Cefepime is an antibacterial agent belonging to the cephalosporin class of
antibacterials with in vitro antibacterial activity against facultative
Gram-positive and Gram-negative bacteria.
Pharmacokinetics
The average plasma concentrations of cefepime observed in healthy adult male volunteers (n=9) at various times following single 30-minute infusions (IV) of cefepime 500 mg, 1 g, and 2 g are summarized in Table 1. Elimination of cefepime is principally via renal excretion with an average ( ± SD) half-life of 2.0 ( ± 0.3) hours and total body clearance of 120.0 ( ± 8.0) mL/min in healthy volunteers. Cefepime pharmacokinetics are linear over the range 250 mg to 2 g. There is no evidence of accumulation in healthy adult male volunteers (n=7) receiving clinically relevant doses for a period of 9 days.
Absorption
The average plasma concentrations of cefepime and its derived pharmacokinetic parameters after intravenous (IV) administration are portrayed in Table 1.
Table 1: Average Plasma Concentrations in mcg/mL of Cefepime
and Derived Pharmacokinetic Parameters ( ± SD), Intravenous Administration
| Parameter |
MAXIPIME |
| 500 mg IV |
1 g IV |
2 g IV |
| 0.5 h |
38.2 |
78.7 |
163.1 |
| 1 h |
21.6 |
44.5 |
85.8 |
| 2 h |
11.6 |
24.3 |
44.8 |
| 4 h |
5.0 |
10.5 |
19.2 |
| 8 h |
1.4 |
2.4 |
3.9 |
| 12 h |
0.2 |
0.6 |
1.1 |
| Cmax, mcg/mL |
39.1 (3.5) |
81.7 (5.1) |
163.9 (25.3) |
| AUC, h•mcg/mL |
70.8 (6.7) |
148.5 (15.1) |
284.8 (30.6) |
| Number of subjects (male) |
9 |
9 |
9 |
Following intramuscular (IM) administration, cefepime is completely absorbed. The average plasma concentrations of cefepime at various times following a single intramuscular injection are summarized in Table 2. The pharmacokinetics of cefepime are linear over the range of 500 mg to 2 g intramuscularly and do not vary with respect to treatment duration.
Table 2: Average Plasma Concentrations in mcg/mL of Cefepime
and Derived Pharmacokinetic Parameters ( ± SD), Intramuscular Administration
| Parameter |
MAXIPIME |
| 500 mg IM |
1 g IM |
2 g IM |
| 0.5 h |
8.2 |
14.8 |
36.1 |
| 1 h |
12.5 |
25.9 |
49.9 |
| 2 h |
12.0 |
26.3 |
51.3 |
| 4 h |
6.9 |
16.0 |
31.5 |
| 8 h |
1.9 |
4.5 |
8.7 |
| 12 h |
0.7 |
1.4 |
2.3 |
| Cmax, mcg/mL |
13.9 (3.4) |
29.6 (4.4) |
57.5 (9.5) |
| Tmax, h |
1.4 (0.9) |
1.6 (0.4) |
1.5 (0.4) |
| AUC, h•mcg/mL |
60 (8) |
137 (11) |
262 (23) |
| Number of subjects (male) |
6 |
6 |
12 |
Distribution
The average steady-state volume of distribution of cefepime is 18.0 ( ± 2.0) L. The serum protein binding of cefepime is approximately 20% and is independent of its concentration in serum.
Cefepime is excreted in human milk. A nursing infant consuming approximately
1000 mL of human milk per day would receive approximately 0.5 mg of cefepime
per day. (See PRECAUTIONS: Nursing Mothers.)
Concentrations of cefepime achieved in specific tissues and body fluids are listed in Table 3.
Table 3: Average Concentrations of Cefepime in Specific Body
Fluids (mcg/mL) or Tissues (mcg/g)
| Tissue or Fluid |
Dose/Route |
# of Patients |
Average Time of Sample Post-Dose (h) |
Average Concentration |
| Blister Fluid |
2 g IV |
6 |
1.5 |
81.4 mcg/mL |
| Bronchial Mucosa |
2 g IV |
20 |
4.8 |
24.1 mcg/g |
| Sputum |
2 g IV |
5 |
4.0 |
7.4 mcg/mL |
| Urine |
500 mg IV |
8 |
0–4 |
292 mcg/mL |
| 1 g IV |
12 |
0–4 |
926 mcg/mL |
| 2 g IV |
12 |
0–4 |
3120 mcg/mL |
| Bile |
2 g IV |
26 |
9.4 |
17.8 mcg/mL |
| Peritoneal Fluid |
2 g IV |
19 |
4.4 |
18.3 mcg/mL |
| Appendix |
2 g IV |
31 |
5.7 |
5.2 mcg/g |
| Gallbladder |
2 g IV |
38 |
8.9 |
11.9 mcg/g |
| Prostate |
2 g IV |
5 |
1.0 |
31.5 mcg/g |
Data suggest that cefepime does cross the inflamed blood-brain barrier. The
clinical relevance of these data is uncertain at this time.
Metabolism and Excretion
Cefepime is metabolized to N-methylpyrrolidine (NMP) which is rapidly converted
to the N-oxide (NMP-N-oxide). Urinary recovery of unchanged cefepime accounts
for approximately 85% of the administered dose. Less than 1% of the administered
dose is recovered from urine as NMP, 6.8% as NMP-N-oxide, and 2.5% as an epimer
of cefepime. Because renal excretion is a significant pathway of elimination,
patients with renal dysfunction and patients undergoing hemodialysis require
dosage adjustment. (See DOSAGE AND ADMINISTRATION.)
Specific Populations
Renal impairment: Cefepime pharmacokinetics have been investigated
in patients with various degrees of renal impairment (n=30). The average half-life
in patients requiring hemodialysis was 13.5 ( ± 2.7) hours and in patients
requiring continuous peritoneal dialysis was 19.0 ( ± 2.0) hours. Cefepime
total body clearance decreased proportionally with creatinine clearance in patients
with abnormal renal function, which serves as the basis for dosage adjustment
recommendations in this group of patients. (See DOSAGE
AND ADMINISTRATION.)
Hepatic impairment: The pharmacokinetics of cefepime were unaltered
in patients with hepatic impairment who received a single 1 g dose (n=11).
Geriatric patients: Cefepime pharmacokinetics have been investigated
in elderly (65 years of age and older) men (n=12) and women (n=12) whose mean
(SD) creatinine clearance was 74.0 ( ± 15.0) mL/min. There appeared to
be a decrease in cefepime total body clearance as a function of creatinine clearance.
Therefore, dosage administration of cefepime in the elderly should be adjusted
as appropriate if the patient's creatinine clearance is 60 mL/min or less. (See
DOSAGE AND ADMINISTRATION.)
Pediatric patients: Cefepime pharmacokinetics have been evaluated
in pediatric patients from 2 months to 11 years of age following single and
multiple doses on every 8 hours (n=29) and every 12 hours (n=13) schedules.
Following a single intravenous dose, total body clearance and the steady-state
volume of distribution averaged 3.3 ( ± 1.0) mL/min/kg and 0.3 ( ± 0.1)
L/kg, respectively. The urinary recovery of unchanged cefepime was 60.4 ( ± 30.4)%
of the administered dose, and the average renal clearance was 2.0 ( ± 1.1)
mL/min/kg. There were no significant effects of age or gender (25 male vs 17
female) on total body clearance or volume of distribution, corrected for body
weight. No accumulation was seen when cefepime was given at 50 mg per kg every
12 hours (n=13), while Cmax, AUC, and t½ were increased about 15% at steady
state after 50 mg per kg every 8 hours. The exposure to cefepime following a
50 mg per kg intravenous dose in a pediatric patient is comparable to that in
an adult treated with a 2 g intravenous dose. The absolute bioavailability of
cefepime after an intramuscular dose of 50 mg per kg was 82.3 ( ± 15)%
in eight patients.
Microbiology
Cefepime is a bactericidal agent that acts by inhibition of bacterial cell
wall synthesis. Cefepime has a broad spectrum of in vitro activity that
encompasses a wide range of Gram-positive and Gram-negative bacteria. Cefepime
has a low affinity for chromosomally-encoded beta-lactamases. Cefepime is highly
resistant to hydrolysis by most beta-lactamases and exhibits rapid penetration
into Gram-negative bacterial cells. Within bacterial cells, the molecular targets
of cefepime are the penicillin binding proteins (PBP).
Cefepime has been shown to be active against most isolates of the following
microorganisms, both in vitro and in clinical infections as described
in the INDICATIONS section.
Aerobic Gram-Negative Microorganisms:
Enterobacter
Escherichia coli
Klebsiella pneumoniae
Proteus mirabilis
Pseudomonas aeruginosa
Aerobic Gram-Positive Microorganisms:
Staphylococcus aureus (methicillin-susceptible isolates only)
Streptococcus pneumoniae
Streptococcus pyogenes (Lancefield's Group A streptococci)
Viridans group streptococci
The following in vitro data are available, but their clinical significance
is unknown.
Cefepime has been shown to have in vitro activity against most isolates
of the following microorganisms; however, the safety and effectiveness of cefepime
in treating clinical infections due to these microorganisms have not been established
in adequate and well-controlled trials.
Aerobic Gram-Positive Microorganisms:
Staphylococcus epidermidis (methicillin-susceptible isolates only)
Staphylococcus saprophyticus
Streptococcus agalactiae (Lancefield's Group B streptococci)
NOTE: Most isolates of enterococci, eg, Enterococcus faecalis, and methicillin-resistant
staphylococci are resistant to cefepime.
Aerobic Gram-Negative Microorganisms:
Acinetobacter calcoaceticus subsp. lwoffii
Citrobacter diversus
Citrobacter freundii
Enterobacter agglomerans
Haemophilus influenzae (including beta-lactamase producing isolates)
Hafnia alvei
Klebsiella oxytoca
Moraxella catarrhalis (including beta-lactamase producing isolates)
Morganella morganii
Proteus vulgaris
Providencia rettgeri
Providencia stuartii
Serratia marcescens
NOTE: Cefepime is inactive against many isolates of Stenotrophomonas
(formerly Xanthomonas maltophilia and Pseudomonas maltophilia).
Anaerobic Microorganisms:
NOTE: Cefepime is inactive against most isolates of 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 cefepime powder. The MIC values should be interpreted
according to the following criteria:
Table 4
| Microorganism |
MIC (mcg/mL) |
| Susceptible (S) |
Intermediate (I) |
Resistant (R) |
| Microorganisms other than Haemophilus spp.* and Streptococcus
pneumoniae* |
≤8 |
16 |
≥32 |
| Haemophilus spp.* |
≤2 |
—* |
—* |
| S. pneumoniae* |
≤0.5 |
1 |
≥2 |
*NOTE: Isolates from these species should be tested for susceptibility
using specialized dilution testing methods.1
Also, isolates of Haemophilus spp. with MICs greater than 2 mcg/mL
should be considered equivocal and should be further evaluated. |
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. Laboratory control microorganisms are specific strains of microbiological assay organisms with intrinsic biological properties relating to resistance mechanisms and their genetic expression within bacteria; the specific strains are not clinically significant in their current microbiological status. Standard cefepime powder should provide the following MIC values (Table 5) when tested against the designated quality control strains:
Table 5
| Microorganism |
ATCC |
MIC (mcg/mL) |
| Escherichia coli |
25922 |
0.016–0.12 |
| Staphylococcus aureus |
29213 |
1–4 |
| Pseudomonas aeruginosa |
27853 |
1–4 |
| Haemophilus influenzae |
49247 |
0.5–2 |
| Streptococcus pneumoniae |
49619 |
0.06–0.25 |
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 30
mcg of cefepime to test the susceptibility of microorganisms to cefepime. Interpretation
is identical to that stated above for results using dilution techniques.
Reports from the laboratory providing results of the standard single-disk susceptibility test with a 30-mcg cefepime disk should be interpreted according to the following criteria:
Table 6
| Microorganism |
Zone Diameter (mm) |
| Susceptible (S) |
Intermediate (I) |
Resistant (R) |
| Microorganisms other than Haemophilus spp.* and S. pneumoniae* |
≥18 |
15–17 |
≤14 |
| Haemophilus spp.* |
≥26 |
—* |
—* |
*NOTE: Isolates from these species should be tested for susceptibility
using specialized diffusion testing methods.2
Isolates of Haemophilus spp. with zones smaller than 26 mm should
be considered equivocal and should be further evaluated. Isolates of S.
pneumoniae should be tested against a 1-mcg oxacillin disk; isolates
with oxacillin zone sizes larger than or equal to 20 mm may be considered
susceptible to cefepime. |
As with standardized dilution techniques, diffusion methods require the use of laboratory control microorganisms to control the technical aspects of the laboratory procedures. Laboratory control microorganisms are specific strains of microbiological assay organisms with intrinsic biological properties relating to resistance mechanisms and their genetic expression within bacteria; the specific strains are not clinically significant in their current microbiological status. For the diffusion technique, the 30-mcg cefepime disk should provide the following zone diameters in these laboratory test quality control strains (Table 7):
Table 7
| Microorganism |
ATCC |
Zone Size Range (mm) |
| Escherichia coli |
25922 |
29–35 |
| Staphylococcus aureus |
25923 |
23–29 |
| Pseudomonas aeruginosa |
27853 |
24–30 |
| Haemophilus influenzae |
49247 |
25–31 |
Clinical Studies
Febrile Neutropenic Patients
The safety and efficacy of empiric cefepime monotherapy of febrile neutropenic patients have been assessed in two multicenter, randomized trials comparing cefepime monotherapy (at a dose of 2 g intravenously every 8 hours) to ceftazidime monotherapy (at a dose of 2 g intravenously every 8 hours). These studies comprised 317 evaluable patients. Table 8 describes the characteristics of the evaluable patient population.
Table 8: Demographics of Evaluable Patients (First Episodes
Only)
| Total |
Cefepime |
Ceftazidime |
| 164 |
153 |
| Median age (yr) |
56.0 (range, 18–82) |
55.0 (range, 16–84) |
| Male |
86 (52%) |
85 (56%) |
| Female |
78 (48%) |
68 (44%) |
| Leukemia |
65 (40%) |
52 (34%) |
| Other hematologic malignancies |
43 (26%) |
36 (24%) |
| Solid tumor |
54 (33%) |
56 (37%) |
| Median ANC nadir (cells/microliter) |
20 (range, 0–500) |
20 (range, 0–500) |
| Median duration of neutropenia (days) |
6 (range, 0–39) |
6 (range, 0–32) |
| Indwelling venous catheter |
97 (59%) |
86 (56%) |
| Prophylactic antibiotics |
62 (38%) |
64 (42%) |
| Bone marrow graft |
9 (5%) |
7 (5%) |
| SBP less than 90 mm Hg at entry |
7 (4%) |
2 (1%) |
| ANC = absolute neutrophil count; SBP = systolic blood pressure
|
Table 9 describes the clinical response rates observed. For all outcome measures, cefepime was therapeutically equivalent to ceftazidime.
Table 9: Pooled Response Rates for Empiric Therapy of Febrile
Neutropenic Patients
| Outcome Measures |
% Response |
Cefepime
(n=164) |
Ceftazidime
(n=153) |
| Primary episode resolved with no treatment modification, no new febrile
episodes or infection, and oral antibiotics allowed for completion of treatment |
51 |
55 |
| Primary episode resolved with no treatment modification, no new febrile
episodes or infection and no post-treatment oral antibiotics |
34 |
39 |
| Survival, any treatment modification allowed |
93 |
97 |
| Primary episode resolved with no treatment modification and oral antibiotics
allowed for completion of treatment |
62 |
67 |
| Primary episode resolved with no treatment modification and no post-treatment
oral antibiotics |
46 |
51 |
Insufficient data exist to support the efficacy of cefepime monotherapy in patients at high risk for severe infection (including patients with a history of recent bone marrow transplantation, with hypotension at presentation, with an underlying hematologic malignancy, or with severe or prolonged neutropenia). No data are available in patients with septic shock.
Complicated Intra-Abdominal Infections
Patients hospitalized with complicated intra-abdominal infections participated in a randomized, double-blind, multicenter trial comparing the combination of cefepime (2 g every 12 hours) plus intravenous metronidazole (500 mg every 6 hours) versus imipenem/cilastatin (500 mg every 6 hours) for a maximum duration of 14 days of therapy. The study was designed to demonstrate equivalence of the two therapies. The primary analyses were conducted on the protocol-valid population, which consisted of those with a surgically confirmed complicated infection, at least one pathogen isolated pretreatment, at least 5 days of treatment, and a 4 to 6 week follow-up assessment for cured patients. Subjects in the imipenem/cilastatin arm had higher APACHE II scores at baseline. The treatment groups were otherwise generally comparable with regard to their pretreatment characteristics. The overall clinical cure rate among the protocol-valid patients was 81% (51 cured/63 evaluable patients) in the cefepime plus metronidazole group and 66% (62/94) in the imipenem/cilastatin group. The observed differences in efficacy may have been due to a greater proportion of patients with high APACHE II scores in the imipenem/cilastatin group.
REFERENCES
1. National Committee for Clinical Laboratory Standards. Methods for Dilution
Antimicrobial Susceptibility Tests for Bacteria that Grow Aerobically—Third
Edition. Approved Standard NCCLS Document M7-A3, Vol. 13, No. 25, NCCLS, Villanova,
PA, December 1993.
2. National Committee for Clinical Laboratory Standards. Performance
Standards for Antimicrobial Disk Susceptibility Tests—Fifth Edition. Approved
Standard NCCLS Document M2-A5, Vol. 13, No. 24, NCCLS, Villanova, PA, December
1993.
3. Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine.
Nephron. 1976; 16:31-41.
Last updated on RxList: 10/13/2009