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CLINICAL PHARMACOLOGY

After intramuscular (IM) injection of a 750-mg dose of cefuroxime to normal volunteers, the mean peak serum concentration was 27 mcg/mL. The peak occurred at approximately 45 minutes (range, 15 to 60 minutes). Following IV doses of 750 mg and 1.5 g, serum concentrations were approximately 50 and 100 mcg/mL, respectively, at 15 minutes. Therapeutic serum concentrations of approximately 2 mcg/mL or more were maintained for 5.3 hours and 8 hours or more, respectively. There was no evidence of accumulation of cefuroxime in the serum following IV administration of 1.5-g doses every 8 hours to normal volunteers. The serum half-life after either IM or IV injections is approximately 80 minutes.

Approximately 89% of a dose of cefuroxime is excreted by the kidneys over an 8-hour period, resulting in high urinary concentrations.

Following the IM administration of a 750-mg single dose, urinary concentrations averaged 1,300 mcg/mL during the first 8 hours. Intravenous doses of 750 mg and 1.5 g produced urinary levels averaging 1,150 and 2,500 mcg/mL, respectively, during the first 8-hour period.

The concomitant oral administration of probenecid with cefuroxime slows tubular secretion, decreases renal clearance by approximately 40%, increases the peak serum level by approximately 30%, and increases the serum half-life by approximately 30%. Cefuroxime is detectable in therapeutic concentrations in pleural fluid, joint fluid, bile, sputum, bone, and aqueous humor.

Cefuroxime is detectable in therapeutic concentrations in cerebrospinal fluid (CSF) of adults and pediatric patients with meningitis. The following table shows the concentrations of cefuroxime achieved in cerebrospinal fluid during multiple dosing of patients with meningitis.

Table 1. Concentrations of Cefuroxime Achieved in Cerebrospinal Fluid During Multiple Dosing of Patients with Meningitis


Patients Dose Number
of Patients
Mean (Range) CSF Cefuroxime
Concentrations (mcg/mL) Achieved
Within 8 Hours Post Dose
Pediatric patients (4 weeks to 6.5 years) 200 mg/kg/day, divided q 6 hours 5 6.6
(0.9-17.3)
Pediatric patients (7 months to 9 years) 200 to 230 mg/kg/day, divided q 8 hours 6 8.3
(<2-22.5)
Adults 1.5 grams q 8 hours 2 5.2
(2.7-8.9)
Adults 1.5 grams q 6 hours 10 6.0
(1.5-13.5)

Cefuroxime is approximately 50% bound to serum protein.

Microbiology: Cefuroxime has in vitro activity against a wide range of gram-positive and gram-negative organisms, and it is highly stable in the presence of beta-lactamases of certain gram-negative bacteria. The bactericidal action of cefuroxime results from inhibition of cell-wall synthesis.

Cefuroxime is usually active against the following organisms in vitro.

Aerobes, Gram-positive: Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, and Streptococcus pyogenes (and other streptococci). NOTE: Most strains of enterococci, e.g., Enterococcus faecalis (formerly Streptococcus faecalis), are resistant to cefuroxime. Methicillin-resistant staphylococci and Listeria monocytogenes are resistant to cefuroxime.

Aerobes, Gram-negative: Citrobacter spp., Enterobacter spp., Escherichia coli, Haemophilus influenzae (including ampicillin-resistant strains), Haemophilus parainfluenzae, Klebsiella spp. (including Klebsiella pneumoniae), Moraxella (Branhamella) catarrhalis (including ampicillin- and cephalothin-resistant strains), Morganella morganii (formerly Proteus morganii), Neisseria gonorrhoeae (including penicillinase- and non-penicillinase-producing strains), Neisseria meningitidis, Proteus mirabilis, Providencia rettgeri (formerly Proteus rettgeri), Salmonella spp., and Shigella spp.

NOTE: Some strains of Morganella morganii, Enterobacter cloacae, and Citrobacter spp. have been shown by in vitro tests to be resistant to cefuroxime and other cephalosporins. Pseudomonas and Campylobacter spp., Legionella spp., Acinetobacter calcoaceticus, and most strains of Serratia spp. and Proteus vulgaris are resistant to most first- and second-generation cephalosporins.

Anaerobes: Gram-positive and gram-negative cocci (including Peptococcus and Peptostreptococcus spp.), gram-positive bacilli (including Clostridium spp.), and gram-negative bacilli (including Bacteroides and Fusobacterium spp.).

NOTE: Clostridium difficile and most strains of Bacteroides fragilis are resistant to cefuroxime.

Susceptibility Tests: Diffusion Techniques: Quantitative methods that require measurement of zone diameters give an estimate of antibiotic susceptibility. One such standard procedure1 that has been recommended for use with disks to test susceptibility of organisms to cefuroxime uses the 30-mcg cefuroxime disk. Interpretation involves the correlation of the diameters obtained in the disk test with the minimum inhibitory concentration (MIC) for cefuroxime.

A report of "Susceptible" indicates that the pathogen is likely to be inhibited by generally achievable blood levels. A report of "Moderately Susceptible" suggests that the organism would be susceptible if high dosage is used or if the infection is confined to tissues and fluids in which high antibiotic levels are attained. A report of "Intermediate" suggests an equivocable or indeterminate result. A report of "Resistant" indicates that achievable concentrations of the antibiotic are unlikely to be inhibitory and other therapy should be selected.

Reports from the laboratory giving results of the standard single-disk susceptibility test for organisms other than Haemophilus spp. and Neisseria gonorrhoeae with a 30-mcg cefuroxime disk should be interpreted according to the following criteria:


Zone Diameter (mm) Interpretation
≥18 (S) Susceptible
15-17 (MS) Moderately Susceptible
≤14 (R) Resistant

Results for Haemophilus spp. should be interpreted according to the following criteria:


Zone Diameter (mm) Interpretation
≥24 (S) Susceptible
21-23 (I) Intermediate
≤20 (R) Resistant

Results for Neisseria gonorrhoeae should be interpreted according to the following criteria:


Zone Diameter (mm) Interpretation
≥31 (S) Susceptible
26-30 (MS) Moderately Susceptible
≤25 (R) Resistant

Organisms should be tested with the cefuroxime disk since cefuroxime has been shown by in vitro tests to be active against certain strains found resistant when other beta-lactam disks are used. The cefuroxime disk should not be used for testing susceptibility to other cephalosporins.

Standardized procedures require the use of laboratory control organisms. The 30-mcg cefuroxime disk should give the following zone diameters.

1. Testing for organisms other than Haemophilus spp. and Neisseria gonorrhoeae:

 

Organism Zone Diameter (mm)
Staphylococcus aureus ATCC 25923 27-35
Escherichia coli ATCC 25922 20-26

2. Testing for Haemophilus spp.:

 

Organism Zone Diameter (mm)
Haemophilus influenzae ATCC 49766 28-36

3. Testing for Neisseria gonorrhoeae:


Organism Zone Diameter (mm)
Neisseria gonorrhoeae ATCC 49226 33-41
Staphylococcus aureus ATCC 25923 29-33

Dilution Techniques: Use a standardized dilution method1 (broth, agar, microdilution) or equivalent with cefuroxime powder. The MIC values obtained for bacterial isolates other than Haemophilus spp. and Neisseria gonorrhoeae should be interpreted according to the following criteria:


MIC (mcg/mL) Interpretation
≤8 (S) Susceptible
16 (MS) Moderately Susceptible
≥32 (R) Resistant

MIC values obtained for Haemophilus spp. should be interpreted according to the following criteria:


MIC (mcg/mL) Interpretation
≤4 (S) Susceptible
8 (I) Intermediate
≥16 (R) Resistant

MIC values obtained for Neisseria gonorrhoeae should be interpreted according to the following criteria:


MIC (mcg/mL) Interpretation
≤1 (S) Susceptible
2 (MS) Moderately Susceptible
≥4 (R) Resistant

As with standard diffusion techniques, dilution methods require the use of laboratory control organisms. Standard cefuroxime powder should provide the following MIC values.

1. For organisms other than Haemophilus spp. and Neisseria gonorrhoeae:


Organism MIC (mcg/mL)
Staphylococcus aureus ATCC 29213 0.5-2.0
Escherichia coli ATCC 25922 2.0-8.0

2. For Haemophilus spp.:


Organism MIC (mcg/mL)
Haemophilus influenzae ATCC 49766 0.25-1.0

3. For Neisseria gonorrhoeae:


Organism MIC (mcg/mL)
Neisseria gonorrhoeae ATCC 49226 0.25-1.0
Staphylococcus aureus ATCC 29213 0.25-1.0

1. National Committee for Clinical Laboratory Standards. Performance Standards for Antimicrobial Susceptibility Testing. Third Informational Supplement. NCCLS Document M100-S3, Vol. 11, No. 17. Villanova, Pa: NCCLS; 1991.

Last reviewed on RxList: 8/17/2007
This monograph has been modified to include the generic and brand name in many instances.

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