Microbiology:
The bactericidal action of cefoxitin results from inhibition of cell wall synthesis. Cefoxitin has in vitro activity against a wide range of gram-positive and gram-negative organisms. The methoxy group in the 7a position provides cefoxitin with a high degree of stability in the presence of beta-lactamases, both penicillinases and cephalosporinases, of gram-negative bacteria.
Cefoxitin 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.
Aerobic gram-positive microorganisms
Staphylococcus aureus (including penicillinase-producing strains)
Staphylococcus epidermidis
Streptococcus agalactiae
Streptococcus pneumoniae
Streptococcus pyogenes
Staphylococci resistant to methicillin/oxacillin should be considered resistant to cefoxitin.
Most strains of enterococci, e.g., Enterococcus faecalis, are resistant.
Aerobic gram-negative microorganisms
Escherichia coli
Haemophilus influenzae
Klebsiella spp. (including K. pneumoniae)
Morganella morganii
Neisseria gonorrhoeae (including penicillinase-producing strains)
Proteus mirabilis
Proteus vulgaris
Providencia spp. (including Providencia rettgeri)
Anaerobic gram-positive microorganisms
Clostridium spp.
Peptococcus niger
Peptostreptococcus spp.
Anaerobic gram-negative microorganisms
Bacteroides distasonis
Bacteroides fragilis
Bacteroides ovatus
Bacteroides thetaiotaomicron
Bacteroides spp.
The following in vitro data are available, but their clinical significance is unknown.
Cefoxitin exhibits in vitro minimum inhibitory concentrations (MIC's) of 8 mcg/mL or less for aerobic microorganisms and 16 mcg/mL or less for anaerobic microorganisms against most (>/= 90%) strains of the following microorganisms; however, the safety and effectiveness of cefoxitin in treating clinical infections due to these microorganisms have not been established in adequate and well-controlled clinical trials.
Aerobic gram-negative microorganisms
Eikenella corrodens (non-β-lactamase producers)
Klebsiella oxytoca
Anaerobic gram-positive microorganisms
Clostridium perfringens
Anaerobic gram-negative microorganisms
Prevotella bivia (formerly Bacteroides bivius)
Cefoxitin is inactive in vitro against most strains of Pseudomonas aeruginosa and enterococci and many strains of Enterobacter cloacae.
INDICATIONS AND USAGE:
Treatment
Cefoxitin for Injection, USP is indicated for the treatment of serious infections caused by susceptible strains of the designated microorganisms in the diseases listed below.
(1) Lower respiratory tract infections, including pneumonia and lung abscess, caused by Streptococcus pneumoniae, other streptococci (excluding enterococci, e.g., Enterococcus faecalis [formerly Streptococcus faecalis]), Staphylococcus aureus (including penicillinase-producing strains), Escherichia coli, Klebsiella species, Haemophilus influenzae, and Bacteroides species.
(2) Urinary tract infections caused by Escherichia coli, Klebsiella species, Proteus mirabilis, Morganella morganii, Proteus vulgaris and Providencia species (including P. rettgeri).
(3) Intra-abdominal infections, including peritonitis and intra-abdominal abscess, caused by Escherichia coli, Klebsiella species, Bacteroides species including Bacteroides fragilis, and Clostridium species.
(4) Gynecological infections, including endometritis, pelvic cellulitis, and pelvic inflammatory disease caused by Escherichia coli, Neisseria gonorrhoeae (including penicillinase-producing strains), Bacteroides species including B. fragilis, Clostridium species, Peptococcus niger, Peptostreptococcus species, and Streptococcus agalactiae. Cefoxitin for Injection, USP, like cephalosporins, has no activity against Chlamydia trachomatis. Therefore, when Cefoxitin for Injection, USP is used in the treatment of patients with pelvic inflammatory disease and C. trachomatis is one of the suspected pathogens, appropriate anti-chlamydial coverage should be added.
(5) Septicemia caused by Streptococcus pneumoniae, Staphylococcus aureus (including penicillinase-producing strains), Escherichia coli, Klebsiella species, and Bacteroides species including B. fragilis.
(6) Bone and joint infections caused by Staphylococcus aureus (including penicillinase-producing strains).
(7) Skin and skin structure infections caused by Staphylococcus aureus (including penicillinase-producing strains), Staphylococcus epidermidis, Streptococcus pyogenes and other streptococci (excluding enterococci e.g., Enterococcus faecalis [formerly Streptococcus faecalis]), Escherichia coli, Proteus mirabilis, Klebsiella species, Bacteroides species including B. fragilis, Clostridium species, Peptococcus niger, and Peptostreptococcus species.
Appropriate culture and susceptibility studies should be performed to determine the susceptibility of the causative organisms to Cefoxitin for Injection, USP. Therapy may be started while awaiting the results of these studies.
In randomized comparative studies, Cefoxitin for Injection, USP and cephalothin were comparably safe and effective in the management of infections caused by gram-positive cocci and gram-negative rods susceptible to the cephalosporins. Cefoxitin for Injection, USP has a high degree of stability in the presence of bacterial beta-lactamases, both penicillinases and cephalosporinases.
Many infections caused by aerobic and anaerobic gram-negative bacteria resistant to some cephalosporins respond to Cefoxitin for Injection, USP. Similarly, many infections caused by aerobic and anaerobic bacteria resistant to some penicillin antibiotics (ampicillin, carbenicillin, penicillin G) respond to treatment with Cefoxitin for Injection, USP. Many infections caused by mixtures of susceptible aerobic and anaerobic bacteria respond to treatment with Cefoxitin for Injection, USP.
Prevention
Cefoxitin for Injection, USP is indicated for the prophylaxis of infection in patients undergoing uncontaminated gastrointestinal surgery, vaginal hysterectomy, abdominal hysterectomy, or cesarean section.
If there are signs of infection, specimens for culture should be obtained for identification of the causative organism so that appropriate treatment may be instituted.
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 susceptible bacteria. When culture and susceptibility information is available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.
DOSAGE AND ADMINISTRATION:
TREATMENT
Adults
The usual adult dosage range is 1 gram to 2 grams every six to eight hours. Dosage should be determined by susceptibility of the causative organisms, severity of infection, and the condition of the patient (see Table 1 for dosage guidelines).
If C. trachomatis is a suspected pathogen, appropriate anti-chlamydial coverage should be added, because cefoxitin sodium has no activity against this organism.
MEFOXIN may be used in patients with reduced renal function with the following dosage adjustments:
In adults with renal insufficiency, an initial loading dose of 1 gram to 2 grams may be given. After a loading dose, the recommendations for maintenance dosage (Table 2) may be used as a guide.
When only the serum creatinine level is available, the following formula (based on sex, weight, and age of the patient) may be used to convert this value into creatinine clearance. The serum creatinine should represent a steady state of renal function.
Males = Weight (kg) x (140-age) / [72 x serum creatinine (mg/100 mL)]
Females = 0.85 x male value
In patients undergoing hemodialysis, the loading dose of 1 to 2 grams should be given after each hemodialysis, and the maintenance dose should be given as indicated in Table 2.
Antibiotic therapy for group A beta-hemolytic streptococcal infections should be maintained for at least 10 days to guard against the risk of rheumatic fever or glomerulonephritis. In staphylococcal and other infections involving a collection of pus, surgical drainage should be carried out where indicated.
Pediatric Patients
The recommended dosage in pediatric patients three months of age and older is 80 to 160 mg/kg of body weight per day divided into four to six equal doses. The higher dosages should be used for more severe or serious infections. The total daily dosage should not exceed 12 grams.
At this time no recommendation is made for pediatric patients from birth to three months of age.
In pediatric patients with renal insufficiency, the dosage and frequency of dosage should be modified consistent with the recommendations for adults (see Table 2).
PREVENTION
Effective prophylactic use depends on the time of administration. MEFOXIN usually should be given one-half to one hour before the operation, which is sufficient time to achieve effective levels in the wound during the procedure. Prophylactic administration should usually be stopped within 24 hours since continuing administration of any antibiotic increases the possibility of adverse reactions but, in the majority of surgical procedures, does not reduce the incidence of subsequent infection.
For prophylactic use in uncontaminated gastrointestinal surgery, vaginal hysterectomy, or abdominal hysterectomy, the following doses are recommended:
Adults:
2 grams administered intravenously just prior to surgery (approximately one-half to one hour before the initial incision) followed by 2 grams every 6 hours after the first dose for no more than 24 hours.
Pediatric Patients (3 months and older):
30 to 40 mg/kg doses may be given at the times designated above.
Cesarean section patients:
For patients undergoing cesarean section, either a single 2 gram dose administered intravenously as soon as the umbilical cord is clamped OR a 3-dose regimen consisting of 2 grams given intravenously as soon as the umbilical cord is clamped followed by 2 grams 4 and 8 hours after the initial dose is recommended.
Table 1: Guidelines for Dosage of MEFOXIN
Type of Infection |
Daily Dosage |
Frequency and Route |
*Including patients in whom bacteremia is absent or unlikely. |
Uncomplicated forms* of infections such as pneumonia, urinary tract infection, cutaneous infection |
3-4 grams |
1 gram every 6-8 hours IV |
Moderately severe or severe infections |
6-8 grams |
1 gram every 4 hours
or
2 grams every 6-8 hours IV |
Infections commonly needing antibiotics in higher dosage (e.g., gas gangrene) |
12 grams |
2 grams every 4 hours
or
3 grams every 6 hours IV |
Renal Dosing: -----------------------------
Table 2: Maintenance Dosage of MEFOXIN in Adults with Reduced Renal Function
Renal Function
|
Creatinine Clearance
(mL/min) |
Dose
(grams) |
Frequency
|
Mild impairment |
50-30 |
1-2 |
every 8-12 hours |
Moderate impairment |
29-10 |
1-2 |
every 12-24 hours |
Severe impairment |
9-5 |
0.5-1 |
every 12-24 hours |
Essentially no function |
<5 |
0.5-1 |
every 24-48 hours |
Table 3: Preparation of Solution for Intravenous Administration
Strength |
Amount of Diluent to be Added (mL)* |
Approximate Withdrawable Volume (mL) |
Approximate Average Concentration (mg/mL) |
*Shake to dissolve and let stand until clear. |
1 gram Vial |
10 |
10.5 |
95 |
2 gram Vial |
10 or 20 |
11.1 or 21.0 |
180 or 95 |
1 gram Infusion Bottle |
50 or 100 |
50 or 100 |
20 or 10 |
2 gram Infusion Bottle |
50 or 100 |
50 or 100 |
40 or 20 |
10 gram Bulk |
43 or 93 |
49 or 98.5 |
200 or 100 |
SOURCE:
Package insert data: