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en-ro-FLOX-a-sin - Pronunciation guide

Brand Names

  • Baytril 100 Injectable Solution
  • Baytril Antibacterial Tablets
  • Baytril Antibacterial Taste Tabs
  • Baytril® Otic


Rx symbolEnrofloxacin is a broad spectrum bactericidal antibiotic, effective against both Gram-positive and Gram-negative bacteria.  It is not effective against anaerobic bacteria and may be variable against Streptococcus infections. Enrofloxacin is easily absorbed when given orally and can be given as a long-term antibiotic for difficult-to-treat infections.


Enrofloxacin is used to treat infections requiring long-term treatment, such as osteomyelitis, sinus infections, soft tissue infections, peritonitis, and pleuritis or pneumonia.  While enrofloxacin is well-absorbed orally and intravenously, it is usually not used intramuscularly because it is too irritating.

Dosage and Administration

Prescription medicationCyproheptadine
Method Dosage
(click row for calculator)
Concentration Period Duration
Oral 5-10 mg/kg 150 mg/tablet Daily NA
Intravenous injection1 5-10 mg/kg 100 mg/ml Daily NA


  • Federal law restricts this drug to use by or on the order of a licensed veterinarian.
  • Extra-label use of drugs in treating animals is allowable only by licensed veterinarians within the context of a valid veterinarian-client-patient relationship, and does not include drug use in treating animals by the layman (except under the supervision of a licensed veterinarian).
  • May cause developmental cartilage problems in young animals. Not recommended for use in foals.
  • 1Administer IV slowly to avoid transient neurologic signs.
  • Calculator is for educational purposes only. Follow your veterinarian's instructions regarding use of this, or any medication.

Side Effects

Some horses experience oral mucous membrane irritation, and most veterinarians recommend diluting the drug with a sweetening agent of choice that allows it to be syringed into the mouth in a diluted form, both to prevent membrane irritation and also to minimize the terrible taste.


Enrofloxacin can cause developmental cartilage abnormalities, and most veterinarians avoid use in young horses.

Animals with severe kidney or liver problems may need a reduced dose.  Hydration should be monitored and fluid therapy used in animals that tend to become dehydrated.

Enrofloxacin should be used with caution or avoided in animals at risk for seizures.

Used as an oral medication, enrofloxacin can cause mucous membrane irritation, redness, slobbering, and swelling.

Enrofloxacin is not FDA approved for use with horses.  It is commonly used and considered accepted practice.  It is a prescription drug and U.S. federal law restricts this drug to use by or on the written prescription of a licensed veterinarian.

Enrofloxacin is forbidden in drug-free competitions.  It is important to check with the proper regulatory organization.


Dosing with enrofloxacin should be separated by at least two hours from sucralfate and some antacids which may interfere with absorption.

Enrofloxacin should not be used with chloramphenicol or rifampin.

Blood levels should be monitored when bronchodilators, such as theophylline and aminophylline, are given because enrofloxacin interferes with metabolism of those drugs.


No specific information is found in literature regarding overdose in horses.


Baytril Anti-bacterial Tablet, Injection Solution Baytril Anti-bacterial Tablet, Injection Solution



About the Author

EquiMed Staff

EquiMed staff writers team up to provide articles that require periodic updates based on evolving methods of equine healthcare. Compendia articles, core healthcare topics and more are written and updated as a group effort. Our review process includes an important veterinarian review, helping to assure the content is consistent with the latest understanding from a medical professional.