneration and blindness. Avoid IV use in cats (Papich). Haemoplasmosis 5–10 mg/kg q24h for 14 days (Dowers) exceeds this ceiling.

Cattle

• Bovine respiratory disease: Papich 5e and Plumb’s p.465 (Baytril 100 label): 2.5–5 mg/kg SC once daily for 3–5 days, or 7.5–12.5 mg/kg SC once; slaughter withdrawal 28 days; not for dairy cattle or veal calves. Extra-label fluoroquinolone use in food animals is prohibited in the USA.

Horses

• Susceptible respiratory (adult, controversial): Papich 5e: 7.5 mg/kg q24h PO; 5 mg/kg q24h IV or IM. Plumb’s p.465: 5–7.5 mg/kg PO q24h (Haggett & Wilson); 7.5 mg/kg PO or IV once daily (Ainsworth). Use only in adults when other antibiotics are unsuitable; avoid in foals (arthropathy). The injectable given orally irritates the mouth — rinse afterwards.

Goats

• No reference dose for this species: The previous 2.5–5 mg/kg SC q24h row for caprine was copied from the cattle label with no species source. Neither Papich 5e nor Plumb’s gives a goat dose, and extra-label fluoroquinolone use in food animals is prohibited in several countries.

Sheep

• No reference dose for this species: The previous 2.5–5 mg/kg SC q24h row for ovine was copied from the cattle label with no species source. Neither Papich 5e nor Plumb’s gives a sheep dose, and extra-label fluoroquinolone use in food animals is prohibited in several countries.

Pigs

• Swine respiratory disease (label, single dose): Papich 5e: swine 7.5 mg/kg IM or SC behind the ear once; no more than 5 mL per injection site. Observe national restrictions on fluoroquinolones in food animals. The label withdrawal applies only to this single-dose regimen — follow the local label. Plumb’s 10e p.453 (label dosage; FDA-approved): the same 7.5 mg/kg IM or SC behind the ear once, for swine respiratory disease and for control of colibacillosis in weaned pigs. Neither reference gives a multi-day swine regimen.

Buffalo

No buffalo-specific doses are on file, so buffalo are dosed as cattle.

• Bovine respiratory disease: Papich 5e and Plumb’s p.465 (Baytril 100 label): 2.5–5 mg/kg SC once daily for 3–5 days, or 7.5–12.5 mg/kg SC once; slaughter withdrawal 28 days; not for dairy cattle or veal calves. Extra-label fluoroquinolone use in food animals is prohibited in the USA.

Birds

• Empiric Gram-negative (psittacines): Plumb’s p.465 (Flammer 2006): stable birds 20 mg/kg PO once daily with amoxicillin–clavulanate; debilitated birds 15–20 mg/kg SC in a fluid pocket once (or twice if immunocompromised) daily. IM injection causes muscle necrosis.
• Ratites: Plumb's p.466 (Jenson 1998): 1.5–2.5 mg/kg PO or SC q12h; water 10 mg/kg for 3 days. IM injection causes severe muscle necrosis — avoid IM.
• Susceptible infection (Papich): Papich 5e: birds 15 mg/kg q12h IM or PO. IM injection can cause muscle necrosis — the oral route is preferred.

Rabbits

• Pasteurella / soft tissue infection: Plumb’s p.466 (Ivey & Morrisey 2000): rabbits 5 mg/kg PO, SC, IM or IV q12h for 14 days. If giving SC, dilute (skin may slough); do not give the injectable product orally (unpalatable). Avoid in growing rabbits (cartilage effects).
• Pasteurella upper respiratory infection: Plumb’s p.466 (Antinoff 2008): 15–20 mg/kg PO twice daily for at least 14 days in mild cases and up to several months for chronic infection; the first dose may be given SC, but NOT subsequent doses (severe tissue reactions).

Ferrets

• Susceptible infection: Plumb's p.466 (Williams 2000): 10–20 mg/kg PO, IM or SC twice daily.

Guinea pigs

• Susceptible infection: Plumb's p.466: Chinchillas/Gerbils/Guinea Pigs/Hamsters/Mice/Rats 5–10 mg/kg PO or IM q12h, or 5–20 mg/kg PO/SC q24h.

Reptiles

• Susceptible bacterial infection: Papich 5e: reptiles usually 5 mg/kg/day IM or PO, given every other day or every third day. Plumb’s p.466 (Gauvin 1993): respiratory infections 5 mg/kg IM every 5 days for 25 days; chronic respiratory infection in tortoises 15 mg/kg IM every 72 h for 5–7 treatments. Dosing intervals lengthen in cooler reptiles.

Chinchillas

• Susceptible infection: Plumb's p.466 (Hayes 2000): 5–10 mg/kg PO or IM q12h; or 5–20 mg/kg PO/SC q24h; drinking water 50–200 mg/L.

Hamsters

• Susceptible infection: Plumb's p.466: 5–10 mg/kg PO or IM q12h, or 5–20 mg/kg PO/SC q24h.

Rats

• Mycoplasmal / chronic respiratory disease: Plumb's p.466: mycoplasmal pneumonia 10 mg/kg PO q12h with doxycycline 5 mg/kg PO q12h (Burke 1999); chronic respiratory disease 10–25 mg/kg PO q12h (Monks & Cowan). General: 5–10 mg/kg PO/IM q12h.

Mice

• Mycoplasmal pneumonia: Plumb's p.466: mycoplasmal pneumonia 10 mg/kg PO q12h with doxycycline 5 mg/kg PO q12h (Burke 1999); general 5–10 mg/kg PO/IM q12h.

Gerbils

• Susceptible infection: Plumb's p.466: 5–10 mg/kg PO or IM q12h, or 5–20 mg/kg PO/SC q24h.

Hedgehogs

• Susceptible infection: Carpenter Exotic Animal Formulary 6th ed, Table 8-1 (p.512): hedgehogs 2.5–10 mg/kg PO/SC/IM q12h. Avoid more than a single IM dose; dilute if given SC.

Sugar gliders

• Susceptible infection: Carpenter Exotic Animal Formulary 6th ed, Table 7-1 (p.497): sugar gliders 2.5–5 mg/kg PO/SC/IM q12–24h; 5 mg/kg PO/SC/IM q12h. Tissue necrosis can occur with parenteral use — dilute for SC injection.

Primates

• Susceptible infection (monkeys): Carpenter Exotic Animal Formulary 6th ed, Table 13-1 (p.682): 5 mg/kg PO or SC q12h ×10d in monkeys; chimpanzees 5 mg/kg PO/IM q12–24h. SC/IM may cause muscle necrosis or sterile abscesses — oral route preferred.

Contraindications

Small/medium dogs 2–8 mo of age (cartilage damage). Foals (severe arthropathy). Hypersensitivity. Caution in seizure disorders and severe renal/hepatic impairment. Extra-label use in food animals is FDA-prohibited.

Species-specific warnings

Cats: HARD CAP at 5 mg/kg/day — exceeding causes irreversible retinal degeneration and blindness. Monitor vision; discontinue at first sign of mydriasis.

Dogs: AVOID in growing dogs (2–8 mo, small/medium breeds) — arthropathy / cartilage damage. Use macrolide or beta-lactam alternative.

Horses: FATAL arthropathy in foals at therapeutic doses. Adult horses: tolerable but oral product is mouth-irritating; SC injection causes tissue necrosis.

Cattle: Extra-label use in food-producing animals is FDA-PROHIBITED. Approved cattle product: single-dose SC only, 28-day slaughter withdrawal, NOT for dairy or veal calves.

Rabbits: Useful for Pasteurella URI — well tolerated in rabbits unlike most antibiotics. Dose 5–10 mg/kg PO q12h.

Adverse effects

• Cats: ocular toxicity (mydriasis, retinal degeneration, blindness) at >5 mg/kg/day
• GI distress (vomiting, anorexia)
• Rare seizures, ataxia, depression
• Tissue damage / pain at SC injection (high pH)
• Crystalluria, hypersensitivity
• Cartilage abnormalities in young animals

Drug interactions

• Aluminium / magnesium / calcium / iron-containing antacids and sucralfate: chelate the fluoroquinolone — give 2 h apart
• Theophylline: enrofloxacin inhibits its metabolism — risk of theophylline toxicity (seizures, arrhythmias)
• NSAIDs: may increase CNS excitation / seizure risk (esp. in seizure-prone animals)
• Cyclosporine: increased nephrotoxicity risk
• Warfarin: may potentiate anticoagulant effect
• Probenecid: decreases enrofloxacin renal clearance — prolongs half-life

Pregnancy and lactation

AVOID in pregnant animals — arthropathy / cartilage damage in fetus. Excreted in milk — avoid in lactating dams or use alternatives. FDA Category C (human). Veterinary consensus: do not use during pregnancy or in animals intended for breeding unless no alternative exists.

Monitoring

• Renal and hepatic function (BUN, creatinine, ALT) — baseline and during prolonged therapy
• Ocular examination in cats — discontinue at first sign of mydriasis or vision change
• Joint examination in young growing dogs / foals — discontinue at first sign of lameness
• Neurological status — especially in seizure-prone patients or with concurrent NSAIDs
• Culture & sensitivity at therapy start — fluoroquinolone resistance is rising in vet practice

Toxicity and overdose

Cats: retinal degeneration / blindness reported at doses >5 mg/kg/day — dose-dependent and idiosyncratic. Dogs: cartilage erosion / arthropathy in 2–8 month old small/medium breeds; foals develop severe arthropathy at therapeutic doses. CNS: tremors, ataxia, seizures (especially in epileptic patients or with NSAIDs). Crystalluria at very high doses. SC injection causes tissue irritation (high pH).

Management: No specific antidote. Discontinue immediately. Cats with ocular toxicity: irreversible blindness once retinal degeneration is established. Acute overdose: IV fluid diuresis to enhance renal clearance, anti-seizure therapy (diazepam 0.5 mg/kg IV prn), supportive care. Activated charcoal if ingestion <2 h. Hemodialysis not effective.

Clinical pearls

• Cats: hard cap at 5 mg/kg/day — never exceed regardless of indication. Blindness can occur after a single high dose.
• Young dogs (2–8 mo): use a different antibiotic class to avoid cartilage damage
• Foals: do NOT use — severe arthropathy at therapeutic doses; adult horses tolerate it but oral injection product is mouth-irritating
• Pseudomonas otitis: 11–20 mg/kg PO q12h often needed — high end of dose range
• Once-daily dosing exploits concentration-dependent killing — pharmacokinetically preferred over BID in dogs
• Avoid concurrent NSAIDs in seizure-prone dogs — fluoroquinolone + NSAID = additive CNS excitation

Mechanism of action

Fluoroquinolone antibiotic. Inhibits bacterial DNA gyrase (Gram-negative) and topoisomerase IV (Gram-positive) — disrupts DNA supercoiling, replication, and repair. Bactericidal, concentration-dependent killing. In vivo, enrofloxacin is partially deethylated to ciprofloxacin (active metabolite). Excellent tissue penetration including prostate, bone, and intracellular pathogens (Mycoplasma, Brucella).

Formulations and products

• Baytril tablets 22.7 mg
• Baytril tablets 68 mg
• Baytril tablets 136 mg
• Baytril 2.27% injection
• Baytril 100 (cattle) 100 mg/mL
• Floxidin 10 % injection 100 mg/mL (MSD, 15/50/100 mL)
• Fortivir injection 100 mg/mL (Virbac)
• Cflex Power injection 100 mg/mL (Intas) — ciprofloxacin, similar use
• Floxidin VET (MSD Animal Health) — 100 mg/mL, Injection
• Fortivir (Virbac) — 100 mg/mL, Injection
• Enrostrong-10% (Mankind Veticura) — 100 mg/mL (10 %), Injection — IM or SC
• Enrostrong-20% (Mankind Veticura) — 200 mg/mL (20 %), High-concentration injection (half-volume vs 10 %)
• Enrostrong-PZ (Mankind Veticura) — Enrofloxacin 500 mg + Pefloxacin Mesilate 1500 mg + Zinc 50 mg / 5 g vial, Combination vial — reconstitute to 100 mg/mL enrofloxacin equivalent
• Enrostrong-10% Oral (Mankind Veticura) — 100 mg/mL oral solution, Oral solution
• Bayrocin Tablets (Elanco (formerly Bayer Animal Health)) — 50 mg or 150 mg tablet, Oral tablet
• Gyroflox Injection (Indian Immunologicals (IIL), Hyderabad) — 100 mg/mL (10 % w/v), Injection — IM
• Gyroflox Oral (Indian Immunologicals (IIL), Hyderabad) — 100 mg/mL (10 % oral solution), Oral solution
• Gyroflox-BH-DS Oral (Indian Immunologicals (IIL), Hyderabad) — Enrofloxacin 200 mg + Bromhexine HCl 15 mg / mL, Combination oral solution (with mucolytic) — also used in poultry drinking water

Storage

Tablets: 15–30 °C, protected from light and humidity. Injection: store ≤25 °C, do NOT refrigerate (crystals may form). Reconstituted oral suspension: refrigerate, discard after 14 days.

Before you use this dose

Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

Other antibiotics

• Cloxacillin
• Colistin (Polymyxin E)
• Danofloxacin
• Doxycycline
• Erythromycin
• Florfenicol
• Fusidic Acid
• Gamithromycin

Frequently asked questions