Enrofloxacin
Antibiotic
View Brand Names (1)Dose and dosage
For susceptible infections:
a) 5–20 mg/kg per day PO, may be given once daily or divided and given twice daily (q12h). Treatment should continue for at least 2–3 days beyond cessation of clinical signs, to a maximum duration of therapy is 30 days. (Package insert; Baytril®—Bayer)
b) For sepsis: 5–20 mg/kg IV q12h (Hardie 2000)
c) For skin, urinary infections: 2.5–5 mg/kg PO q12h for 7–14 days;
For deep pyodermas, complicated urinary infections: 5 mg/kg PO once daily (q24h) for 7–14 days (treatment may be required for 10– 12 weeks for deep pyoderma, especially in German shepherds);
For lower respiratory tract infections: 5–10 mg/kg PO once daily (q24h) for 7–84 days;
For prostate infections: 5 mg/kg PO twice daily (q12h) for 7–14 days;
For histiocytic ulcerative colitis: 5 mg/kg PO twice daily (q12h) for 21–90 days;
For hemotropic mycoplasmosis: 5 mg/kg PO, IM q12h for 7–14 days;
For systemic orthopedic infections: 5–11 mg/kg PO, IV, IM, SC q12h for 10 days;
For Pseudomonas infections in soft tissues: 11–20 mg/kg PO, IM, SC q12h for 7 days minimum, treat as long as necessary;
For bacteremia, sepsis: 11 mg/kg PO, IV, IM, SC q12h for as long as necessary. (Greene et al. 2006)
d) For histiocytic ulcerative colitis: 5–10 mg/kg PO once daily for at least 4-6 weeks. (Burgener 2010)
For susceptible infections:
a) 5 mg/kg per day PO, may be given once daily or divided and given twice daily (q12h). Treatment should continue for at least 2–3 days beyond cessation of clinical signs, to a maximum duration of therapy is 30 days. (Package insert; Baytril®—Bayer)
b) For hemoplasmosis: 5–10 mg/kg PO q24h for 14 days. (Dowers 2009)
Note: Usage of enrofloxacin in horses remains somewhat controversial.
While there has been much discussion regarding the potential for cartilage abnormalities or other arthropathies in horses, objective data are lacking.
At present, however, enrofloxacin probably should only be used in adult horses when other antibiotics are inappropriate. If using Baytril® injection orally in horses, it can be very irritating to the mouth. This may be alleviated by coating the liquid with molasses or preparing a gel (see
Compounding Considerations below) and rinsing the horse’s mouth with water after administration.
a) 5 mg/kg IV q24h; 5–7.5 mg/kg PO q24h. (Haggett & Wilson 2008)
b) 7.5 mg/kg PO or IV once daily for susceptible respiratory infections (Ainsworth & Hackett 2004)
c) Using the compounded gel as described below (Compatibility/Compounding Considerations): 7.5 mg/kg PO once daily. Horses should be fasted for 11–14 hours prior to dosing and for 1–2 hours after dosing, but should have access to water. Rinse horse’s mouth with water after dosing to reduce risks for oral ulceration. (Epstein et al. 2004)
a) Enrofloxacin is FDA-approved for the treatment of bovine respiratory disease associated with Pasteurella haemolytica,
Pasteurella multocida, and Haemophilus sommus. It is administered by injection and is intended for the treatment of individual animals. The labeled dosage is: 2.5–5 mg/kg SC once daily for 3–5 days or 7.5–12.5 mg/kg SC once. The product is prescription only and is not for use in cattle intended for dairy production or in veal calves. Animals intended for human consumption must not be slaughtered within 28 days from the last treatment. Extralabel use of fluoroquinolones in food animals is
prohibited by the FDA.
For susceptible infections:
a) 10–20 mg/kg PO, IM, SC twice daily (Williams 2000)
a) For Pasteurella upper respiratory infections in rabbits: 15–20 mg/kg PO twice daily for a minimum of 14 days in mild cases and up to several months for chronic infections; first dose may be made by SC injection (do
NOT give subsequent doses SC or severe tissue reactions can occur). (Antinoff 2008)
b) Rabbits: 5 mg/kg PO, SC, IM or IV q12h for 14 days. Drug of choice for Pasteurella. If giving SC, dilute or skin may slough. Do not give injectable product PO because it is very unpalatable (Ivey & Morrisey 2000)
c) Hedgehogs: 5–10 mg/kg PO or SC q12h (Smith 2000)
d) Chinchillas: 5–10 mg/kg PO, IM q12h (Hayes 2000)
e) For mycoplasmal pneumonia in mice and rats: 10 mg/kg PO twice daily with doxycycline (5 mg/kg PO twice daily) (Burke 1999)
f) Chinchillas, Gerbils, Guinea Pigs, Hamsters, Mice, Rats: 5–10 mg/kg PO or IM q12h or 5–20 mg/kg PO or SC q24h. In drinking water:
50–200 mg/liter for 14 days. Do not use in young animals. (Adamcak & Otten 2000)
g) Chronic respiratory disease in rats: 10–25 mg/kg PO twice daily. If using theophylline concurrently, reduce theophylline dose by 30%. (Monks & Cowan 2009)
For susceptible infections in alpacas:
a) 5 mg/kg SC or 10 mg/kg PO once daily (Gandolf et al. 2005)
For susceptible gram-negative infections:
a) For empirical treatment in Psittacines. For stable, immunocompetent
birds: 20 mg/kg PO once daily with amoxicillin/clavulanate (125 mg/kg PO three times daily). For debilitated immunocompetent birds: 15–20 mg/kg SC in fluid pocket once daily. For debilitated, immunocompromised birds: 15–20 mg/kg SC in fluid pocket twice daily. When used orally, compounding the liver-flavored tablets grape syrup (Syrpalta®; Humco Labs) may improve acceptance. (Flammer 2006)
b) Ratites: 1.5–2.5 mg/kg PO or SC twice daily. Drinking water: 10% solution, 10 mg/kg for 3 days; 5 mg/kg IM (IM injections cause severe muscle necrosis) twice daily for 2 days (Jenson 1998)
For susceptible respiratory infections for most species:
a) 5 mg/kg IM every 5 days for 25 days; For chronic respiratory infections in tortoises: 15 mg/kg IM every 72 hours for 5–7 treatments (Gauvin 1993)
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Prevention from secondary bacterial infection.
Enrofloxacin is a bactericidal agent. The bactericidal activity of enrofloxacin is concentration dependent, with susceptible bacteria cell death occurring within 20–30 minutes of exposure. Enrofloxacin has demonstrated a significant post-antibiotic effect for both gram-negative and -positive bacteria and is active in both stationary and growth phases of bacterial replication.
Its mechanism of action is believed to act by inhibiting bacterial DNAgyrase (a type-II topoisomerase), thereby preventing DNA supercoiling and DNA synthesis.
Both enrofloxacin and ciprofloxacin have similar spectrums of activity. These agents have good activity against many gram-negative bacilli and cocci, including most species and strains of Pseudomonas aeruginosa, Klebsiella spp., E. coli, Enterobacter, Campylobacter, Shigella, Salmonella, Aeromonas,
Haemophilus, Proteus, Yersinia, Serratia, and Vibrio species. Of the currently commercially available quinolones, ciprofloxacin and enrofloxacin have the lowest MIC values for the majority of these pathogens treated. Other organisms that are generally susceptible include Brucella spp., Chlamydia trachomatis, Staphylococci (including penicillinase-producing and methicillin-resistant strains), Mycoplasma, and Mycobacterium spp. (not the etiologic agent for Johne’s Disease).
The fluoroquinolones have variable activity against most streptococci and are not usually recommended for use in these infections. These drugs have weak activity against most anaerobes and are ineffective in treating anaerobic infections.
Bacterial resistance development is an ongoing concern, as many isolates of Pseudomonas aeruginosa are now resistant to enrofloxacin. Resistance occurs by mutation, particularly with Pseudomonas aeruginosa, Klebsiella pneumonia, Acinetobacter and enterococci, but plasmid-mediated resistance is not thought to commonly occur.
The following drug interactions have either been reported or are theoretical in humans or animals receiving ciprofloxacin or enrofloxacin and may be of
significance in veterinary patients:
ANTACIDS/DAIRY PRODUCTS: Containing cations (Mg++, Al+++, Ca++) may bind to enrofloxacin and prevent its absorption; separate doses of these products by at least 2 hours
ANTIBIOTICS, OTHER (aminoglycosides, 3rd-generation cephalosporins, penicillins—extended-spectrum: Synergism may occur, but is not predictable against some bacteria (particularly Pseudomonas aeruginosa) with these compounds. Although enrofloxacin/ciprofloxacin has minimal activity against anaerobes, in vitro synergy has been reported when used with clindamycin against strains of Peptostreptococcus, Lactobacillus and Bacteroides fragilis.
CYCLOSPORINE: Fluoroquinolones may exacerbate the nephrotoxicity and reduce the metabolism of cyclosporine (used systemically)
FLUNIXIN: Has been shown in dogs to increase the AUC and elimination half-life of enrofloxacin and enrofloxacin increases the AUC and elimination half-life of flunixin; it is unknown if other NSAIDs interact with enrofloxacin in dogs
GLYBURIDE: Severe hypoglycemia possible
IRON, ZINC (oral): Decreased enrofloxacin/ciprofloxacin absorption; separate doses by at least two hours
METHOTREXATE: Increased MTX levels possible with resultant toxicity
NITROFURANTOIN: May antagonize the antimicrobial activity of the fluoroquinolones and their concomitant use is not recommended
PHENYTOIN: Enrofloxacin/ciprofloxacin may alter phenytoin levels
PROBENECID: Blocks tubular secretion of ciprofloxacin and may increase its blood level and half-life
QUINIDINE: Increased risk for cardiotoxicity
SUCRALFATE: May inhibit absorption of enrofloxacin; separate doses of these drugs by at least 2 hours
THEOPHYLLINE: Enrofloxacin/ciprofloxacin may increase theophylline blood levels; in dogs theophylline levels may be increased by about 30-50 (Trepanier 2008).
WARFARIN: Potential for increased warfarin effects
With the exception of potential cartilage abnormalities in young animals (see
Contraindications above), the adverse effect profile of enrofloxacin is usually limited to GI distress (vomiting, anorexia). In dogs, rare incidences of elevated hepatic enzymes, ataxia, seizures, depression, lethargy, and nervousness have also been reported. Hypersensitivity reactions or crystalluria could potentially
occur.
In cats, rare incidences of ocular toxicity have been reported characterized by mydriasis, retinal degeneration, and blindness. These effects were generally seen at higher dosage ranges (>15 mg/kg) and have necessitated a reduction in dosage recommendations in cats to a maximum of 5 mg/kg/day. Other rare
adverse effects seen in cats may include: vomiting, anorexia, elevated hepatic enzymes, diarrhea, ataxia, seizures, depression/lethargy, vocalization, and aggression.
While enrofloxacin has been implicated in causing antibiotic-associated diarrhea/enterocolitis in horses, due its poor activity against anaerobes, oral or parenterally administered enrofloxacin appears to carry a low risk of causing
antibiotic-associated diarrhea.
It is unlikely an acute overdose in dogs with enrofloxacin would result in clinical signs more serious than either anorexia or vomiting, but the adverse effects noted above could occur. Dogs receiving 10X the labeled dosage rate of enrofloxacin for at least 14 days developed only vomiting and anorexia.
Death occurred in some dogs when fed 25 times the labeled rate for 11 days,
however.
In cats overdoses can be serious (blindness, seizures); 20 mg/kg or more can cause retinopathy and blindness which can be irreversible.
There were 322 exposures to enrofloxacin reported to the ASPCA Animal Poison Control Center (APCC) during 2008-2009. In these cases 301 were dogs with 85 showing clinical signs and the remaining 21 cases were cats with 6 showing clinical signs. Common findings in dogs recorded in decreasing frequency included vomiting, lethargy, seizures, anorexia, depression, and diarrhea. Findings in cats recorded in decreasing frequency included seizures and recumbency.
Meat: 3 days
Egg: Should not use in bird producing eggs for human consumption.