Absorption
Ciprofloxacin given as an oral tablet is rapidly and well
absorbed from the gastrointestinal tract after oral administration. The
absolute bioavailability is approximately 70% with no substantial loss by first
pass metabolism. Ciprofloxacin maximum serum concentrations and area under the
curve are shown in the chart for the 250 mg to 1000 mg dose range.
| Dose (mg) |
Maximum Serum Concentration
(μg/mL) |
Area Under Curve (AUC)
(μg•hr/mL) |
| 250 |
1.2 |
4.8 |
| 500 |
2.4 |
11.6 |
| 750 |
4.3 |
20.2 |
| 1000 |
5.4 |
30.8 |
Maximum serum concentrations are attained 1 to 2 hours after
oral dosing. Mean concentrations 12 hours after dosing with 250, 500, or 750 mg
are 0.1, 0.2, and 0.4 μg/mL, respectively. The serum elimination half-life
in subjects with normal renal function is approximately 4 hours. Serum
concentrations increase proportionately with doses up to 1000 mg.
A 500 mg oral dose given every 12 hours has been shown to
produce an area under the serum concentration time curve (AUC) equivalent to
that produced by an intravenous infusion of 400 mg ciprofloxacin given over 60
minutes every 12 hours. A 750 mg oral dose given every 12 hours has been shown
to produce an AUC at steady-state equivalent to that produced by an intravenous
infusion of 400 mg given over 60 minutes every 8 hours. A 750 mg oral dose
results in a Cmax similar to that observed with a 400 mg I.V. dose. A 250 mg
oral dose given every 12 hours produces an AUC equivalent to that produced by
an infusion of 200 mg ciprofloxacin given every 12 hours.
Steady-state Pharmacokinetic Parameters Following
Multiple Oral and I.V. Doses
| Parameters |
500 mg
q12h, P.O. |
400 mg
q12h, I.V. |
750 mg
q12h, P.O. |
400 mg
q8h, I.V. |
| AUC (μg•hr/mL) |
13.7a |
12.7a |
31.6b |
32.9c |
| Cmax (μg/mL) |
2.97 |
4.56 |
3.59 |
4.07 |
aAUC 0-12h
bAUC 24h=AUC0-12h x 2
cAUC 24h=AUC0-8h x 3 |
Distribution
The binding of ciprofloxacin to serum proteins is 20 to 40%
which is not likely to be high enough to cause significant protein binding
interactions with other drugs.
After oral administration, ciprofloxacin is widely
distributed throughout the body. Tissue concentrations often exceed serum
concentrations in both men and women, particularly in genital tissue including
the prostate. Ciprofloxacin is present in active form in the saliva, nasal and
bronchial secretions, mucosa of the sinuses, sputum, skin blister fluid, lymph,
peritoneal fluid, bile, and prostatic secretions. Ciprofloxacin has also been
detected in lung, skin, fat, muscle, cartilage, and bone. The drug diffuses
into the cerebrospinal fluid (CSF<); however, CSF concentrations are generally
less than 10% of peak serum concentrations. Low levels of the drug have been
detected in the aqueous and vitreous humors of the eye.
Metabolism
Four metabolites have been identified in human urine which together account
for approximately 15% of an oral dose. The metabolites have antimicrobial activity,
but are less active than unchanged ciprofloxacin. 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 in subjects with normal
renal function is approximately 4 hours. Approximately 40 to 50% of an orally
administered dose is excreted in the urine as unchanged drug. After a 250 mg
oral dose, urine concentrations of ciprofloxacin usually exceed 200 μg/mL
during the first two hours and are approximately 30 μg/mL at 8 to 12 hours
after dosing. The urinary excretion of ciprofloxacin is virtually complete
within 24 hours after dosing. The renal clearance of ciprofloxacin, which is
approximately 300 mL/minute, exceeds the normal glomerular filtration rate of
120 mL/minute. Thus, active tubular secretion would seem to play a significant
role in its elimination. Co-administration of probenecid with ciprofloxacin
results in about a 50% reduction in the ciprofloxacin renal clearance and a 50%
increase in its concentration in the systemic circulation. Although bile concentrations
of ciprofloxacin are several fold higher than serum concentrations after oral
dosing, only a small amount of the dose administered is recovered from the bile
as unchanged drug. An additional 1 to 2% of the dose is recovered from the bile
in the form of metabolites. Approximately 20 to 35% of an oral dose is
recovered from the feces within 5 days after dosing. This may arise from either
biliary clearance or transintestinal elimination.
With oral administration, a 500 mg dose, given as 10 mL of
the 5% CIPRO Suspension (containing 250 mg ciprofloxacin/5mL) is bioequivalent
to the 500 mg tablet. A 10 mL volume of the 5% CIPRO Suspension (containing 250
mg ciprofloxacin/5mL) is bioequivalent to a 5 mL volume of the 10% CIPRO
Suspension (containing 500 mg ciprofloxacin/5mL).
Drug-drug Interactions
When CIPRO Tablet is given concomitantly with food, there is
a delay in the absorption of the drug, resulting in peak concentrations that
occur closer to 2 hours after dosing rather than 1 hour whereas there is no
delay observed when CIPRO Suspension is given with food. The overall absorption
of CIPRO Tablet or CIPRO Suspension, however, is not substantially affected.
The pharmacokinetics of ciprofloxacin given as the suspension are also not
affected by food. Concurrent administration of antacids containing magnesium
hydroxide or aluminum hydroxide may reduce the bioavailability of ciprofloxacin
by as much as 90%. (See PRECAUTIONS.)
The serum concentrations of ciprofloxacin and metronidazole
were not altered when these two drugs were given concomitantly.
Concomitant administration with tizanidine is contraindicated (See CONTRAINDICATIONS).
Concomitant administration of ciprofloxacin with theophylline decreases the
clearance of theophylline resulting in elevated serum theophylline levels and
increased risk of a patient developing CNS or other adverse reactions. Ciprofloxacin
also decreases caffeine clearance and inhibits the formation of paraxanthine
after caffeine administration. (See WARNINGS,
PRECAUTIONS.)
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. 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. The kinetics of ciprofloxacin in patients with acute hepatic
insufficiency, however, 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 – 32.0 μg*h/mL) and 16.5
μg*h/mL (range: 11.0 – 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%.
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 (ciprofloxacin hydrochloride) Tablets and CIPRO (ciprofloxacin*)
5% and 10% Oral Suspension.
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 only)
Streptococcus pyogenes
Aerobic gram-negative microorganisms
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 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 only)
Aerobic gram-negative microorganisms
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:
| MIC (μg/mL) |
Interpretation |
| ≤ 1 |
Susceptible (S) |
| 2 |
Intermediate (I) |
| ≥ 4 |
Resistant (R) |
| aThese 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
parainfluenzaeb:
| MIC (μg/mL) |
Interpretation |
| ≤ 1 |
Susceptible (S) |
| 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.
For testing Neisseria gonorrhoeaec:
| MIC (μg/mL) |
Interpretation |
| ≤ 0.06 |
Susceptible (S) |
| 0.12 – 0.5 |
Intermediate (I) |
| ≥ 1 |
Resistant (R) |
| c This interpretive standard is applicable only to agar dilution test with GC agar base and 1% defined growth supplement. |
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:
| Organism |
|
MIC (μg/mL) |
| E. faecalis |
ATCC 29212 |
0.25 – 2 |
| E. coli |
ATCC 25922 |
0.004 – 0.015 |
| H. influenzaea |
ATCC 49247 |
0.004 – 0.03 |
| P. aeruginosa |
ATCC 27853 |
0.25 – 1.0 |
| S. aureus |
ATCC 29213 |
0.12 – 0.5 |
| C. jejunib |
ATCC 33560 |
0.06 – 0.25 and 0.03 – 0.12 |
| N. gonorrhoeaec |
ATCC 49226 |
0.001-0.008 |
aThis quality control range is
applicable to only H. influenzae ATCC 49247 tested by a broth microdilution
procedure using Haemophilus Test Medium (HTM)1.
b C. jejuni ATCC 33560 tested by broth microdilution
procedure using cation adjusted Mueller Hinton broth with 2.5-5% lysed
horse blood in a microaerophilic environment at 36-37°C for 48 hours
and for 42°C at 24 hours2, respectively.
c N. gonorrhoeae ATCC 49226 tested by agar dilution
procedure using GC agar and 1% defined growth supplement in a 5% CO2
environment at 35-37°C for 20-24 hours3. |
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 procedure3
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
:
| Zone Diameter (mm) |
Interpretation |
| ≥ 21 |
Susceptible (S) |
| 16 – 20 |
Intermediate (I) |
| ≤ 15 |
Resistant (R) |
| 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:
| Zone Diameter (mm) |
Interpretation |
| ≥ 21 |
Susceptible (S) |
| bThis zone diameter standard is applicable only to tests with Haemophilus influenzae and Haemophilus parainfluenzae using Haemophilus Test Medium (HTM)3. |
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.
For testing Neisseria gonorrhoeaec:
| Zone Diameter (mm) |
Interpretation |
| ≥ 41 |
Susceptible (S) |
| 28 – 40 |
Intermediate (I) |
| ≤ 27 |
Resistant (R) |
| cThis zone diameter standard is applicable only to disk diffusion tests with GC agar base and 1% defined growth supplement. |
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:
| Organism |
|
Zone Diameter (mm) |
| E. coli |
ATCC 25922 |
30 – 40 |
| H. influenzaea |
ATCC 49247 |
34 – 42 |
| N. gonorrhoeaeb |
ATCC 49226 |
48 – 58 |
| P. aeruginosa |
ATCC 27853 |
25 – 33 |
| S. aureus |
ATCC 25923 |
22 – 30 |
a These quality control limits
are applicable to only H. influenzae ATCC 49247 testing using Haemophilus
Test Medium (HTM)3.
b These quality control limits are applicable only to tests
conducted with N. gonorrhoeae ATCC 49226 performed by disk diffusion
using GC agar base and 1% defined growth supplement. |
Animal Pharmacology
Ciprofloxacin and other quinolones have been shown to cause
arthropathy in immature animals of most species tested. (See WARNINGS.)
Damage of weight bearing joints was observed in juvenile dogs and rats. In
young beagles, 100 mg/kg ciprofloxacin, given daily for 4 weeks, caused degenerative
articular changes of the knee joint. At 30 mg/kg, the effect on the joint was
minimal. In a subsequent study in young beagle dogs, oral ciprofloxacin doses
of 30 mg/kg and 90 mg/kg ciprofloxacin (approximately 1.3- and 3.5-times the
pediatric dose based upon comparative plasma AUCs) given daily for 2 weeks
caused articular changes which were still observed by histopathology after a
treatment-free period of 5 months. At 10 mg/kg (approximately 0.6-times the
pediatric dose based upon comparative plasma AUCs), no effects on joints were
observed. This dose was also not associated with arthrotoxicity after an
additional treatment-free period of 5 months. In another study, removal of
weight bearing from the joint reduced the lesions but did not totally prevent
them.
Crystalluria, sometimes associated with secondary
nephropathy, occurs in laboratory animals dosed with ciprofloxacin. This is
primarily related to the reduced solubility of ciprofloxacin under alkaline
conditions, which predominate in the urine of test animals; in man,
crystalluria is rare since human urine is typically acidic. In rhesus monkeys,
crystalluria without nephropathy was noted after single oral doses as low as 5 mg/kg.
(approximately 0.07-times the highest recommended therapeutic dose based upon mg/m²).
After 6 months of intravenous dosing at 10 mg/kg/day, no nephropathological
changes were noted; however, nephropathy was observed after dosing at 20
mg/kg/day for the same duration (approximately 0.2-times the highest
recommended therapeutic dose based upon mg/m²).
In dogs, ciprofloxacin at 3 and 10 mg/kg by rapid I.V.
injection (15 sec.) produces pronounced hypotensive effects. These effects are
considered to be related to histamine release, since they are partially
antagonized by pyrilamine, an antihistamine. In rhesus monkeys, rapid I.V.
injection also produces hypotension but the effect in this species is
inconsistent and less pronounced.
In mice, concomitant administration of nonsteroidal
anti-inflammatory drugs such as phenylbutazone and indomethacin with quinolones
has been reported to enhance the CNS stimulatory effect of quinolones.
Ocular toxicity seen with some related drugs has not been
observed in ciprofloxacin-treated animals.
Clinical Studies
Complicated Urinary Tract Infection and Pyelonephritis – Efficacy in Pediatric
Patients
NOTE: Although effective in clinical trials, ciprofloxacin
is not a drug of first choice in the pediatric population due to an increased
incidence of adverse events compared to controls, including events related to
joints and/or surrounding tissues.
Ciprofloxacin, administered I.V. and/or orally, was compared
to a cephalosporin for treatment of complicated urinary tract infections (cUTI)
and pyelonephritis in pediatric patients 1 to 17 years of age (mean age of 6 ±
4 years). The trial was conducted in the US, Canada, Argentina, Peru, Costa Rica, Mexico, South Africa, and Germany. The duration of therapy was 10 to 21 days (mean
duration of treatment was 11 days with a range of 1 to 88 days). The primary objective
of the study was to assess musculoskeletal and neurological safety.
Patients were evaluated for clinical success and
bacteriological eradication of the baseline organism(s) with no new infection
or superinfection at 5 to 9 days post-therapy (Test of Cure or TOC). The Per
Protocol population had a causative organism(s) with protocol specified colony count(s)
at baseline, no protocol violation, and no premature discontinuation or loss to
follow-up (among other criteria).
The clinical success and bacteriologic eradication rates in
the Per Protocol population were similar between ciprofloxacin and the
comparator group as shown below.
Clinical Success and Bacteriologic Eradication at Test of
Cure (5 to 9 Days Post-Therapy)
| |
CIPRO |
Comparator |
| Randomized Patients |
337 |
352 |
| Per Protocol Patients |
211 |
231 |
| Clinical Response at 5 to 9 Days Post-Treatment |
95.7% (202/211) |
92.6% (214/231) |
| |
95% CI [-1.3%, 7.3%] |
| Bacteriologic Eradication by |
84.4% (178/211) |
78.3% (181/231) |
| Patient at 5 to 9 Days |
|
|
| Post-Treatment* |
|
|
| |
95% CI [ -1.3%, 13.1%] |
| Bacteriologic Eradication of the Baseline Pathogen at 5 to 9 Days Post-Treatment |
|
|
| Escherichia coli |
156/178 (88%) |
161/179 (90%) |
| * Patients with baseline pathogen(s) eradicated and no new infections or superinfections/total number of patients. There were 5.5% (6/211) ciprofloxacin and 9.5% (22/231) comparator patients with superinfections or new infections. |
Inhalational Anthrax In Adults And Pediatrics Additional Information
The mean serum concentrations of ciprofloxacin associated with a statistically
significant improvement in survival in the rhesus monkey model of inhalational
anthrax are reached or exceeded in adult and pediatric patients receiving oral
and intravenous regimens. (See DOSAGE AND ADMINISTRATION.)
Ciprofloxacin pharmacokinetics have been evaluated in various human populations.
The mean peak serum concentration achieved at steady-state in human adults receiving
500 mg orally every 12 hours is 2.97 μg/mL, and 4.56 μg/mL following 400
mg intravenously every 12 hours. The mean trough serum concentration at steady-state
for both of these regimens is 0.2 μg/mL. In a study of 10 pediatric patients
between 6 and 16 years of age, the mean peak plasma concentration achieved is
8.3 μg/mL and trough concentrations range from 0.09 to 0.26 μg/mL, following
two 30-minute intravenous infusions of 10 mg/kg administered 12 hours apart.
After the second intravenous infusion patients switched to 15 mg/kg orally every
12 hours achieve a mean peak concentration of 3.6 μg/mL after the initial
oral dose. Long-term safety data, including effects on cartilage, following
the administration of ciprofloxacin to pediatric patients are limited. (For
additional information, see PRECAUTIONS,
Pediatric Use.) Ciprofloxacin serum concentrations achieved in humans serve
as a surrogate endpoint reasonably likely to predict clinical benefit and provide
the basis for this indication.5
A placebo-controlled animal study in rhesus monkeys exposed
to an inhaled mean dose of 11 LD50 (~5.5 x 105 spores (range 5-30 LD50)
of B. anthracis was conducted. The minimal inhibitory concentration
(MIC) of ciprofloxacin for the anthrax strain used in this study was 0.08 μg/mL.
In the animals studied, mean serum concentrations of ciprofloxacin achieved at
expected Tmax (1 hour post-dose) following oral dosing to steady-state ranged
from 0.98 to 1.69 μg/mL. Mean steady-state trough concentrations at 12
hours post-dose ranged from 0.12 to 0.19 μg/mL.6 Mortality due to anthrax for
animals that received a 30-day regimen of oral ciprofloxacin beginning 24 hours
post-exposure was significantly lower (1/9), compared to the placebo group
(9/10) [p= 0.001]. The one ciprofloxacin-treated animal that died of anthrax
did so following the 30-day drug administration period.7
More than 9300 persons were recommended to complete a
minimum of 60 days of antibiotic prophylaxis against possible inhalational
exposure to B. anthracis during 2001. Ciprofloxacin was recommended to
most of those individuals for all or part of the prophylaxis regimen. Some persons
were also given anthrax vaccine or were switched to alternative antibiotics. No
one who received ciprofloxacin or other therapies as prophylactic treatment
subsequently developed inhalational anthrax. The number of persons who received
ciprofloxacin as all or part of their post-exposure prophylaxis regimen is
unknown.
Among the persons surveyed by the Centers for Disease
Control and Prevention, over 1000 reported receiving ciprofloxacin as sole
post-exposure prophylaxis for inhalational anthrax. Gastrointestinal adverse
events (nausea, vomiting, diarrhea, or stomach pain), neurological adverse
events (problems sleeping, nightmares, headache, dizziness or lightheadedness)
and musculoskeletal adverse events (muscle or tendon pain and joint swelling or
pain) were more frequent than had been previously reported in controlled
clinical trials. This higher incidence, in the absence of a control group,
could be explained by a reporting bias, concurrent medical conditions, other
concomitant medications, emotional stress or other confounding factors, and/or
a longer treatment period with ciprofloxacin. Because of these factors and
limitations in the data collection, it is difficult to evaluate whether the
reported symptoms were drug-related.
Last updated on RxList: 5/12/2009