In vitro tests demonstrate that the bactericidal action of cephalosporins results from inhibition of cell wall synthesis. Cefazolin has been shown to be active against most strains of the following microorganisms, both in vitro and in clinical infections as described in INDICATIONS AND USAGE.
Staphylococcus aureus (including ß-lactamase-producing strains)
Streptococcus pyogenes, Streptococcus agalactiae, and other strains of streptococci
Methicillin-resistant staphylococci are uniformly resistant to cefazolin, and many strains of enterococci are resistant.
Most strains of indole positive Proteus (Proteus vulgaris), Enterobacter spp., Morganella morganii, Providencia rettgeri, Serratia spp., and Pseudomonas spp. are resistant to cefazolin.
INDICATIONS AND USAGE:
Cefazolin Injection, USP is indicated in the treatment of the following infections due to susceptible organisms:
Respiratory Tract Infections:
Due to S. pneumoniae, S. aureus (including β-lactamase-producing strains), and S. pyogenes.
Injectable benzathine penicillin is considered to be the drug of choice in treatment and prevention of streptococcal infections, including the prophylaxis of rheumatic fever. Cefazolin is effective in the eradication of streptococci from the nasopharynx; however, data establishing the efficacy of cefazolin in the subsequent prevention of rheumatic fever are not available.
Urinary Tract Infections:
Due to E. coli, P. mirabilis.
Skin and Skin Structure Infections:
Due to S. aureus (including β-lactamase-producing strains), S. pyogenes, and other strains of streptococci.
Biliary Tract Infections:
Due to E. coli, various strains of streptococci, P. mirabilis, and S. aureus.
Bone and Joint Infections:
Due to S. aureus.
(i.e., prostatitis, epididymitis) due to E. coli, P. mirabilis.
Due to S. pneumoniae, S. aureus (including β-lactamase-producing strains) P. mirabilis, E. coli.
Due to S. aureus (including β-lactamase-producing strains), and S. pyogenes.
Appropriate culture and susceptibility studies should be performed to determine susceptibility of the causative organism to cefazolin.
The prophylactic administration of cefazolin preoperatively, intraoperatively, and postoperatively may reduce the incidence of certain postoperative infections in patients undergoing surgical procedures which are classified as contaminated or potentially contaminated (e.g., vaginal hysterectomy, and cholecystectomy in high-risk patients such as those older than 70 years, with acute cholecystitis, obstructive jaundice, or common duct bile stones).
The perioperative use of cefazolin may also be effective in surgical patients in whom infection at the operative site would present a serious risk (e.g., during open-heart surgery and prosthetic arthroplasty).
The prophylactic administration of cefazolin should usually be discontinued within a 24-hour period after the surgical procedure. In surgery where the occurrence of infection may be particularly devastating (e.g., open-heart surgery and prosthetic arthroplasty), the prophylactic administration of cefazolin may be continued for 3 to 5 days following the completion of surgery.
If there are signs of infection, specimens for cultures should be obtained for the identification of the causative organism so that appropriate therapy may be instituted.
To reduce the development of drug-resistant bacteria and maintain the effectiveness of cefazolin and other antibacterial drugs, cefazolin 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 are 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:
Usual Adult Dosage:
|Type of Infection
|Moderate to severe infections
|500 mg to 1 gram
|every 6 to 8 hrs.
|Mild infections caused by susceptible gram-positive cocci
|250 mg to 500 mg
|every 8 hours
|Acute, uncomplicated urinary tract
|every 12 hours
|every 12 hours
|Severe, life-threatening infections (e.g.,
|1 gram to 1.5 grams
|every 6 hours
*In rare instances, doses of up to 12 grams of Cefazolin Injection per day have been used.
Perioperative Prophylactic Use
To prevent postoperative infection in contaminated or potentially contaminated surgery, recommended doses are:
1. 1 gram IV administered one-half hour to 1 hour prior to start of surgery.
2. For lengthy operative procedures (e.g., 2 hours or more), 500 mg to 1 gram IV during surgery (administration modified depending on the duration of the operative procedure).
3. 500 mg to 1 gram IV every 6 to 8 hours for 24 hours postoperatively.
It is important that (1) the preoperative dose be given just (1/2 to 1 hour) prior to start of surgery so that adequate antibiotic levels are present in the serum and tissues at the time of initial surgical incision; and (2) cefazolin be administered, if necessary, at appropriate intervals during surgery to provide sufficient levels of the antibiotic at the anticipated moments of greatest exposure to infective organisms.
In surgery where the occurrence of infection may be particularly devastating (e.g., open-heart surgery and prosthetic arthroplasty), the prophylactic administration of cefazolin may be continued for 3 to 5 days following the completion of surgery.
Renal Dosing: ------------------------
Cefazolin Injection may be used in patients with reduced renal function with the following dosage adjustments: Patients with a creatinine clearance of 55 mL/min. or greater or a serum creatinine of 1.5 mg % or less can be given full doses. Patients with creatinine clearance rates of 35 to 54 mL/min. or serum creatinine of 1.6 to 3.0 mg % can also be given full doses but dosage should be restricted to at least 8 hour intervals.
Patients with creatinine clearance rates of 11 to 34 mL/min. or serum creatinine of 3.1 to 4.5 mg % should be given one-half the usual dose every 12 hours.
Patients with creatinine clearance rates of 10 mL/min. or less or serum creatinine of 4.6 mg % or greater should be given ½ the usual dose every 18 to 24 hours.
All reduced dosage recommendations apply after an initial loading dose appropriate to the severity of the infection.
Package insert data: