Microbiology

Mechanism of Action

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

Resistance

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

Antimicrobial Activity

Cefotetan has been shown to be active against most isolates of the following microorganisms both in vitro and in clinical infections (see INDICATIONS AND USAGE).

Gram-Negative Bacteria

Escherichia coli

Haemophilus influenza

Klebsiella species

(including K. pneumoniae)

Morganella morganii

Neisseria gonorrhoeae

Proteus mirabilis

Proteus vulgaris

Providencia rettgeri

Serratia marcescens

Gram-Positive Bacteria

Staphylococcus aureus (methicillin-susceptible isolates only)

Staphylococcus epidermidis (methicillin-susceptible isolates only)

Streptococcus agalactiae

Streptococcus pneumoniae

Streptococcus pyogenes

Streptococcus species

Anaerobes

Prevotella bivia

Prevotella disiens

Bacteroides fragilis

Prevotella melaninogenica

Bacteroides vulgatus

Fusobacterium species

Clostridium species

Peptococcus niger

Peptostreptococcus species

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

Gram-Negative Bacteria

Citrobacter species (including C. koseri and C. freundii )

Moraxella catarrhalis

Salmonella species

Serratia species

Shigella species

Yersinia enterocolitica

 Anaerobes

Porphyromonas asaccharolytica

Prevotella oralis

Bacteroides splanchnicus

Propionibacterium species

Veillonella species

Susceptibility Testing

For specific information regarding susceptibility test interpretive criteria and associated test methods and quality control standards recognized by FDA for this drug, please see: https://www.fda.gov/STIC.

Treatment

Cefotetan for Injection, USP is indicated for the therapeutic treatment of the following infections when caused by susceptible strains of the designated organisms:

Urinary Tract Infections caused by E. coli, Klebsiella spp (including K. pneumoniae), Proteus mirabilis, Proteusvulgaris, Providencia rettgeri, and Morganella morganii).

Lower Respiratory Tract Infections caused by Streptococcus pneumoniae, Staphylococcus aureus (methicillin-susceptible), Haemophilus influenzae, Klebsiella species (including K. pneumoniae), E. coli, Proteus mirabilis, and Serratia marcescens.*

Skin and Skin Structure Infections due to Staphylococcus aureus (methicillin-susceptible), Staphylococcus epidermidis (methicillin susceptible), Streptococcus pyogenes, Streptococcus species, Escherichia coli, Klebsiella pneumoniae, Peptococcus niger*, Peptostreptococcus species.

Gynecologic Infections caused by Staphylococcus aureus (methicillin susceptible), Staphylococcus epidermidis (methicillin susceptible), Streptococcus species, Streptococcus agalactiae, E. coli, Proteus mirabilis, Neisseria gonorrhoeae, Bacteroidesfragilis, Prevotella melaninogenica, Bacteroides vulgatus, Fusobacterium species*, and gram-positive anaerobic cocci (including Peptococcus niger and Peptostreptococcus species).

Cefotetan, like other cephalosporins, has no activity against Chlamydia trachomatis.  Therefore, when cephalosporins are used in the treatment of pelvic inflammatory disease, and C. trachomatis is one of the suspected pathogens, appropriate antichlamydial coverage should be added.

Intra-abdominal lnfections caused by E. coli, Klebsiella species (including K. pneumoniae), Streptococcus species, Bacteroidesfragilis, Prevotella melaninogenica, Bacteroidesvulgatus and Clostridium species (other than Clostridium difficile[see WARNINGS])*.

Bone and Joint Infections caused by Staphylococcus aureus (methicillin susceptible)*.

* Efficacy for this organism in this organ system was studied in fewer than ten infections in clinical studies

Specimens for bacteriological examination should be obtained in order to isolate and identify causative organisms and to determine their susceptibilities to cefotetan.  Therapy may be instituted before results of susceptibility studies are known; however, once these results become available, the antibiotic treatment should be adjusted accordingly.

In cases of confirmed or suspected gram-positive or gram-negative sepsis or in patients with other serious infections in which the causative organism has not been identified, it is possible to use cefotetan concomitantly with an aminoglycoside.  Cefotetan combinations with aminoglycosides have been shown to be synergistic in vitro against many Enterobacteriaceae and also some other gram-negative bacteria.  The dosage recommended in the labeling of both antibiotics may be given and depends on the severity of the infection and the patient's condition.

NOTE: Increases in serum creatinine have occurred when cefotetan was given alone.  If cefotetan and an aminoglycoside are used concomitantly, renal function should be carefully monitored, because nephrotoxicity may be potentiated.

Prophylaxis

The preoperative administration of cefotetan may reduce the incidence of certain postoperative infections in patients undergoing surgical procedures that are classified as clean contaminated or potentially contaminated (e.g., cesarean section, abdominal or vaginal hysterectomy, transurethral surgery, biliary tract surgery, and gastrointestinal surgery).

If there are signs and symptoms of infection, specimens for culture should be obtained for identification of the causative organism so that appropriate therapeutic measures may be initiated.

General

Prescribing cefotetan in the absence of proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria.

As with other broad-spectrum antibiotics, prolonged use of cefotetan may result in overgrowth of nonsusceptible organisms.  Careful observation of the patient is essential.  If superinfection does occur during therapy, appropriate measures should be taken.

Cefotetan should be used with caution in individuals with a history of gastrointestinal disease, particularly colitis.

Information for Patients

Diarrhea is a common problem caused by antibiotics which usually ends when the antibiotic is discontinued.  Sometimes after starting treatment with antibiotics, patients can develop watery and bloody stools (with or without stomach cramps and fever) even as late as two or more months after having taken the last dose of the antibiotic.  If this occurs, patients should contact their physician as soon as possible.

Patients should be counseled that antibacterial drugs, including cefotetan, should only be used to treat bacterial infections.  They do not treat viral infections (e.g., the common cold).  When cefotetan is prescribed to treat a bacterial infection, patients should be told that although it is common to feel better early in the course of therapy, the medication should be taken exactly as directed.  Skipping doses or not completing the full course of therapy may (1) decrease the effectiveness of the immediate treatment and (2) increase the likelihood that bacteria will develop resistance and will not be treatable by Cefotetan for Injection, USP or other antibacterial drugs in the future.

As with some other cephalosporins, a disulfiram-like reaction characterized by flushing, sweating, headache, and tachycardia may occur when alcohol (beer, wine, etc.) is ingested within 72 hours after Cefotetan for Injection, USP administration.  Patients should be cautioned about the ingestion of alcoholic beverages following the administration of cefotetan.

Drug Interactions

Increases in serum creatinine have occurred when cefotetan was given alone.  If cefotetan and an aminoglycoside are used concomitantly, renal function should be carefully monitored, because nephrotoxicity may be potentiated.

Drug/Laboratory Test Interactions

The administration of cefotetan may result in a false positive reaction for glucose in the urine using Clinitest

®‡, Benedict's solution, or Fehling's solution.  It is recommended that glucose tests based on enzymatic glucose oxidase be used. 

As with other cephalosporins, high concentrations of cefotetan may interfere with measurement of serum and urine creatinine levels by Jaffé reaction and produce false increases in the levels of creatinine reported.

Carcinogenesis, Mutagenesis, Impairment of Fertility

Although long-term studies in animals have not been performed to evaluate carcinogenic potential, no mutagenic potential of cefotetan was found in standard laboratory tests.

Cefotetan has adverse affects on the testes of prepubertal rats.  Subcutaneous administration of 500 mg/kg/day (approximately 0.8 times the maximum adult human dose on a body surface area basis) on days 6 to 35 of life (thought to be developmentally analogous to late childhood and prepuberty in humans) resulted in reduced testicular weight and seminiferous tubule degeneration in 10 of 10 animals.  Affected cells included spermatogonia and spermatocytes; Sertoli and Leydig cells were unaffected.  Incidence and severity of lesions were dose-dependant; at 120 mg/kg/day (0.2 times the maximum human dose on a body surface area basis) only 1 of 10 treated animals was affected, and the degree of degeneration was mild.

Similar lesions have been observed in experiments of comparable design with other methylthiotetrazole-containing antibiotics and impaired fertility has been reported, particularly at high dose levels.  No testicular effects were observed in 7-week-old rats treated with up to 1000 mg/kg/day SC for 5 weeks, or in infant dogs (3 weeks old) that received up to 300 mg/kg/day IV for 5 weeks (both 1.6 times the maximum recommended human dose on a body surface area basis).  The relevance of these findings to humans is unknown.

Pregnancy

Teratogenic Effects. Pregnancy Category B

There are, however, no adequate and well-controlled studies in pregnant women.  Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.

Reproduction studies have been performed in rats and monkeys at doses of up to 2000 and 600 mg/kg/day, or 3 and 2 times the maximum recommended human dose on a body surface area basis, and have revealed no evidence of impaired fertility or harm to the fetus due to cefotetan.

Nursing Mothers

Cefotetan is excreted in human milk in very low concentrations.  Caution should be exercised when cefotetan is administered to a nursing woman.

Pediatric Use

Safety and effectiveness in pediatric patients have not been established.

Geriatric Use

Of the 925 subjects who received cefotetan in clinical studies, 492 (53%) were 60 years and older, while 76 (8%) were 80 years and older.  No overall differences in safety or effectiveness were observed between these subjects and younger subjects, and the other reported clinical experience has not identified differences in responses between elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out.

This drug is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function.  Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function (see DOSAGE AND ADMINISTRATION,  Impaired Renal Function).

Treatment

The usual adult dosage is 1 gram (g) or 2 grams of Cefotetan for Injection, USP administered intravenously or intramuscularly.  Proper dosage and route of administration should be determined by the condition of the patient, severity of the infection, and susceptibility of the causative organism.

If Chlamydia trachomatis is a suspected pathogen in gynecologic infections, appropriate antichlamydial coverage should be added, since cefotetan has no activity against this organism.

Prophylaxis

To prevent postoperative infection in clean contaminated or potentially contaminated surgery in adults, the recommended dosage is 1 or 2 g of Cefotetan for Injection, USP administered once, intravenously, 30 to 60 minutes prior to surgery.  In patients undergoing cesarean section, the dose should be administered as soon as the umbilical cord is clamped.

Impaired Renal Function

When renal function is impaired, a reduced dosage schedule must be employed.  The following dosage guidelines may be used.

* Dose determined by the type and severity of infection, and susceptibility of the causative organism.

Alternatively, the dosing interval may remain constant at 12 hour intervals, but the dose reduced to one-half the usual recommended dose for patients with a creatinine clearance of 10 to 30 mL/min, and one-quarter the usual recommended dose for patients with a creatinine clearance of less than 10 mL/min.

When only serum creatinine levels are available, creatinine clearance may be calculated from the following formula.  The serum creatinine level 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 value for males

Cefotetan is dialyzable and it is recommended that for patients undergoing intermittent hemodialysis, one-quarter of the usual recommended dose be given every 24 hours on days between dialysis and one-half the usual recommended dose on the day of dialysis.

Preparation of Solution

For Intravenous Use

Reconstitute with Sterile Water for Injection.  Shake to dissolve and let stand until clear.

For Intramuscular Use

Reconstitute with Sterile Water for Injection; Bacteriostatic Water for Injection; Sodium Chloride Injection 0.9%, USP; 0.5% Lidocaine HCl; or 1% Lidocaine HCl.  Shake to dissolve and let stand until clear.

Intravenous Administration

The intravenous route is preferable for patients with bacteremia, bacterial septicemia, or other severe or life-threatening infections, or for patients who may be poor risks because of lowered resistance resulting from such debilitating conditions as malnutrition, trauma, surgery, diabetes, heart failure, or malignancy, particularly if shock is present or impending.

For intermittent intravenous administration, a solution containing 1 gram or 2 grams of Cefotetan for Injection, USP in Sterile Water for Injection can be injected over a period of three to five minutes.  Using an infusion system, the solution may also be given over a longer period of time through the tubing system by which the patient may be receiving other intravenous solutions.  Butterfly® or scalp vein-type needles are preferred for this type of infusion.  However, during infusion of the solution containing Cefotetan for Injection, USP, it is advisable to discontinue temporarily the administration of other solutions at the same site.

NOTE: Solutions of cefotetan must not be admixed with solutions containing aminoglycosides.  If cefotetan and aminoglycosides are to be administered to the same patient, they must be administered separately and not as a mixed injection.

Intramuscular Administration

As with all intramuscular preparations, Cefotetan for Injection, USP should be injected well within the body of a relatively large muscle such as the upper outer quadrant of the buttock (i.e., gluteus maximus); aspiration is necessary to avoid inadvertent injection into a blood vessel.

Compatibility and Stability

Frozen samples should be thawed at room temperature before use.  After the periods mentioned below, any unused solutions or frozen material should be discarded.  DO NOT REFREEZE.

NOTE: Solutions of Cefotetan for Injection, USP must not be admixed with solutions containing aminoglycosides.  If Cefotetan for Injection, USP and aminoglycosides are to be administered to the same patient, they must be administered separately and not as a mixed injection.  DO NOT ADD SUPPLEMENTARY MEDICATION.

Cefotetan for Injection, USP reconstituted as described above (see DOSAGE AND ADMINISTRATION, Preparation of Solution) maintains satisfactory potency for 24 hours at room temperature (25°C/77°F), for 96 hours under refrigeration (5°C/41°F), and for at least 1 week in the frozen state (-20°C/-4°F).  After reconstitution and subsequent storage in disposable glass or plastic syringes, Cefotetan for Injection, USP is stable for 24 hours at room temperature and 96 hours under refrigeration.

NOTE: Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration whenever solution and container permit.