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CIPRO® I.V. (ciprofloxacin)
DESCRIPTION
CIPRO® I.V. (ciprofloxacin) is a synthetic broad-spectrum antimicrobial agent for intravenous (I.V.) administration. Ciprofloxacin, a fluoroquinolone, is 1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(1piperazinyl)-3-quinolinecarboxylic acid. Its empirical formula is C17H18FN3O3 and its chemical structure is:
Ciprofloxacin is a faint to light yellow crystalline powder with a molecular weight of 331.4. It is soluble in dilute (0.1N) hydrochloric acid and is practically insoluble in water and ethanol. CIPRO I.V. solutions are available as sterile 1% aqueous concentrates, which are intended for dilution prior to administration, and as 0.2% ready-for-use infusion solutions in 5% Dextrose Injection. All formulas contain lactic acid as a solubilizing agent and hydrochloric acid for pH adjustment. The pH range for the 1% aqueous concentrates in vials is 3.3 to 3.9. The pH range for the 0.2% ready-for-use infusion solutions is 3.5 to 4.6.
The plastic container is latex-free and is fabricated from a specially formulated polyvinyl chloride. Solutions in contact with the plastic container can leach out certain of its chemical components in very small amounts within the expiration period, e.g., di(2-ethylhexyl) phthalate (DEHP), up to 5 parts per million. The suitability of the plastic has been confirmed in tests in animals according to USP biological tests for plastic containers as well as by tissue culture toxicity studies.
CLINICAL PHARMACOLOGY
Absorption
Following 60-minute intravenous infusions of 200 mg and 400 mg ciprofloxacin to normal volunteers, the mean maximum serum concentrations achieved were 2.1 and 4.6 µg/mL, respectively; the concentrations at 12 hours were 0.1 and 0.2 µg/mL, respectively.
Steady-state Ciprofloxacin Serum Concentrations (µg/mL) After 60-minute I.V. Infusions q 12 h.
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Time after starting the infusion
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Dose
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30 min.
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1 hr
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3 hr
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6 hr
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8 hr
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12 hr
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200 mg
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1.7
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2.1
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0.6
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0.3
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0.2
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0.1
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400 mg
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3.7
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4.6
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1.3
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0.7
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0.5
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0.2
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The pharmacokinetics of ciprofloxacin are linear over the dose range of 200 to 400 mg administered intravenously. Comparison of the pharmacokinetic parameters following the 1st and 5th I.V. dose on a q 12 h regimen indicates no evidence of drug accumulation.
The absolute bioavailability of oral ciprofloxacin is within a range of 70–80% with no substantial loss by first pass metabolism. An intravenous infusion of 400-mg ciprofloxacin given over 60 minutes every 12 hours has been shown to produce an area under the serum concentration time curve (AUC) equivalent to that produced by a 500-mg oral dose given every 12 hours. An intravenous infusion of 400 mg ciprofloxacin given over 60 minutes every 8 hours has been shown to produce an AUC at steady-state equivalent to that produced by a 750-mg oral dose given every 12 hours. A 400-mg I.V. dose results in a Cmax similar to that observed with a 750-mg oral dose. An infusion of 200 mg ciprofloxacin given every 12 hours produces an AUC equivalent to that produced by a 250-mg oral dose given every 12 hours.
Steady-state Pharmacokinetic Parameter Following Multiple Oral and I.V. Doses
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Parameters
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500 mg
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400 mg
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750 mg
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400 mg
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q12h, P.O.
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q12h, I.V.
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q12h, P.O.
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q8h, I.V.
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AUC (µg•hr/mL)
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13.7 *
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12.7 *
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31.6 †
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32.9 ‡
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Cmax (µg/mL)
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2.97
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4.56
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3.59
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4.07
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Distribution
After intravenous administration, ciprofloxacin is present in saliva, nasal and bronchial secretions, sputum, skin blister fluid, lymph, peritoneal fluid, bile, and prostatic secretions. It has also been detected in the lung, skin, fat, muscle, cartilage, and bone. Although the drug diffuses into cerebrospinal fluid (CSF), CSF concentrations are generally less than 10% of peak serum concentrations. Levels of the drug in the aqueous and vitreous chambers of the eye are lower than in serum.
Metabolism
After I.V. administration, three metabolites of ciprofloxacin have been identified in human urine which together account for approximately 10% of the intravenous dose. The binding of ciprofloxacin to serum proteins is 20 to 40%. Ciprofloxacin is an inhibitor of human cytochrome P450 1A2 (CYP1A2) mediated metabolism. Coadministration of ciprofloxacin with other drugs primarily metabolized by CYP1A2 results in increased plasma concentrations of these drugs and could lead to clinically significant adverse events of the coadministered drug (see CONTRAINDICATIONS; WARNINGS; PRECAUTIONS: Drug Interactions).
Excretion
The serum elimination half-life is approximately 5–6 hours and the total clearance is around 35 L/hr. After intravenous administration, approximately 50% to 70% of the dose is excreted in the urine as unchanged drug. Following a 200-mg I.V. dose, concentrations in the urine usually exceed 200 µg/mL 0–2 hours after dosing and are generally greater than 15 µg/mL 8–12 hours after dosing. Following a 400-mg I.V. dose, urine concentrations generally exceed 400 µg/mL 0–2 hours after dosing and are usually greater than 30 µg/mL 8–12 hours after dosing. The renal clearance is approximately 22 L/hr. The urinary excretion of ciprofloxacin is virtually complete by 24 hours after dosing.
Although bile concentrations of ciprofloxacin are several fold higher than serum concentrations after intravenous dosing, only a small amount of the administered dose (< 1%) is recovered from the bile as unchanged drug. Approximately 15% of an I.V. dose is recovered from the feces within 5 days after dosing.
Special Populations
Pharmacokinetic studies of the oral (single dose) and intravenous (single and multiple dose) forms of ciprofloxacin indicate that plasma concentrations of ciprofloxacin are higher in elderly subjects (> 65 years) as compared to young adults. Although the Cmax is increased 16–40%, the increase in mean AUC is approximately 30%, and can be at least partially attributed to decreased renal clearance in the elderly. Elimination half-life is only slightly (~20%) prolonged in the elderly. These differences are not considered clinically significant. (See PRECAUTIONS: Geriatric Use.)
In patients with reduced renal function, the half-life of ciprofloxacin is slightly prolonged and dosage adjustments may be required. (See DOSAGE AND ADMINISTRATION.)
In preliminary studies in patients with stable chronic liver cirrhosis, no significant changes in ciprofloxacin pharmacokinetics have been observed. However, the kinetics of ciprofloxacin in patients with acute hepatic insufficiency have not been fully elucidated.
Following a single oral dose of 10 mg/kg ciprofloxacin suspension to 16 children ranging in age from 4 months to 7 years, the mean Cmax was 2.4 µg/mL (range: 1.5 – 3.4 µg/mL) and the mean AUC was 9.2 µg*h/mL (range: 5.8 – 14.9 µg*h/mL). There was no apparent age-dependence, and no notable increase in Cmax or AUC upon multiple dosing (10 mg/kg TID). In children with severe sepsis who were given intravenous ciprofloxacin (10 mg/kg as a 1-hour infusion), the mean Cmax was 6.1 µg/mL (range: 4.6 – 8.3 µg/mL) in 10 children less than 1 year of age; and 7.2 µg/mL (range: 4.7 – 11.8 µg/mL) in 10 children between 1 and 5 years of age. The AUC values were 17.4 µg*h/mL (range: 11.8 – 32 µg*h/mL) and 16.5 µg*h/mL (range: 11 – 23.8 µg*h/mL) in the respective age groups. These values are within the range reported for adults at therapeutic doses. Based on population pharmacokinetic analysis of pediatric patients with various infections, the predicted mean half-life in children is approximately 4 - 5 hours, and the bioavailability of the oral suspension is approximately 60%.
Drug-drug Interactions: Concomitant administration with tizanidine is contraindicated (See CONTRAINDICATIONS). The potential for pharmacokinetic drug interactions between ciprofloxacin and theophylline, caffeine, cyclosporins, phenytoin, sulfonylurea glyburide, metronidazole, warfarin, probenecid, and piperacillin sodium has been eva luated. (See WARNINGS: PRECAUTIONS: Drug Interactions.)
MICROBIOLOGY
Ciprofloxacin has in vitro activity against a wide range of gram-negative and gram-positive microorganisms. The bactericidal action of ciprofloxacin results from inhibition of the enzymes topoisomerase II (DNA gyrase) and topoisomerase IV, which are required for bacterial DNA replication, transcription, repair, and recombination. The mechanism of action of fluoroquinolones, including ciprofloxacin, is different from that of penicillins, cephalosporins, aminoglycosides, macrolides, and tetracyclines; therefore, microorganisms resistant to these classes of drugs may be susceptible to ciprofloxacin and other quinolones. There is no known cross-resistance between ciprofloxacin and other classes of antimicrobials. In vitro resistance to ciprofloxacin develops slowly by multiple step mutations.
Ciprofloxacin is slightly less active when tested at acidic pH. The inoculum size has little effect when tested in vitro. The minimal bactericidal concentration (MBC) generally does not exceed the minimal inhibitory concentration (MIC) by more than a factor of 2.
Ciprofloxacin has been shown to be active against most strains of the following microorganisms, both in vitro and in clinical infections as described in the INDICATIONS AND USAGE section of the package insert for CIPRO I.V. (ciprofloxacin for intravenous infusion).
Aerobic gram-positive microorganisms
Enterococcus faecalis (Many strains are only moderately susceptible.)
Staphylococcus aureus (methicillin-susceptible strains only)
Staphylococcus epidermidis (methicillin-susceptible strains only)
Staphylococcus saprophyticus
Streptococcus pneumoniae (penicillin-susceptible strains)
Streptococcus pyogenes
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Aerobic gram-negative microorganisms
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Citrobacter diversus
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Morganella morganii
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Citrobacter freundii
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Proteus mirabilis
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Enterobacter cloacae
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Proteus vulgaris
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Escherichia coli
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Providencia rettgeri
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Haemophilus influenzae
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Providencia stuartii
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Haemophilus parainfluenzae
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Pseudomonas aeruginosa
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Klebsiella pneumoniae
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Serratia marcescens
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Moraxella catarrhalis
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Ciprofloxacin has been shown to be active against Bacillus anthracis both in vitro and by use of serum levels as a surrogate marker (see INDICATIONS AND USAGE and INHALATIONAL ANTHRAX - ADDITIONAL INFORMATION).
The following in vitro data are available, but their clinical significance is unknown.
Ciprofloxacin exhibits in vitro minimum inhibitory concentrations (MICs) of 1 µg/mL or less against most (≥ 90%) strains of the following microorganisms; however, the safety and effectiveness of ciprofloxacin intravenous formulations in treating clinical infections due to these microorganisms have not been established in adequate and well-controlled clinical trials.
Aerobic gram-positive microorganisms
Staphylococcus haemolyticus
Staphylococcus hominis
Streptococcus pneumoniae (penicillin-resistant strains)
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Aerobic gram-negative microorganisms
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Acinetobacter Iwoffi
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Salmonella typhi
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Aeromonas hydrophila
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Shigella boydii
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Campylobacter jejuni
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Shigella dysenteriae
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Edwardsiella tarda
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Shigella flexneri
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Enterobacter aerogenes
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Shigella sonnei
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Klebsiella oxytoca
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Vibrio cholerae
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Legionella pneumophila
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Vibrio parahaemolyticus
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Neisseria gonorrhoeae
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Vibrio vulnificus
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Pasteurella multocida
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Yersinia enterocolitica
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Salmonella enteritidis
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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.
Susceptibility Tests
Dilution Techniques:
Quantitative methods are used to determine antimicrobial minimum inhibitory concentrations (MICs). These MICs provide estimates of the susceptibility of bacteria to antimicrobial compounds. The MICs should be determined using a standardized procedure. Standardized procedures are based on a dilution method1 (broth or agar) or equivalent with standardized inoculum concentrations and standardized concentrations of ciprofloxacin powder. The MIC values should be interpreted according to the following criteria:
For testing Enterobacteriaceae, Enterococcus faecalis, methicillin-susceptible Staphylococcus species, penicillin-susceptible Streptococcus pneumoniae, Streptococcus pyogenes, and Pseudomonas aeruginosaa :
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MIC (µg/mL)
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Interpretation
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≤ 1
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Susceptible (S)
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2
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Intermediate (I)
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≥ 4
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Resistant (R)
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a These interpretive standards are applicable only to broth microdilution susceptibility tests with streptococci using cation-adjusted Mueller-Hinton broth with 2–5% lysed horse blood.
For testing Haemophilus influenzae and Haemophilus parainfluenzae b:
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MIC (µg/mL)
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Interpretation
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≤ 1
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Susceptible (S)
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b This interpretive standard is applicable only to broth microdilution susceptibility tests with Haemophilus influenzae and Haemophilus parainfluenzae using Haemophilus Test Medium1.
The current absence of data on resistant strains precludes defining any results other than “Susceptible”. Strains yielding MIC results suggestive of a “nonsusceptible” category should be submitted to a reference laboratory for further testing.
A report of “Susceptible” indicates that the pathogen is likely to be inhibited if the antimicrobial compound in the blood reaches the concentrations usually achievable. A report of “Intermediate” indicates that the result should be considered equivocal, and, if the microorganism is not fully susceptible to alternative, clinically feasible drugs, the test should be repeated. This category implies possible clinical applicability in body sites where the drug is physiologically concentrated or in situations where high dosage of drug can be used. This category also provides a buffer zone, which prevents small uncontrolled technical factors from causing major discrepancies in interpretation. A report of “Resistant” indicates that the pathogen is not likely to be inhibited if the antimicrobial compound in the blood reaches the concentrations usually achievable; other therapy should be selected.
Standardized susceptibility test procedures require the use of laboratory control microorganisms to control the technical aspects of the laboratory procedures. Standard ciprofloxacin powder should provide the following MIC values:
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Organism
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MIC (µg/mL)
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E. faecalis
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ATCC 29212
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0.25 – 2
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E. coli
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ATCC 25922
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0.004 – 0.015
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H. influenzaea
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ATCC 49247
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0.004 – 0.03
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P. aeruginosa
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ATCC 27853
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0.25 – 1
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S. aureus
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ATCC 29213
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0.12 – 0.5
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a This quality control range is applicable to only H. influenzae ATCC 49247 tested by a broth microdilution procedure using Haemophilus Test Medium (HTM)1.
Diffusion Techniques:
Quantitative methods that require measurement of zone diameters also provide reproducible estimates of the susceptibility of bacteria to antimicrobial compounds. One such standardized procedure2 requires the use of standardized inoculum concentrations. This procedure uses paper disks impregnated with 5-µg ciprofloxacin to test the susceptibility of microorganisms to ciprofloxacin.
Reports from the laboratory providing results of the standard single-disk susceptibility test with a 5-µg ciprofloxacin disk should be interpreted according to the following criteria:
For testing Enterobacteriaceae, Enterococcus faecalis, methicillin-susceptible Staphylococcus species, penicillin-susceptible Streptococcus pneumoniae, Streptococcus pyogenes, and Pseudomonas aeruginosaa:
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Zone Diameter (mm)
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Interpretation
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≥ 21
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Susceptible (S)
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16 - 20
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Intermediate (I)
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≤ 15
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Resistant (R)
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a These zone diameter standards are applicable only to tests performed for streptococci using Mueller-Hinton agar supplemented with 5% sheep blood incubated in 5% CO2.
For testing Haemophilus influenzae and Haemophilus parainfluenzaeb:
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Zone Diameter (mm)
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Interpretation
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≥ 21
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Susceptible (S)
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b This zone diameter standard is applicable only to tests with Haemophilus influenzae and Haemophilus parainfluenzae using Haemophilus Test Medium (HTM)2.
The current absence of data on resistant strains precludes defining any results other than “Susceptible”. Strains yielding zone diameter results suggestive of a “nonsusceptible” category should be submitted to a reference laboratory for further testing.
Interpretation should be as stated above for results using dilution techniques. Interpretation involves correlation of the diameter obtained in the disk test with the MIC for ciprofloxacin.
As with standardized dilution techniques, diffusion methods require the use of laboratory control microorganisms that are used to control the technical aspects of the laboratory procedures. For the diffusion technique, the 5-µg ciprofloxacin disk should provide the following zone diameters in these laboratory test quality control strains:
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Organism
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Zone Diameter (mm)
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E. coli
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ATCC 25922
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30-40
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H. influenzaea
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ATCC 49247
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34-42
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P. aeruginosa
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ATCC 27853
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25-33
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S. aureus
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ATCC 25923
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22-30
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a These quality control limits are applicable to only H. influenzae ATCC 49247 testing using Haemophilus Test Medium (HTM)2.
INDICATIONS AND USAGE
CIPRO I.V. is indicated for the treatment of infections caused by susceptible strains of the designated microorganisms in the conditions and patient populations listed below when the intravenous administration offers a route of administration advantageous to the patient. Please see DOSAGE AND ADMINISTRATION for specific recommendations.
Adult Patients:
Urinary Tract Infections caused by Escherichia coli (including cases with secondary bacteremia), Klebsiella pneumoniae subspecies pneumoniae, Enterobacter cloacae, Serratia marcescens, Proteus mirabilis, Providencia rettgeri, Morganella morganii, Citrobacter diversus, Citrobacter freundii, Pseudomonas aeruginosa, methicillin-susceptible Staphylococcus epidermidis, Staphylococcus saprophyticus, or Enterococcus faecalis.
Lower Respiratory Infections caused by Escherichia coli, Klebsiella pneumoniae subspecies pneumoniae, Enterobacter cloacae, Proteus mirabilis, Pseudomonas aeruginosa, Haemophilus influenzae, Haemophilus parainfluenzae, or penicillin-susceptible Streptococcus pneumoniae. Also, Moraxella catarrhalis for the treatment of acute exacerbations of chronic bronchitis.
NOTE: Although effective in clinical trials, ciprofloxacin is not a drug of first choice in the treatment of presumed or confirmed pneumonia secondary to Streptococcus pneumoniae.
Nosocomial Pneumonia caused by Haemophilus influenzae or Klebsiella pneumoniae.
Skin and Skin Structure Infections caused by Escherichia coli, Klebsiella pneumoniae subspecies pneumoniae, Enterobacter cloacae, Proteus mirabilis, Proteus vulgaris, Providencia stuartii, Morganella morganii, Citrobacter freundii, Pseudomonas aeruginosa, methicillin-susceptible Staphylococcus aureus, methicillin-susceptible Staphylococcus epidermidis, or Streptococcus pyogenes.
Bone and Joint Infections caused by Enterobacter cloacae, Serratia marcescens, or Pseudomonas aeruginosa.
Complicated Intra-Abdominal Infections (used in conjunction with metronidazole) caused by Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, Klebsiella pneumoniae, or Bacteroides fragilis.
Acute Sinusitis caused by Haemophilus influenzae, penicillin-susceptible Streptococcus pneumoniae, or Moraxella catarrhalis.
Chronic Bacterial Prostatitis caused by Escherichia coli or Proteus mirabilis.
Empirical Therapy for Febrile Neutropenic Patients in combination with piperacillin sodium. (See CLINICAL STUDIES.)
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