Usage
Enrofloxacin is a fluoroquinolone antibiotic indicated for the treatment of bacterial infections susceptible to it. It’s a broad-spectrum antibiotic effective against a wide range of gram-positive and gram-negative bacteria, including Pseudomonas, Staphylococcus, E. coli, and Mycoplasma. It is noteworthy that it is ineffective against anaerobes. Its pharmacological classification is antibiotic.
Enrofloxacin’s mechanism of action involves inhibiting bacterial DNA gyrase and topoisomerase IV, enzymes essential for bacterial DNA replication and repair. By blocking these enzymes, enrofloxacin prevents bacterial DNA from unwinding and duplicating, leading to bacterial cell death.
Alternate Names
Enrofloxacin is also known by its popular brand name, Baytril®. Enroxil® is another brand name available in some regions.
How It Works
Pharmacodynamics: Enrofloxacin exerts bactericidal activity by targeting bacterial DNA gyrase and topoisomerase IV. This inhibition disrupts DNA replication and repair, leading to bacterial cell death. It does not affect mammalian DNA gyrase.
Pharmacokinetics:
- Absorption: Enrofloxacin is well-absorbed orally, with approximately 80% bioavailability in dogs. Absorption is enhanced when administered on an empty stomach but can be given with food if gastrointestinal upset occurs.
- Metabolism: Enrofloxacin is partially metabolized in the liver to its active metabolite, ciprofloxacin, which also contributes to antibacterial activity.
- Elimination: Primarily eliminated through renal excretion, with both enrofloxacin and ciprofloxacin present in urine in active forms, achieving high urinary concentrations. Hepatic excretion plays a minor role. Dose adjustments are necessary in animals with renal or hepatic impairment.
Mode of Action: Enrofloxacin targets bacterial DNA gyrase and topoisomerase IV by binding to the A subunit of DNA gyrase and the ParC subunit of topoisomerase IV. This binding blocks the enzymes’ function, hindering DNA supercoiling and decatenation, preventing DNA replication and leading to bacterial death. This specific targeting of bacterial enzymes, unlike mammalian enzymes, ensures selective toxicity toward bacteria.
Dosage
Standard Dosage
Adults (Dogs): 5-20 mg/kg orally once daily or divided every 12 hours.
Adults (Cats): 5 mg/kg orally once daily or divided every 12 hours. Doses above 5 mg/kg are not recommended due to the increased risk of retinal toxicity.
Children: Not explicitly defined as “children” in veterinary medicine. Dosage is typically weight-based for immature animals. Use with caution in young, growing animals due to potential effects on cartilage development. Consult veterinary resources for species-specific pediatric dosages.
Special Cases:
- Elderly Patients: Dose adjustments based on renal and hepatic function are crucial.
- Patients with Renal Impairment: Reduce dose or extend dosing interval in dogs. In cats, avoid use or consider less retinotoxic fluoroquinolones due to heightened risk of retinal toxicity.
- Patients with Hepatic Dysfunction: Caution is advised; monitor for adverse effects.
- Patients with Comorbid Conditions: Evaluate individual cases and adjust dosage based on specific conditions, such as seizures or diabetes mellitus.
Clinical Use Cases
Dosage recommendations for specific clinical scenarios can vary based on the type and severity of the infection, the pathogen’s susceptibility, and the patient’s individual factors. Always consult relevant veterinary resources for the most accurate and up-to-date recommendations.
Dosage Adjustments
Adjustments are necessary for renal/hepatic impairment. In cats with renal impairment, enrofloxacin should be avoided or used with extreme caution.
Side Effects
Common Side Effects
Gastrointestinal effects such as vomiting, diarrhea, and decreased appetite are common.
Rare but Serious Side Effects
- Dogs: Seizures, ataxia, depression, lethargy, nervousness, elevated liver enzymes.
- Cats: Retinal damage, blindness (especially at higher doses), vocalization, aggression, articular cartilage abnormalities in young animals.
- Anaphylactic reactions (rare)
Long-Term Effects
Chronic use can lead to cartilage abnormalities in growing animals and may increase the risk of antibiotic resistance.
Adverse Drug Reactions (ADR)
Hypersensitivity reactions, including anaphylaxis, are rare but serious ADRs requiring immediate intervention. Retinal degeneration and blindness in cats, although rare, are significant ADRs.
Contraindications
- Hypersensitivity to enrofloxacin or other fluoroquinolones.
- Young, growing animals (2-8 months in small and medium-sized dogs, up to 18 months in large and giant breeds, and under 12 months in cats).
- Pregnant or lactating animals (unless benefits outweigh risks).
Drug Interactions
- Antacids, iron supplements, sucralfate, and dairy products can reduce enrofloxacin absorption.
- Concomitant use with theophylline can increase theophylline levels.
- May lower the seizure threshold; use caution with other drugs that also lower seizure thresholds.
Pregnancy and Breastfeeding
Not recommended during pregnancy and lactation due to the potential for cartilage abnormalities in growing animals. If use is essential, a benefit-risk assessment must be conducted.
Drug Profile Summary
- Mechanism of Action: Inhibits bacterial DNA gyrase and topoisomerase IV, disrupting DNA replication and repair.
- Side Effects: Vomiting, diarrhea, anorexia, seizures (rare), retinal damage and blindness in cats (rare), cartilage abnormalities in young animals.
- Contraindications: Hypersensitivity, young animals, pregnancy, lactation.
- Drug Interactions: Antacids, iron, sucralfate, dairy products, theophylline, drugs lowering seizure threshold.
- Pregnancy & Breastfeeding: Not recommended.
- Dosage: Dogs: 5-20 mg/kg/day; Cats: 5 mg/kg/day. Adjust for renal/hepatic impairment.
- Monitoring Parameters: Renal and hepatic function, observe for signs of adverse reactions, monitor affected area for infection resolution.
Popular Combinations
Combinations are not typically recommended as enrofloxacin is a broad-spectrum antibiotic. Combination therapy may be considered for severe or resistant infections in consultation with a veterinary specialist.
Precautions
- General Precautions: Pre-screening for allergies, renal/hepatic dysfunction, history of seizures.
- Specific Populations: Avoid use in young animals, pregnant/lactating animals. Use with caution in cats due to retinal toxicity risk.
- Lifestyle Considerations: No specific lifestyle considerations apart from avoiding concomitant administration with certain foods and supplements.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Enrofloxacin?
A: Dogs: 5-20 mg/kg once daily or divided every 12 hours. Cats: 5 mg/kg once daily or divided every 12 hours. Adjust dosage based on renal and hepatic function, age, and individual patient factors.
Q2: What are the common side effects of Enrofloxacin?
A: Vomiting, diarrhea, and decreased appetite are the most common side effects.
Q3: Can Enrofloxacin be used in pregnant or lactating animals?
A: Generally not recommended due to the potential for cartilage damage in developing offspring. Use only if the benefits to the mother clearly outweigh the risks to the offspring after careful assessment.
Q4: What are the contraindications for Enrofloxacin use?
A: Hypersensitivity to enrofloxacin or other fluoroquinolones, young, growing animals, pregnancy (generally), and lactation (generally).
Q5: How does Enrofloxacin work?
A: Inhibits bacterial DNA gyrase and topoisomerase IV, disrupting DNA replication and repair, resulting in bacterial cell death.
Q6: What should I do if a dose of Enrofloxacin is missed?
A: If a dose is missed, administer it as soon as you remember. However, if it’s close to the time for the next dose, skip the missed dose and resume the regular schedule. Do not double the dose.
Q7: Does Enrofloxacin interact with any other medications?
A: Yes. It can interact with antacids, iron supplements, sucralfate, dairy products, and theophylline.
Q8: Are there any specific monitoring parameters for Enrofloxacin?
A: Monitor renal and hepatic function, particularly in patients with pre-existing conditions. Observe for any signs of adverse reactions, such as vomiting, diarrhea, changes in behavior, or vision problems.
Q9: What are the signs of Enrofloxacin overdose?
A: Signs can include anorexia, vomiting, diarrhea, lethargy, and seizures. In cats, retinal damage and blindness can occur, particularly at higher doses.
Q10: Can enrofloxacin be used to treat all types of infections?
A: No. While enrofloxacin is a broad-spectrum antibiotic, it is ineffective against anaerobic infections. It should only be used for infections caused by bacteria susceptible to enrofloxacin.
