Systemic Absorption:A systemic absorption study was performed in which Ciprofloxacin ophthalmic solution 0.3% was administered in each eye every two hours while awake for two days followed by every four hours while awake for an additional 5 days. The maximum reported plasma concentration of ciprofloxacin was less than 5 ng/mL. The mean concentration was usually less than 2.5 ng/mL.
Microbiology: Ciprofloxacin has
in vitroactivity 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 organisms both
in vitroand in clinical infections (
see INDICATIONS AND USAGE).
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
Pseudomonas aeruginosa
Serratia marcescens
Ciprofloxacin has been shown to be active
in vitroagainst most strains of the following organisms, however,
the clinical significance of these data is unknown:
Gram-Positive:
Enterococcus faecalis(Many strains are only moderately susceptible)
Staphylococcus haemolyticus
Staphylococcus hominis
Staphylococcus saprophyticus
Streptococcus pyogenes
Gram-Negative
Acinetobacter calcoaceticus subsp. anitratus
Aeromonas caviae
Aeromonas hydrophila
Brucella melitensis
Campylobacter coli
Campylobacter jejuni
Citrobacter diversus
Citrobacter freundii
Edwardsiella tarda
Enterobacter aerogenes
Enterobacter cloacae
Escherichia coli
Haemophilus ducreyi
Haemophilus parainfluenzae
Kiebsiella pneumoniae
Klebsiella oxytoca
Legionella pneumophila
Moraxella (Branhamella) catarrhalis
Morganella morganii
Neisseria gonorrhoeae
Neisseria meningitides
Pasteurella multocida
Proteus mirabilis
Proteus vulgaris
Providencia rettgeri
Providencia stuartii
Salmonella enteritidis
Salmonella typhi
Shigella sonneii
Shigella flexneri
Vibrio cholera
Vibrio parahaemolyticus
Vibrio vulnificus
Yersinia enterocolitica
Other Organisms:
Chlamydia trachomatis(only moderately susceptible) and
Mycobacterium tuberculosis(only moderately susceptible).
Most strains of
Pseudomonas cepaciaand some strains of
Pseudomonas maltophiliaare resistant to ciprofloxacin as are most anaerobic bacteria, including
Bacteroides fragilisand
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 vitrousually develops slowly (multiple-step mutation).
Ciprofloxacin does not cross-react with other antimicrobial agents such as beta-lactams or aminoglycosides; therefore, organisms resistant to these drugs may be susceptible to ciprofloxacin.