Orbifloxacin (Orbax)
(for veterinary information only)
BRAND NAME: ORBAX
Available in 5.7 mg, 22.7 mg & 68 mg tablets
BACKGROUND
Until penicillin came on the scene in the 1940s, our efforts to combat bacterial
infection were largely ineffective. As different antibiotics were developed,
different types of bacteria were conquered, yet one bacterial species remained
seemingly invincible: Pseudomonas aeruginosa. Eventually antibiotics (the
aminoglycoside class) were developed that could kill Pseudomonas but they
were available only as injectable products and had potential to cause significant
kidney damage if used too long. With these kind of side effects and the ability
to treat Pseudomonas limited to hospitalized patients (where injections could
be given regularly), the battle with Pseudomonas was far from won.
A major breakthrough was the development of the fluoroquinolone class of
antibiotics (including enrofloxacin, its counterpart for human use ciprofloxacin,
and several 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.
Fluoroquinolones act by deactivating bacterial enzymes necessary for the
transcription of DNA. DNA is very 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.
Enrofloxacin, the first veterinary fluoroquinolone, enjoyed great success
on the market and was soon joined by orbifloxacin, marbofloxacin, and others.
Orbifloxacin has the following advantages:
Especially rapid absorption into the body after oral dosing (complete absorption
in 46 minutes)
Lower doses are generally necessary, which means fewer tablets to give and
often less expense (especially in larger dogs)
USES OF THIS MEDICATION
This medication may be used in either dogs or cats to combat different types
of infections, especially those involving Pseudomonas. Orbifloxacin is also
active against Staphylococci, and thus is commonly used for infections of
the skin.
SIDE EFFECTS
At approximately ten times the recommended dose vomiting and diarrhea may
be seen with this medication. At normal doses, this should not be seen. Dogs
with Pseudomonas ear infectionsrequire very high doses of orbifloxacin and
nausea may indeed become a problem.
In immature dogs (less than 8 months of age) damage to joint cartilage can
occur. This phenomenon is only seen in growing dogs and does not seem to
be a problem in cats. It is preferable not to use this medication in puppies
unless the severity of the infection present warrants it.
The use of enrofloxacin can produce crystals in urine. These crystals may
show up on a laboratory test thus it is important to be aware of this side
effect. While this has not been reported with orbifloxacin, there is no reason
to think that orbifloxacin cannot form crystals in urine as well.
The recently described problem with blindness in cats associated with higher
doses of enrofloxacin has not been reported in orbifloxacin.
INTERACTIONS WITH OTHER DRUGS
Sucralfate(a medication used to treat stomach ulcers) may bind orbifloxacin
and prevent it from entering the body. These medications should be given
at least 2 hours apart if they are used together.
Theophylline(an airway dilator) blood levels may be higher than usual if
this medication is used concurrently with orbifloxacin. The dose of theophylline
may need to be reduced.
If orbifloxacin 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 orbifloxacin and prevent absorption into the body. Such medications
should be separated from orbifloxacin by at least 2 hours.
CONCERNS AND CAUTIONS
Orbifloxacin tablets are enteric coated to hide the drug's naturally bitter
taste. If the tablets are crushed for some reason, the bitter taste is more
readily apparent. Crushing tablets to put in an animal's food is unlikely
to be an effective way to administer orbifloxacin.
Pseudomonas infections are especially common in ears. In this location, especially
high doses of orbifloxacin are needed to clear this infection.
Orbifloxacin should be avoided in pregnant, or nursing pets nor in immature
dogs unless the severity of the infection warrants it.
Orbifloxacin may lower the seizure threshhold (meaning that it can facilitate
seizures). This is not a problem for normal animals but fluoroquinolones
are best not used in animals with known seizure disorders.
It is our policy
not to give dosing information over the Internet.
Date
Published: 3/9/2001
Copyright
2001 - 2007 by the Veterinary Information Network, Inc. All rights reserved.
This work was originally published by Veterinary Information
Network, Inc. (VIN) and is republished with VIN's permission.