Enrofloxacin

Enrofloxacin, sold under the brand name Baytril, among others, is a fluoroquinolone antibiotic used for the treatment of animals.^[1] It is a bactericidal agent.^[1]

Enrofloxacin

Clinical data
Trade names	Baytril, others
AHFS/Drugs.com	International Drug Names
License data	US DailyMed: Enrofloxacin
Pregnancy category	AU: B3
Routes of administration	By mouth, subcutaneous, intramuscular
ATCvet code	QJ01MA90 (WHO) QD06BA51 (WHO)
Legal status
Legal status	AU: S4 (Prescription only) UK: POM (Prescription only) US: ℞-only[1][2][3]
Pharmacokinetic data
Bioavailability	80% in dogs, 65-75% in sheep [4]
Metabolism	Kidney and non-kidney[4]
Elimination half-life	4–5 hours in dogs, 6 hours in cats, 1.5 - 4.5 hours in sheep
Excretion	Bile duct (70%); kidney (30%)[5]
Identifiers
IUPAC name 1-cyclopropyl-7-(4-ethylpiperazin-1-yl)-6-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid
CAS Number	93106-60-6 Y
PubChem CID	71188
DrugBank	DB11404
ChemSpider	64326 Y
UNII	3DX3XEK1BN
KEGG	D02473 Y
ChEBI	CHEBI:35720 Y
ChEMBL	ChEMBL15511 Y
CompTox Dashboard (EPA)	DTXSID1045619
ECHA InfoCard	100.131.355
Chemical and physical data
Formula	C19H22FN3O3
Molar mass	359.401 g·mol−1
3D model (JSmol)	Interactive image
Melting point	219 to 221 °C (426 to 430 °F)
SMILES O=C(O)\C3=C\N(c2cc(N1CCN(CC)CC1)c(F)cc2C3=O)C4CC4
InChI InChI=1S/C19H22FN3O3/c1-2-21-5-7-22(8-6-21)17-10-16-13(9-15(17)20)18(24)14(19(25)26)11-23(16)12-3-4-12/h9-12H,2-8H2,1H3,(H,25,26) Y Key:SPFYMRJSYKOXGV-UHFFFAOYSA-N Y
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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 Gram-positive bacteria and is active in both stationary and growth phases of bacterial replication. Enrofloxacin is partially deethylated by CYP450 into the active metabolite ciprofloxacin, which is also a fluoroquinolone antibiotic.

In September 2005, the FDA withdrew approval of enrofloxacin for use in water to treat flocks of poultry, as the practice was noted to promote the evolution of fluoroquinolone-resistant strains of the bacterium Campylobacter, a human pathogen.^[6] Enrofloxacin is available as a fixed-dose combination medication with silver sulfadiazine for the treatment of canine otitis externa.^[7] It is available as a generic medication.

Activity and susceptibility data

Enrofloxacin is a synthetic antibacterial agent from the class of the fluoroquinolone carboxylic acid derivatives. It has antibacterial activity against a broad spectrum of Gram-negative and Gram-positive bacteria. It is effective against:

• Pseudomonas aeruginosa
• Klebsiella
• Escherichia coli
• Enterobacter
• Campylobacter
• Shigella
• Salmonella
• Aeromonas
• Haemophilus
• Proteus
• Yersinia
• Serratia
• Vibrio
• Brucella
• Chlamydia trachomatis
• Staphylococcus (including penicillinase-producing and methicillin-resistant strains)
• Mycoplasma
• Mycobacterium

Variable activity against:

• Streptococcus

Ineffective against:

• Anaerobes

The following data represent minimum inhibitory concentration ranges for a few medically significant bacterial pathogens:

• Escherichia coli - 0.022 - 0.03 μg/mL
• Staphylococcus aureus - 0.0925 - 64 μg/mL
• Pseudomonas aeruginosa - 0.05 μg/mL

Adverse effects/warnings

Enrofloxacin was banned for poultry use in the United States in 2005.^[8]

Overdosage/acute toxicity

It is unlikely that an acute overdose of either compound would result in symptoms more serious than either anorexia or vomiting, but the adverse effects noted above could occur. Dogs receiving 10 times the labeled dosage rate of enrofloxacin for at least 14 days developed only vomiting and anorexia. Death did occur in some dogs when fed 25 times the labeled rate for 11 days, however.

• Oral LD₅₀: greater than 5000 mg/kg
• Dermal LD₅₀: greater than 2000 mg/kg
• Inhalation LD₅₀: greater than 3547 mg/m3 (4-hour exposure)
• Eye effects: irritant; reversible in less than 7 days.

In cats, enrofloxacin is retinotoxic and can produce sudden-onset blindness, often irreversible.^{[9][10][11][12][13]}

Degradation

The brown rot fungus Gloeophyllum striatum can degrade the fluoroquinolone enrofloxacin using hydroxyl radicals.^[14]