CEFOXITIN- cefoxitin sodium injection, powder, for solution
West-Ward Pharmaceuticals Corp
Rx Only
To reduce the development of drug-resistant bacteria and maintain the effectiveness of cefoxitin for injection and other antibacterial drugs, cefoxitin for injection should be used only to treat or prevent infections that are proven or strongly suspected to be caused by bacteria.
DESCRIPTION
Cefoxitin for injection is a semi-synthetic, broad-spectrum cepha antibiotic sealed under nitrogen for intravenous administration. It is derived from cephamycin C, which is produced by Streptomyces lactamdurans. 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 C16 H16 N3 NaO7 S2 , and the structural formula is:
Chemical structure
(click image for full-size original)
Cefoxitin for injection contains approximately 53.8 mg (2.3 milliequivalents) of sodium per gram of cefoxitin activity. Solutions of cefoxitin for injection range from colorless to light amber in color. The pH of freshly constituted solutions usually ranges from 4.2 to 7.0. Cefoxitin for Injection, USP contains sterile cefoxitin sodium, USP equivalent to 1 or 2 grams cefoxitin.
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 of 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.
