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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.

Last reviewed on RxList: 12/8/2004
This monograph has been modified to include the generic and brand name in many instances.