Brand Name: Zeniquin

Available Sizes: 25 mg, 50 mg, 100 mg, 200 mg

Background

Human beings have been at odds with microbes since the beginning of time and the quest for new medications continues even today. When sulfa drugs came on the scene in the 1940s, an age of antibiotics was born and a new dimension opened in the combat against microbes. From there, a proliferation of antibiotics have developed with each new medication exploiting a different aspect of bacterial metabolism until it seemed that the war on microbes would soon be won.

Despite this progress, one particular bacterial species remained seemingly invincible: Pseudomonas aeruginosa. This species was able to change its antibiotic susceptibility with each antibiotic exposure and become resistant to multiple drugs in response to every medication used against it. Eventually, the aminoglycoside class of antibiotics was developed and there was finally a way to kill Pseudomonas fairly reliably but the price was that medication was injectable only, necessitating hospitalization for the patient, and potential kidney damage could result with prolonged use.

A major breakthrough against Pseudomonas came with the development of the fluoroquinolone class of antibiotics (beginning with enrofloxacin, its counterpart for human use ciprofloxacin, and eventually marbofloxacin and others). These medications are active against many bacterial types including Pseudomonas. They are available as tablets and are not associated with the serious side effects that plagued the aminoglycoside group. Marbofloxacin is a veterinary fluoroquinolone designed to provide a safe and more convenient means of treating infections where aminoglycoside antibiotics might have been selected in the past.

How this Medication Works 

Fluoroquinolones work by deactivating bacterial enzymes necessary for the transcription of DNA. DNA is tightly coiled in order to fit inside a cell. Segments to be used must be uncoiled by an enzyme called DNA gyrase. The fluoroquinolone antibiotic deactivates DNA gyrase, making the reading of DNA impossible. The bacterial cell dies. Mammalian DNA gyrase is of a completely different shape and remains unharmed. 

How this Medication is Used

This medication may be used in either dogs or cats to combat different types of infections, especially those involving Pseudomonas. Marbofloxacin is also active against Staphylococci and might be used for skin infections, but it is not felt to be a first line drug and is generally reserved for resistant infections.

Marbofloxacin is not helpful against anaerobic infections (such as are typical in the mouth or in bite wound abscesses), however, but it is commonly combined with other antibiotics for a boost in function.

• Marbofloxacin is best given on an empty stomach but if nausea becomes an issue, it can be given with food.
• It is usually given either once or twice daily as a tablet. If a dose is accidentally skipped, do not double up on the next dose.
• Do not use cheese (or other dairy products) as a treat to hide the pill as calcium will interfere with its absorption.
• Tablets should be stored at room temperature, protected from light.
• Dose adjustments may be needed for patients with liver or kidney disease.

Side Effects

As with most oral medications, the most common side effects of marbofloxacin are related to the GI tract: vomiting, diarrhea, and reduced appetite. Giving a small amount of food can help with this problem should it arise.

In immature dogs (less than 8 months of age for medium dogs, less than 12 months of age for large breeds, and less than 18 months for giant breeds) damage to developing joint cartilage can occur. This phenomenon is only seen in growing dogs and does not seem to be a problem in cats, though the manufacturer recommends against using marbofloxacin in cats under 1 year of age. It is preferable not to use this medication in puppies unless the severity of the infection warrants it.

Enrofloxacin, the first veterinary fluoroquinolone, was found to lead to retinal damage and blindness when used in higher doses in cats. This is because the feline retina tends to accumulate enrofloxacin. Marbofloxacin was developed to have less affinity for the feline retina but it is unknown if this problem still occurs in higher doses.

Fluoroquinolone antibiotics may lower the seizure threshold and increase a patient's tendency to have seizures. This is of no concern in a normal animal but is worth a cautionary statement for patients with a pre-existing seizure disorder or with liver or kidney disease.

Marbofloxacin can increase skin sensitivity to the sun.

Interactions with Other Drugs

Sucralfate (a medication used to treat stomach ulcers) may bind marbofloxacin and prevent it from entering the body. These medications should be given at least 2 hours apart if they are used together. A similar phenomenon occurs with magnesium and calcium-containing antacids.

Theophylline (an airway dilator) blood levels may be higher than usual if this medication is used concurrently with marbofloxacin. The dose of theophylline may need to be reduced.

If marbofloxacin is used with oral cyclosporine (an immunosuppressive medication used for inflammatory bowel disease), the kidney-damaging properties of cyclosporine may become worse.

Medications or supplements containing iron, zinc, magnesium, or aluminum will bind marbofloxacin and prevent absorption into the body. The timing of giving those medications should be separated from marbofloxacin by at least 2 hours. Similarly, do not use cheese (or any dairy product) as a treat to give with marbofloxacin tablets as the calcium can bind the drug and prevent absorption.

Concerns and Cautions

Pseudomonas infections are especially common in canine ears. In this location, higher doses of marbofloxacin are needed to clear this infection. Expect expense as marbofloxacin is a unique antibiotic and at this time there is no comparable generic.

Marbofloxacin should not be used in pregnant, nursing pets, kittens under age one year, nor in puppies in the rapid growing stage unless the severity of the infection warrants it.