CLINICAL PHARMACOLOGY
Systemic Absorption
Absorption studies in humans with the ciprofloxacin ointment
have not been conducted, however, based on studies with
ciprofloxacin solution, 0.3%, mean maximal concentrations
are expected to be less than 2.5 ng/mL.
Microbiology
Ciprofloxacin has in vitro activity against a wide range
of gram-negative and gram-positive organisms. The bactericidal
action of ciprofloxacin results from interference with
the enzyme DNA gyrase which is needed for the synthesis
of bacterial DNA.
Ciprofloxacin has been shown to be active against most
strains of the following microorganisms both in vitro
and in clinical infections (See INDICATIONS section).
Aerobic gram-positive microorganisms:
Staphylococcus aureus (methicillin-susceptible strains)
Staphylococcus epidermidis (methicillin-susceptible
strains)
Streptococcus pneumoniae
Streptococcus Viridans Group
Aerobic gram-negative microorganisms:
Haemophilus influenzae
The following in vitro data are available; but their
clinical significance in ophthalmologic infections is unknown.
The safety and effectiveness of ciprofloxacin in treating
conjunctivitis due to these microorganisms have not been
established in adequate and well controlled trials.
The following organisms are considered susceptible when
evaluated using systemic breakpoints. However, a correlation
between the in vitro systemic breakpoint and ophthalmological
efficacy has not been established. Ciprofloxacin exhibits
in vitro minimal inhibitory concentrations (MIC’s)
of 1ng/mL or less (systemic susceptible breakpoint) against
most (³90%) strains of the following ocular pathogens.
Aerobic gram-positive microorganisms:
Bacillus species
Corynebacterium species
Staphylococcus haemolyticus
Staphylococcus hominis
Aerobic gram-negative microorganisms:
Acinetobacter calcoaceticus
Enterobacter aerogenes
Escherichia coil
Haemophilus parainfluenzae
Kiebsielle pneumoniae
Moraxella catarrhalis
Neisseria gonorrhoeae
Proteus mirabilis
Pseudomonas aeruginosa
Serratia marcesens
Most strains of Burkholderia cepacia and some strains of
Stenotrophomonas maltophilia are resistant to ciprofloxacin
as are most anaerobic bacteria, including Bacteroides fragilis
and Clostridium difficile.
The minimal bactericidal concentration (MBC) generally
does not exceed the minimal inhibitory concentration (MIC)
by more than a factor of 2. Resistance to ciprofloxacin
in vitro usually develops slowly (multiplestep mutation).
Ciprofloxacin does not cross-react with other antimicrobial
agents such as betalactams or aminoglycosides; therefore,
organisms resistant to these drugs may be susceptible
to ciprofloxacin. Organisms resistant to ciprofloxacin
may be susceptible to betalactams or aminogylcosides.
Clinical Studies
In multicenter clinical trials, approximately 75% of
the patients with signs and symptoms of bacterial conjunctivitis
and positive conjunctival cultures were clinically cured
and approximately 80% had presumed pathogens eradicated
by the end of treatment (day 7).
ANIMAL PHARMACOLOGY
Ciprofloxacin and related drugs have been shown to cause
arthropathy in immature animals of most species tested
following oral administration. However, a one month topical
ocular study using immature Beagle dogs did not demonstrate
any articular lesions.
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