Drug guide
Enrofloxacin for Dogs: Dosage, Contraindications & Safety
In dogs, enrofloxacin oral absorption and elimination are linear up to 11.5 mg/kg, twice daily, and approximately 80% of the orally administered dose enters the systemic circulation unchanged.[1][4]
Baytril Flavour Tablets in dogs are dosed at 5 mg/kg orally once daily or as a divided dose twice daily for 3 to 10 days, while Baytril® Tablets were approved at 2.5 mg/kg twice daily to a maximum of 10 days.[3][5]
Enrofloxacin is contraindicated in dogs known to be hypersensitive to quinolones and in small and medium breeds during the rapid growth phase between 2 and 8 months of age.[1][4]
Overview
Enrofloxacin oral pharmacokinetics in dogs are linear up to 11.5 mg/kg, twice daily.[1][4]
Approximately 80% of the orally administered dose enters the systemic circulation unchanged in dogs, and the primary route of excretion is via the urine.[1][4]
Dosage by species
Dog dosing for enrofloxacin differs by product and source.[2][3][5][7]
| Species | Dose | Route | Frequency / duration | Product / notes |
|---|---|---|---|---|
| Dogs | 5mg enrofloxacin per kg bodyweight per day | Oral | once daily or as a divided dose twice daily for 5 to 10 days | Enrox Flavour Tablets for Cats and Dogs; with or without food; do not exceed recommended dose.[2] |
| Dogs | 5 mg/kg | orally | once daily or as a divided dose twice daily for 3 to 10 days | Baytril Flavour Tablets; with or without food; treatment may be initiated with Baytril 5% Injection or Baytril 2.5% Injection and maintained with Baytril Flavour Tablets.[3] |
| Dogs | 2.5 mg/kg (1.13 mg/lb} of body weight | orally | twice daily (every 12 hours}; 2-3 days beyond the cessation of clinical signs to a maximum of 10 days | Baytril® Tablets; if no improvement is seen within 5 days, the diagnosis should be re-evaluated and a different course of therapy considered.[5] |
| Dogs | 5–20 mg/kg | PO, IV, or SC | q 24 h | Merck Veterinary Manual table.[7] |
Contraindications & warnings
Growth-phase use is the key dog safety limitation for enrofloxacin.[1][4]
- ❌ Contraindicated in dogs hypersensitive to quinolones — Enrofloxacin is contraindicated in dogs known to be hypersensitive to quinolones.[1][4]
- ❌ Contraindicated in small and medium breeds during rapid growth — In dogs, the use of enrofloxacin is contraindicated during the rapid growth phase between 2 and 8 months of age.[1][4]
- Large and giant breed dogs — In dogs, the safe use of enrofloxacin has not been established in large and giant breeds during the rapid growth phase.[1][4]
- Age range in larger breeds — In dogs, large breeds may be in the rapid growth phase for up to one year of age and the giant breeds for up to 18 months.[1][4]
- Dose warning — For Enrox Flavour Tablets for Cats and Dogs, do not exceed recommended dose.[2]
- Pregnancy and lactation — As enrofloxacin passes into maternal milk, use only according to the benefit/risk assessment by the responsible veterinarian.[2]
Drug interactions
Oral mineral-containing products and digoxin are the main documented interaction concerns for enrofloxacin tablets.[3]
- Calcium, aluminium or magnesium hydroxide — Concurrent oral applications of substances containing calcium, aluminium or magnesium hydroxide (e.g. antacids) can interfere with intestinal absorption of fluoroquinolones, and enrofloxacin should therefore not be used concomitantly with those products.[3]
- Iron or zinc — Concurrent oral applications of multivitamins containing iron or zinc can interfere with intestinal absorption of fluoroquinolones, and enrofloxacin should therefore not be used concomitantly with those products.[3]
- Digoxin — The combined use of fluoroquinolones with digoxin should also be avoided because of potentially increased oral bioavailability of digoxin.[3]
- Other concurrent products studied in dogs — In dogs, enrofloxacin at a daily dosage rate of 10 mg/kg was administered concurrently with praziquantel, febantel, sodium disophenol, fenthion, pyrethrins, diethylcarbamazine, ampicillin, gentamicin sulfate, penicillin, and dihydrostreptomycin, and no incompatibilities with other drugs are known at this time.[4]
Adverse effects
In adult dogs, reported adverse effects at higher oral doses included vomition and inappetence.[4]
- 52 mg/kg for 13 weeks — Adult dogs receiving enrofloxacin orally at a daily dosage rate 52 mg/kg for 13 weeks had only isolated incidences of vomition and inappetence.[4]
- 25 mg/kg for 30 consecutive days — Adult dogs receiving the tablet formulation for 30 consecutive days at a daily treatment of 25 mg/kg did not exhibit significant clinical signs nor were there effects upon the clinical chemistry, hematological or histological parameters.[4]
- 12.5 mg/kg at 12 hour intervals — Adult dogs dosed intramuscularly for three treatments at 12.5 mg/kg followed by 57 oral treatments at 12.5 mg/kg, all at 12 hour intervals, did not exhibit either significant clinical signs or effects upon the clinical chemistry, hematological or histological parameters.[4]
Overdose & toxicity
In adult dogs, daily doses of 125 mg/kg for up to 11 days induced severe toxicity including death.[4]
- 125 mg/kg for up to 11 days — Adult dogs receiving daily doses of 125 mg/kg for up to 11 days developed vomition, inappetence, depression, difficult locomotion and death.[4]
- 50 mg/kg/day for 14 days — Adult dogs receiving 50 mg/kg/day for 14 days had clinical signs of vomition and inappetence.[4]
- Beyond 11.5 mg/kg, twice daily — In dogs, the absorption and elimination characteristics beyond 11.5 mg/kg, twice daily are unknown.[1][4]
- Saturable processes at greater doses — In dogs, saturable absorption and/or elimination processes may occur at greater doses, and when saturation of the absorption process occurs, the plasma concentration of the active moiety will be less than predicted, based on the concept of dose proportionality.[1][4]
Clinical notes
Accurate body weight is needed to avoid underdosing with enrofloxacin tablets.[2]
- Weigh accurately — To ensure a correct dosage body weight should be determined as accurately as possible to avoid underdosing.[2]
- Clinical response — In dogs, the duration of treatment with Enrox Flavour Tablets may be extended depending on the clinical response and the judgement of the responsible veterinary surgeon.[2]
- Re-evaluate non-response — For Baytril® Tablets in dogs and cats, if no improvement is seen within 5 days, the diagnosis should be re-evaluated and a different course of therapy considered.[5]
- Injection-to-tablet step-down — In dogs, treatment may be initiated with Baytril 5% Injection or Baytril 2.5% Injection and maintained with Baytril Flavour Tablets.[3]
- Urinary excretion — In dogs, the primary route of excretion is via the urine.[1][4]
Frequently asked questions
What is the oral dose of enrofloxacin in dogs?
In dogs, Enrox Flavour Tablets are given at 5mg enrofloxacin per kg bodyweight per day orally once daily or as a divided dose twice daily for 5 to 10 days, and Baytril Flavour Tablets are given at 5 mg/kg orally once daily or as a divided dose twice daily for 3 to 10 days.[2][3]
Baytril® Tablets in dogs and cats were approved at 2.5 mg/kg (1.13 mg/lb} of body weight administered twice daily (every 12 hours} for 2-3 days beyond the cessation of clinical signs to a maximum of 10 days.[5]
Is enrofloxacin contraindicated in puppies?
In dogs, enrofloxacin is contraindicated in small and medium breeds during the rapid growth phase between 2 and 8 months of age.[1][4]
In large and giant breed dogs, the safe use of enrofloxacin during the rapid growth phase has not been established; large breeds may be in this phase for up to one year of age and giant breeds for up to 18 months.[1][4]
Which products interfere with oral enrofloxacin absorption in dogs?
In dogs receiving oral enrofloxacin, concurrent oral applications of substances containing calcium, aluminium or magnesium hydroxide, or multivitamins containing iron or zinc, can interfere with intestinal absorption of fluoroquinolones and enrofloxacin should therefore not be used concomitantly with those products.[3]
The combined use of fluoroquinolones with digoxin should also be avoided because of potentially increased oral bioavailability of digoxin.[3]
What adverse effects are reported in dogs at high doses of enrofloxacin?
When should the diagnosis be re-evaluated if a dog does not improve on Baytril tablets?
For Baytril® Tablets in dogs and cats, if no improvement is seen within 5 days, the diagnosis should be re-evaluated and a different course of therapy considered.[5]
Have a case in front of you?Ask WeVet — the AI assistant built for veterinarians. Differentials, treatment plans with calculated doses, drug info from trusted sources and SOAP notes.
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Dr. Ankush Mayani, M.V.Sc.
Veterinarian · Reviewed 27 Oct 2026
References
- Label: ENROSITE- enrofloxacin injection, solution - DailyMed
Passage read from this source
Pharmacokinetics: In dogs, the absorption and elimination characteristics of the oral formulation are linear (plasma concentrations increase proportionally with dose) when enrofloxacin is administered at up to 11.5 mg/kg, twice daily.2 Approximately 80% of the orally administered dose enters the systemic circulation unchanged. The eliminating organs, based on the drug's body clearance time, can readily remove the drug with no indication that the eliminating mechanisms are saturated. The primary route of excretion is via the urine. The absorption and elimination characteristics beyond this point are unknown. Saturable absorption and/or elimination processes may occur at greater doses. When saturation of the absorption process occurs, the plasma concentration of the active moiety will be less than predicted, based on the concept of…
Enrofloxacin is contraindicated in dogs known to be hypersensitive to quinolones. Based on the studies discussed under the section on Animal Safety Summary, the use of enrofloxacin is contraindicated in small and medium breeds of dogs during the rapid growth phase (between 2 and 8 months of age). The safe use of enrofloxacin has not been established in large and giant breeds during the rapid growth phase. Large breeds may be in this phase for up to one year of age and the giant breeds for up to 18 months. In clinical field trials utilizing a daily oral dose of 5.0 mg/kg, there were no reports of lameness or joint problems in any breed. However, controlled studies with histological examination…
- Dosage and administration - Enrox Flavour Tablets for Cats ...
Passage read from this source
FOR ORAL ADMINISTRATION. DO NOT EXCEED RECOMMENDED DOSE. 5mg enrofloxacin per kg bodyweight per day. Given orally once daily or as a divided dose twice daily for 5 to 10 days with or without food. Daily dose achieved as follows: | | | | --- | --- | | Cats and small dogs = | 1 Enrox Flavour Tablet 15mg per 3kg bodyweight | | Medium dogs = | 1 Enrox Flavour Tablet 50mg per 10kg bodyweight | | Large dogs = | 1 Enrox Flavour Tablet 150mg per 30kg bodyweight | The duration of treatment in dogs may be extended depending on the clinical response and the judgement of the responsible veterinary surgeon. To ensure a correct dosage body…
- Clinical particulars - Baytril Flavour Tablets
Passage read from this source
Concurrent oral applications of substances containing calcium, aluminium or magnesium hydroxide (e.g. antacids), or multivitamins containing iron or zinc can interfere with intestinal absorption of fluoroquinolones. Enrofloxacin should therefore not be used concomitantly with those products. The combined use of fluoroquinolones with digoxin should also be avoided because of potentially increased oral bioavailability of digoxin. Amount(s) to be administered and administration route The dosage rate of enrofloxacin is 5 mg/kg given orally once daily or as a divided dose twice daily for 3 to 10 days with or without food. Treatment may be initiated with Baytril 5% Injection or Baytril 2.5% Injection and maintained with Baytril Flavour Tablets. The daily dose is achieved as follows:- Cats and small dogs: 1…
- Baytril Injectable Solution for Dogs (Canada)
Passage read from this source
Pharmacokinetics: In dogs, the absorption and elimination characteristics of the oral formulation are linear (plasma concentrations increase proportionally with dose) when enrofloxacin is administered at up to 11.5 mg/kg, twice daily.4 Approximately 80% of the orally administered dose enters the systemic circulation unchanged. The eliminating organs, based on the drug’s body clearance time, can readily remove the drug with no indication that the eliminating mechanisms are saturated. The primary route of excretion is via the urine. The absorption and elimination characteristics beyond this point are unknown. Saturable absorption and/or elimination processes may occur at greater doses. When saturation of the absorption process occurs, the plasma concentration of the active moiety will be less than predicted, based on the concept of…
Enrofloxacin is contraindicated in dogs known to be hypersensitive to quinolones. Dogs: Based on the studies discussed under the section on Animal Toxicology, the use of enrofloxacin is contraindicated in small and medium breeds of dogs during the rapid growth phase (between 2 and 8 months of age). The safe use of enrofloxacin has not been established in large and giant breeds during the rapid growth phase. Large breeds may be in this phase for up to one year of age and the giant breeds for up to 18 months. In clinical field trials utilizing a daily oral dose of 5.0 mg/kg, there were no reports of lameness or joint problems in any breed. However, controlled studies with histological examination…
Adult dogs receiving enrofloxacin orally at a daily dosage rate 52 mg/kg for 13 weeks had only isolated incidences of vomition and inappetence. Adult dogs receiving the tablet formulation for 30 consecutive days at a daily treatment of 25 mg/kg did not exhibit significant clinical signs nor were there effects upon the clinical chemistry, hematological or histological parameters. Daily doses of 125 mg/kg for up to 11 days induced vomition, inappetence, depression, difficult locomotion and death while adult dogs receiving 50 mg/kg/day for 14 days had clinical signs of vomition and inappetence. Adult dogs dosed intramuscularly for three treatments at 12.5 mg/kg followed by 57 oral treatments at 12.5 mg/kg, all at 12 hour intervals, did not exhibit either significant…
Enrofloxacin has been administered to dogs at a daily dosage rate of 10 mg/kg concurrently with a wide variety of other health products including anthelmintics (praziquantel, febantel, sodium disophenol), insecticides (fenthion, pyrethrins), heartworm preventatives (diethylcarbamazine) and other antibiotics (ampicillin, gentamicin sulfate, penicillin, dihydrostreptomycin). No incompatibilities with other drugs are known at this time.
- FREEDOM OF INFORMATION SUMMARY
Passage read from this source
III. Dosage Form(s), Route(s} of Administr ation and Recommended Dosage(s) : The optimum dose of Baytril® (brand of enrofloxacin} Tablets in dogs and cats has been established at 2.5 mg/kg (1.13 mg/lb} of body weight administered twice daily (every 12 hours}. Baytril Tablets should be given twice daily for 2-3 days beyond the cessation of clinical signs to a maximum of 10 days. If no improvement is seen within 5 days, the diagnosis should be re-evaluated and a different course of therapy considered. Dosage Chart Animal Weight BAYRIL Tablets* 2.3 kg (5 lb.) 1 x 5.7 mg tablet twice daily 9.1 kg (20 lb.) 1 x 22.7 mg tablet twice daily 27.2 kg (60 lb.) 1 x 68.0 mg tablet…
Based on the bioequivalence of the C max and T max and an adequate safety margin for enrofloxacin in cats, it was determined that 2.5 mg/kg, the dose approved for dogs, is the optimal dose for cats. No adverse effects were observed. Figure 1- Enrofloxacin Bioavailabillty Study Table 1 Canine/Feline Bioequivalency Dogs Cats Animals 24 22 Peak (mcg/mL) 1.10 1.21 SEM* 0.06 0.07 Time to Peak (hrs) 1.16 1.64 SEM 0.1 0.36 AUC + 4.4 8.1 SEM 0.4 0.6 * Standard error of the mean + Area Under the Curve 3. Enrofloxacin Tablets Clinical Trial in Cats The investigators (listed below)participated in a
Statistical analyses were unnecessary to support the safety conclusions drawn. This study concludes that the oral administration of enrofloxacin tablets to 3 - 4 month old kittens is without drug related adverse effects at daily doses of 25 mg/kg (5X the labeled dosage)for up to 30 consecutive days (3X duration).
- Pharmacokinetics of enrofloxacin in clinically normal dogs ...
Passage read from this source
Pharmacodynamic variables of enrofloxacin were investigated in a neutropenic mouse Escherichia coli and staphylococcal thigh infection model. Enrofloxacin pharmacokinetics in clinically normal mice and dogs were compared to confirm that doses evaluated in the mouse model would include enrofloxacin doses appropriate for use in dogs. Mice were made neutropenic by treatment with cyclophosphamide and injected in the thigh muscle with approximately 10(6) colony-forming units of E coli (n = 2) or a staphylococcal (n = 2) clinical isolate. Enrofloxacin dosages tested ranged from 0.78 to 50 mg/kg of body weight and 6.25 to 200 mg/kg in the E coli and staphylococcal infection trials, respectively. In each 24-hour dosage trial, enrofloxacin was administered SC as a single dose or in divided…
- Table: Dosages of Quinolonesa-Merck Veterinary Manual
Passage read from this source
Dosages of Quinolones ; Difloxacin. Dogs. 5–10 mg/kg, PO, q 24 h ; Enrofloxacin. Dogs. 5–20 mg/kg, PO, IV, or SC, q 24 h.
- Table: Dosages of Quinolonesa-MSD Veterinary Manual
Passage read from this source
Dosages of Quinolones ; Difloxacin. Dogs. 5–10 mg/kg, PO, q 24 h ; Enrofloxacin. Dogs. 5–20 mg/kg, PO, IV, or SC, q 24 h.
- Pharmacokinetic evaluation of enrofloxacin administered ...
Passage read from this source
by RD Walker · 1992 · Cited by 112 — Enrofloxacin was administered orally to 6 healthy dogs at dosages of approximately 2.75, 5.5, and 11 mg/kg of body weight, every 12 hours for 4 days, ...
- Evaluation of the efficacy and safety of high dose short ...
Passage read from this source
by JL Westropp · 2012 · Cited by 136 — Enrolled dogs were randomized to group 1 (enrofloxacin 18-20 mg/kg PO q24h for 3 days) or group 2 (amoxicillin-clavulanic acid 13.75-25 mg/kg PO q12h for 14 ...
For veterinary professionals. Information supports — never replaces — clinical judgement; always check the current product label and local regulations.