Fluoroquinolone Flashcards
(6 cards)
Orbifloxacin
Effective against a variety of gram-negative pathogens and some gram-positive pathogens; ineffective for anaerobes
Orbifloxacin is a concentration-dependent bactericidal agent. It acts by inhibiting bacterial topoisomerase II (DNA-gyrase) and topoisomerase IV, thereby preventing DNA replication and transcription. The net result is disruption of bacterial cell replication. Like other fluoroquinolones, orbifloxacin has demonstrated a significant postantibiotic effect for both gram-negative and gram-positive bacteria. Clinical efficacy is associated with achieving a peak orbifloxacin concentration 10 times greater than bacterial minimum inhibitory concentration (MIC), supporting once-daily administration of high doses.
Like other fluoroquinolones, orbifloxacin has excellent activity against many gram-negative bacteria and some gram-positive bacteria. This includes most species and strains of Klebsiella spp, Staphylococcus pseudintermedius or Staphylococcus aureus, Escherichia coli, Enterobacter spp, Campylobacter spp, Bartonella spp, Shigella spp, Proteus spp, and Pasteurella spp. Some strains of Pseudomonas aeruginosa and other Pseudomonas spp are resistant to orbifloxacin, and most Enterococcus spp are resistant. Like most other fluoroquinolones, orbifloxacin has weak activity against most anaerobes and is not a good choice when treating known or suspected anaerobic infections. Acquired resistance can occur in virtually any bacterial species but is most commonly encountered in Enterobacteriaceae (E coli and related species) and staphylococci.
Contraindicated in patients with known hypersensitivity to fluoroquinolones
Fluoroquinolone use in young, growing animals may have detrimental effects on cartilage development; use fluoroquinolones in these patients only in the absence of viable treatment alternatives.
Use with caution in patients with hepatic impairment and known or suspected CNS disorders.
The most likely adverse effect is GI upset.
In cats, the oral suspension provides lower and more variable plasma concentration than tablets, and the formulations are NOT bioequivalent.
Blindness has been reported in cats receiving orbifloxacin, but it has been temporary in some cases
Many potential drug interactions
Extra-label fluoroquinolone use in food-producing animals is prohibited in the US, including backyard flocks.
Ciprofloxacin
May be used as an alternative to injectable enrofloxacin; injectable products are formulated for IV administration only
Oral bioavailability can be very low and unpredictable in dogs and cats and use by this route is no longer recommended.
believed to act by inhibiting bacterial topoisomerase II (DNA-gyrase) and topoisomerase IV, thereby preventing DNA replication and transcription. Ciprofloxacin is a bactericidal and concentration-dependent antibiotic, meaning antibacterial activity improves with peak concentrations; susceptible bacteria cell death occurs within 20 to 30 minutes of exposure. Ciprofloxacin has demonstrated a significant postantibiotic effect in both gram-negative and gram-positive bacteria and is active in both the stationary and growth phases of bacterial replication.
Ciprofloxacin has a broad spectrum of activity that is similar to enrofloxacin. Both agents have good activity against many gram-negative bacilli and cocci, including most species and strains of Pseudomonas aeruginosa, Klebsiella spp, Escherichia coli, Enterobacter spp, Campylobacter spp, Shigella spp, Salmonella spp, Aeromonas spp, Haemophilus spp, Proteus spp, Yersinia spp, Serratia spp, and Vibrio spp. Other organisms that are generally susceptible include Brucella spp, Chlamydia trachomatis, staphylococci (including penicillinase-producing and some methicillin-resistant strains), Mycoplasma spp, and Mycobacterium spp (except Mycobacterium avium subsp paratuberculosis, the etiologic agent for Johne disease). However, acquired resistance is increasingly common in some important pathogens (eg, Pseudomonas spp, Staphylococcus spp, enterobacterales [ie, E coli]). Ciprofloxacin has weak activity against streptococci and enterococci and is not recommended in the treatment of these infections; it is ineffective against anaerobes and viral, protozoal, or fungal infections.
Contraindicated in animals with a history of hypersensitivity to it or other fluoroquinolones
Fluoroquinolone use in young, growing animals may have detrimental effects on cartilage development; use fluoroquinolones in these patients only in the absence of viable treatment alternatives.
Use with caution in patients with severe renal insufficiency, seizure disorders, or dehydration.
Adverse effects include GI distress, CNS stimulation, crystalluria, and hypersensitivity. No reports of retinal toxicity secondary to ciprofloxacin in cats have been located. Articular cartilage abnormalities have been noted in young, rapidly growing animals given fluoroquinolones. Fluoroquinolones may cause photosensitization and prolonged exposure of bare skin (eg, nose) or thin hair coats to direct sunlight should be avoided.
Marbofloxacin
Effective against a variety of gram-negative pathogens and some gram-positive pathogens; ineffective for anaerobes
Marbofloxacin is believed to act by inhibiting bacterial topoisomerase II (DNA-gyrase) and topoisomerase IV, thereby preventing DNA supercoiling and DNA synthesis. Marbofloxacin is a bactericidal and concentration-dependent antibiotic, meaning antibacterial activity improves with peak concentrations; susceptible bacteria cell death occurring within 20 to 30 minutes of exposure. Clinical efficacy is associated with achieving a peak marbofloxacin concentration 10 times greater than bacterial MIC.
Marbofloxacin has a broad spectrum of activity with good activity against many gram-negative bacilli and cocci, including most species and strains of Pseudomonas aeruginosa, Klebsiella spp, Escherichia coli, Enterobacter spp, Campylobacter spp, Shigella spp, Salmonella spp, Aeromonas spp, Haemophilus spp, Pasteurella spp, Proteus spp, Yersinia spp, Serratia spp, and Vibrio spp. Marbofloxacin is considered more active against Pseudomonas aeruginosa as compared with enrofloxacin. Other organisms that are generally susceptible include Brucella spp, Chlamydia trachomatis, Staphylococcus spp (including penicillinase-producing and methicillin-resistant strains), Mycoplasma spp, and some Mycobacterium spp. Bordetella bronchiseptica was susceptible, and a significant postantibiotic effect was demonstrated ex vivo.
Fluoroquinolones have variable activity against most streptococci and enterococci, and are not usually recommended to treat these infections. Marbofloxacin is ineffective in treating anaerobic infections. Fluoroquinolones are ineffective against viral, protozoal, or fungal infections.
Resistance can occur by mutation, particularly with P aeruginosa, Klebsiella pneumoniae, Acinetobacter spp, Staphylococcus spp, and enterococci, but plasmid-mediated resistance is thought to occur only rarely.
Marbofloxacin’s leishmanicidal activity is via the TNF-alpha and nitric oxide synthase pathways
Contraindicated in animals with a history of hypersensitivity to it or other fluoroquinolones and in cats younger than 12 months of age
Fluoroquinolone use in young, growing animals may have detrimental effects on cartilage development; use fluoroquinolones in these patients only in the absence of viable treatment alternatives.
Use with caution in patients with seizure disorders.
Adverse effects most commonly include GI distress (eg, hyporexia, vomiting); neurologic signs may rarely occur.
Joint pain or neurologic signs such as behavioral changes, tremors, and ataxia may rarely occur. Hypersensitivity reactions are also possible.
Other fluoroquinolones have, in rare incidences, caused elevated hepatic enzymes, seizures, and crystalluria.
Marbofloxacin has not been shown to cause ocular toxicity in cats or predispose to Streptococcus canis necrotizing fasciitis.
Pradofloxacin
Fluoroquinolone
Pradofloxacin is a broad-spectrum third-generation bactericidal fluoroquinolone antibiotic. Its mechanism of action is inhibition of bacterial topoisomerase II (DNA gyrase) and topoisomerase IV, thereby preventing replication and transcription. The bactericidal activity of pradofloxacin is concentration dependent, meaning antibacterial activity improves with higher peak concentrations. Like other fluoroquinolones, pradofloxacin exhibits a post-antibiotic effect.
Pradofloxacin is unique among veterinary fluoroquinolones in that it has enhanced aerobic gram-positive activity and activity against anaerobes; its gram-negative activity is similar to other fluoroquinolones.
Compared with other veterinary fluoroquinolones, pradofloxacin also has enhanced activity against Mycoplasma spp. It is the only antibiotic shown to date that can eliminate M haemofelis from the blood of experimentally inoculated cats.
Pradofloxacin has weak activity against streptococci and enterococci and is not recommended in the treatment of these infections. Methicillin-resistant staphylococci (MRSP) isolates are usually resistant to all fluoroquinolones, including pradofloxacin.
Contraindications include hypersensitivity to it or other fluoroquinolones; do not administer to pregnant or lactating animals.
Fluoroquinolone use in young, growing animals may have detrimental effects on cartilage development; use fluoroquinolones in these patients only in the absence of viable treatment alternatives.
Use with caution in patients with renal insufficiency, preexisting CNS disorders (eg, epilepsy), or underlying conditions that predispose to arrhythmias (eg, electrolyte imbalances, cardiac disease).
Use with caution in immunocompromised cats, as safety has not been determined.
Adverse effects may include GI distress, photosensitivity, or myelosuppression.
Higher-than-recommended doses may result in myelosuppression (eg, thrombocytopenia, neutropenia, lymphopenia) in dogs and cats when used for longer than 7 days
In dogs, dose-dependent QT interval prolongation has been observed, and pradofloxacin could have proarrhythmic effects, especially in patients with coexisting risk factors
Enrofloxacin
Fluoroquinolone
Effective against a variety of gram-negative pathogens and some gram-positive pathogens; ineffective for anaerobes
In dogs, oral bioavailability is greater and more predictable than with ciprofloxacin.
believed to act by inhibiting bacterial topoisomerase II (DNA-gyrase) and topoisomerase IV, thereby preventing DNA supercoiling and DNA synthesis. Enrofloxacin is a bactericidal and concentration-dependent antibiotic, meaning antibacterial activity improves with peak concentrations; susceptible bacteria cell death occurring within 20 to 30 minutes of exposure. Enrofloxacin has demonstrated a significant postantibiotic effect for both gram-negative and gram-positive bacteria and is active in stationary and growth phases of bacterial replication.
Enrofloxacin has a broad spectrum of activity with good activity against many gram-negative bacilli and cocci, including most species and strains of Pseudomonas aeruginosa, Klebsiella spp, Escherichia coli, Enterobacter spp, Campylobacter spp, Shigella spp, Salmonella spp, Aeromonas spp, Haemophilus spp, Proteus spp, Yersinia spp, Serratia spp, and Vibrio spp. Other organisms that are generally susceptible include Brucella spp, Chlamydia trachomatis, staphylococci (including penicillinase-producing and methicillin-resistant strains), Mycoplasma spp, and some Mycobacterium spp (but not the etiologic agent for Johne disease).
Fluoroquinolones have variable activity against most streptococci and are not usually recommended for treatment of these infections. Enrofloxacin has weak activity against enterococci and is not recommended for the treatment of enterococcal infections. Enrofloxacin is generally ineffective in treating anaerobic infections. Although enrofloxacin and ciprofloxacin have minimal activity against anaerobes, in vitro synergy has been reported when these drugs are used with clindamycin against strains of Peptostreptococcus spp, Lactobacillus spp, and Bacteroides fragilis. Fluoroquinolones are ineffective against viral, protozoal, or fungal infections.
In vitro kill assays for enrofloxacin and its active metabolite, ciprofloxacin, have demonstrated an additive response (effect equal to the combined action of each of the drugs used separately) in dog and cat isolates of E coli, Staphylococcus pseudintermedius, and P aeruginosa. Methicillin-resistant S pseudintermedius present within biofilm have higher MICs, indicating reduced susceptibility to enrofloxacin.
Development of bacterial resistance to enrofloxacin is an ongoing concern with many different bacteria, particularly staphylococci, Enterobacterales (eg, E coli), and Pseudomonas spp. Resistance occurs by mutation, particularly with P aeruginosa, Klebsiella pneumoniae, Acinetobacter spp, and enterococci, but plasmid-mediated resistance is not thought to commonly occur. E coli resistance was demonstrated in enrofloxacin-treated weaner pigs as well as untreated pigs housed with treated animals.
Contraindicated in animals with a history of hypersensitivity to it or other fluoroquinolones
Fluoroquinolone use in young, growing animals may have detrimental effects on cartilage development; use fluoroquinolones in these patients only in the absence of viable treatment alternatives.
Use with caution in patients with severe renal insufficiency, seizure disorders, or dehydration.
Dosages greater than 5 mg/kg/day are not recommended in cats due to risk for blindness.
Adverse effects include GI distress, CNS stimulation, depression, and lethargy.
Many potential drug interactions
