Cefoxitin for Injection, USP - America[美国药品]

TOP

Cefoxitin for Injection, USP

2016-09-26 06:33:55 来源: 作者: 【大中小】浏览:369次评论:0条

SPL UNCLASSIFIED SECTION

SAGENT™

Rx only
RECONSTITUTED BULK SOLUTION SHOULD NOT BE USED FOR DIRECT INFUSION.

To reduce the development of drug-resistant bacteria and maintain the effectiveness of Cefoxitin for Injection, USP and other antibacterial drugs, Cefoxitin for Injection, USP should be used only to treat or prevent infections that are proven or strongly suspected to be caused by bacteria.

DESCRIPTION

Cefoxitin for Injection, USP contains cefoxitin sodium a semi-synthetic, broad-spectrum cephalosporin antibiotic for parenteral administration. It is derived from cephalosporin C, which is produced by Cephalosporium Acremonium. Its chemical name is sodium (6R, 7S)-3-(hydroxymethyl)-7-methoxy-8-oxo-7-[2-(2-thienyl)acetamido]-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate carbamate (ester). The molecular formula is C16H16N3NaO7S2, and the structural formula is:

Cefoxitin for Injection, USP is supplied as a dry powder in vials and contains approximately 53.8 mg (2.3 milliequivalents) of sodium per gram of cefoxitin activity. Solutions of Cefoxitin for Injection, USP range from colorless to light amber in color. The pH of freshly constituted solutions usually ranges from 4.2 to 7.

Each pharmacy bulk package bottle contains sterile cefoxitin sodium, USP equivalent to 10 g of cefoxitin and is intended for intravenous infusion only. A pharmacy bulk package is a container of a sterile preparation for parenteral use that contains many single doses. The contents are intended for use in a pharmacy admixture service and are restricted to the preparation of admixtures for intravenous infusion. FURTHER DILUTION IS REQUIRED BEFORE USE. RECONSTITUTED BULK SOLUTION SHOULD NOT BE USED FOR DIRECT INFUSION. RECONSTITUTED STOCK SOLUTION MUST BE TRANSFERRED AND FURTHER DILUTED FOR I.V. INFUSION.

CLINICAL PHARMACOLOGY

Clinical Pharmacology

Following an intravenous dose of 1 gram, serum concentrations were 110 mcg/mL at 5 minutes, declining to less than 1 mcg/mL at 4 hours. The half-life after an intravenous dose is 41 to 59 minutes. Approximately 85 percent of cefoxitin is excreted unchanged by the kidneys over a 6-hour period, resulting in high urinary concentrations. Probenecid slows tubular excretion and produces higher serum levels and increases the duration of measurable serum concentrations.

Cefoxitin passes into pleural and joint fluids and is detectable in antibacterial concentrations in bile.

In a published study of geriatric patients ranging in age from 64 to 88 years with normal renal function for their age (creatinine clearance ranging from 31.5 to 174 mL/min), the half-life for cefoxitin ranged from 51 to 90 minutes, resulting in higher plasma concentrations than in younger adults. These changes were attributed to decreased renal function associated with the aging process.

Microbiology

Mechanism of Action

Cefoxitin is a bactericidal agent that acts by inhibition of bacterial cell wall synthesis. Cefoxitin has activity in the presence of some beta-lactamases, both penicillinases and cephalosporinases, of Gram-negative and Gram-positive bacteria.

Mechanism of Resistance

Resistance to cefoxitin is primarily through hydrolysis by beta-lactamase, alteration of penicillin-binding proteins (PBPs), and decreased permeability.

Cefoxitin has been shown to be active against most isolates of the following bacteria, both in vitro and in clinical infections as described in the INDICATIONS AND USAGE section:

Gram-positive bacteria

: Staphylococcus aureus (methicillin-susceptible isolates only)
: Staphylococcus epidermidis (methicillin-susceptible isolates only)
: Streptococcus agalactiae
: Streptococcus pneumoniae
: Streptococcus pyogenes

Gram-negative bacteria

: Escherichia coli
: Haemophilus influenzae
: Klebsiella spp.
: Morganella morganii
: Neisseria gonorrhoeae
: Proteus mirabilis
: Proteus vulgaris
: Providencia spp.

Anaerobic bacteria

: Clostridium spp.
: Peptococcus niger
: Peptostreptococcus spp.
: Bacteroides spp.

The following in vitro data are available, but their clinical significance is unknown. At least 90 percent of the following microorganisms exhibit an in vitro minimum inhibitory concentration (MIC) less than or equal to the susceptible breakpoint for cefoxitin. However, the efficacy of cefoxitin in treating clinical infections due to these microorganisms has not been established in adequate and well-controlled clinical trials.

Gram-negative bacteria

: Eikenella corrodens (non-β-lactamase producers)

Anaerobic bacteria

: Clostridium perfringens
: Prevotella bivia

Susceptibility Test Methods

When available, the clinical microbiology laboratory should provide the results of in vitro susceptibility test results for antimicrobial drug products used in resident hospitals to the physician as periodic reports that describe the susceptibility profile of nosocomial and community-acquired pathogens. These reports should aid the physician in selecting an antibacterial drug product for treatment.

Dilution Techniques

Quantitative methods are used to determine antimicrobial minimal inhibitory concentrations (MICs). These MICs provide estimates of the susceptibility of bacteria to antimicrobial compounds. The MICs should be determined using a standardized test method1,3. The MIC values should be interpreted according to the criteria provided in Table 1.

Diffusion Techniques

Quantitative methods that require measurement of zone diameters also provide reproducible estimates of the susceptibility of bacteria to antimicrobial compounds. The zone size provides an estimate of the susceptibility of bacteria to antimicrobial compounds. The zone size should be determined using a standardized test method2,3. This procedure uses paper disks impregnated with 30 mcg cefoxitin to test the susceptibility of microorganisms to cefoxitin. The disk diffusion interpretive criteria are provided in Table 1.

Table 1 - Susceptibility Test Interpretive Criteria for Cefoxitin2,4
a The clinical effectiveness of cefoxitin for treating organisms that produce intermediate results is unknown2.
b Values derived using either Brucella blood or Wilkins Chalgren agar are considered equivalent. Values for agar and broth microdilution are considered equivalent4.
	Minimum Inhibitory Concentrations (mcg/mL)			Disc Diffusion Diameters (mm)
Pathogen	S	I	R	S	I	R
Enterobacteriaceae	≤ 8	16	≥ 32	≥ 18	15 to 17	≤ 14
Neisseria gonorrhoeaea	≤ 2	4	≥ 8	≥ 28	24 to 27	≤ 23
anaerobic bacteriab	≤ 16	32	≥ 64		Not applicable

A report of Susceptible indicates that the antimicrobial is likely to inhibit growth of the pathogen if the antimicrobial compound reaches the concentration at the infection site necessary to inhibit growth of the pathogen. 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 antimicrobial is not likely to inhibit growth of the pathogen if the antimicrobial compound reaches the concentrations usually achievable at the infection site; other therapy should be selected.

Quality Control

Standardized susceptibility test procedures require the use of laboratory controls to monitor and ensure the accuracy and precision of the supplies and reagents used in the assay, and the techniques of the individual performing the test1,2,3,4. Standard Cefoxitin powder should provide the following range of MIC values noted in Table 2. For the diffusion techniq