a-hemolytic streptococci, and other strains of streptococci. biliary tract infections: due to e. coli, various strains of streptococci, p. mirabilis, klebsiella species, and s. aureus. bone and joint infections: due to s. aureus. genital infections: (i.e., prostatitis, epididymitis) due to e. coli, p. mirabilis, klebsiella species, and some strains of enterococci . septicemia: due to s. pneumoniae, s. aureus (penicillin-sensitive and penicillin-resistant), p. mirabilis, e. coli, and klebsiella species. endocarditis: due to s. aureus (penicillin-sensitive and penicillin-resistant) and group a beta-hemolytic streptococci . perioperative prophylaxis: the prophylactic administration of cefazolin for injection, usp 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 for injection, usp 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 for injection, usp 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 for injection, usp 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. (see dosage and administration .) to reduce the development of drug-resistant bacteria and maintain the effectiveness of cefazolin for injection, usp and other antibacterial drugs, cefazolin 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 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.

e, it is important to consider this diagnosis in patients who present with diarrhea subsequent to the administration of antibacterial agents. treatment with antibacterial agents alters the normal flora of the colon and may permit overgrowth of clostridia. studies indicate that a toxin produced by clostridium difficile is a primary cause of "antibiotic-associated colitis." after the diagnosis of pseudomembranous colitis has been established, therapeutic measures should be initiated. mild cases of pseudomembranous colitis usually respond to drug discontinuation alone. in moderate to severe cases, consideration should be given to management with fluids and electrolytes, protein supplementation, and treatment with an oral antibacterial drug clinically effective against c.difficile colitis.

hours for 24 hours postoperatively. it is important that (1) the preoperative dose be given just ( 1 / 2 to 1 hour) prior to the 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 for injection, usp 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 for injection, usp may be continued for 3 to 5 days following the completion of surgery. dosage adjustment for patients with reduced renal function: cefazolin for injection, usp 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 1 / 2 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 1 / 2 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. patients undergoing peritoneal dialysis: see clinical pharmacology . pediatric dosage: in pediatric patients, a total daily dosage of 25 to 50 mg per kg (approximately 10 to 20 mg per pound) of body weight, divided into 3 or 4 equal doses, is effective for most mild to moderately severe infections. total daily dosage may be increased to 100 mg per kg (45 mg per pound) of body weight for severe infections. since safety for use in premature infants and in neonates has not been established, the use of cefazolin for injection, usp in these patients is not recommended. pediatric dosage guide weight 25 mg/kg/day divided into 3 doses 25 mg/kg/day divided into 4 doses lbs kg approximate single dose mg/q8h vol. (ml) needed with dilution of 125 mg/ml approximate single dose mg/q6h vol. (ml) needed with dilution of 125 mg/ml 10 4.5 40 mg 0.35 ml 30 mg 0.25 ml 20 9.0 75 mg 0.60 ml 55 mg 0.45 ml 30 13.6 115 mg 0.90 ml 85 mg 0.70 ml 40 18.1 150 mg 1.20 ml 115 mg 0.90 ml 50 22.7 190 mg 1.50 ml 140 mg 1.10 ml weight 50 mg/kg/day divided into 3 doses 50 mg/kg/day divided into 4 doses lbs kg approximate single dose mg/q8h vol. (ml) needed with dilution of 225 mg/ml approximate single dose mg/q6h vol. (ml) needed with dilution of 225 mg/ml 10 4.5 75 mg 0.35 ml 55 mg 0.25 ml 20 9.0 150 mg 0.70 ml 110 mg 0.50 ml 30 13.6 225 mg 1.00 ml 170 mg 0.75 ml 40 18.1 300 mg 1.35 ml 225 mg 1.00 ml 50 22.7 375 mg 1.70 ml 285 mg 1.25 ml in pediatric patients with mild to moderate renal impairment (creatinine clearance of 70 to 40 ml/min.), 60 percent of the normal daily dose given in equally divided doses every 12 hours should be sufficient. in patients with moderate impairment (creatinine clearance of 40 to 20 ml/min.), 25 percent of the normal daily dose given in equally divided doses every 12 hours should be adequate. pediatric patients with severe renal impairment (creatinine clearance of 20 to 5 ml/min.) may be given 10 percent of the normal daily dose every 24 hours. all dosage recommendations apply after an initial loading dose. reconstitution preparation of parenteral solution: parenteral drug products should be shaken well when reconstituted , and inspected visually for particulate matter prior to administration. if particulate matter is evident in reconstituted fluids, the drug solutions should be discarded. when reconstituted or diluted according to the instructions below, cefazolin for injection, usp is stable for 24 hours at room temperature or for 10 days if stored under refrigeration (5°c or 41 °f). reconstituted solutions may range in color from pale yellow to yellow without a change in potency. single-dose vials: for im injection, iv direct (bolus) injection or iv infusion, reconstitute with sterile water for injection according to the following table. shake well. vial size amount of diluent approximate concentration approximate available volume 1 gram 2.5 ml 330 mg/ml 3.0 ml 2 grams 5 ml 330 mg/ml 6.0 ml administration intramuscular administration: reconstitute vials with sterile water for injection according to the dilution table above. shake well until dissolved. cefazolin for injection, usp should be injected into a large muscle mass. pain on injection is infrequent with cefazolin for injection, usp. intravenous administration: direct (bolus) injection: following reconstitution according to the above table, further dilute vials with approximately 5 ml sterile water for injection. inject the solution slowly over 3 to 5 minutes, directly or through tubing for patients receiving parenteral fluids (see list below). intermittent or continuous infusion: dilute reconstituted cefazolin for injection, usp in 50 to 100 ml of 1 of the following solutions: sodium chloride injection, usp 5% or 10% dextrose injection, usp 5% dextrose in lactated ringer's injection, usp 5% dextrose and 0.9% sodium chloride injection, usp 5% dextrose and 0.45% sodium chloride injection, usp 5% dextrose and 0.2% sodium chloride injection, usp lactated ringer's injection, usp invert sugar 5% or 10% in sterile water for injection ringer's injection, usp 5% sodium bicarbonate injection, usp

ion has occurred. other reactions: genital and anal pruritus (including vulvar pruritus, genital moniliasis, and vaginitis). to report suspected adverse reactions, contact fda at 1-800-fda-1088 or www.fda.gov/medwatch .

hospitalized with infections indicate that cefazolin for injection, usp produces mean peak serum levels approximately equivalent to those seen in normal volunteers. bile levels in patients without obstructive biliary disease can reach or exceed serum levels by up to 5 times; however, in patients with obstructive biliary disease, bile levels of cefazolin for injection, usp are considerably lower than serum levels (< 1.0 mcg/ml). in synovial fluid, the level of cefazolin for injection, usp becomes comparable to that reached in serum at about 4 hours after drug administration. studies of cord blood show prompt transfer of cefazolin for injection, usp across the placenta. cefazolin for injection, usp is present in very low concentrations in the milk of nursing mothers. cefazolin for injection, usp is excreted unchanged in the urine. in the first 6 hours approximately 60% of the drug is excreted in the urine and this increases to 70% to 80% within 24 hours. cefazolin for injection, usp achieves peak urine concentrations of approximately 2,400 mcg/ml and 4,000 mcg/ml respectively following 500-mg and 1-gram intramuscular doses. in patients undergoing peritoneal dialysis (2 l/hr.), cefazolin for injection, usp produced mean serum levels of approximately 10 and 30 mcg/ml after 24 hours’ instillation of a dialyzing solution containing 50 mg/l and 150 mg/l, respectively. mean peak levels were 29 mcg/ml (range 13 to 44 mcg/ml) with 50 mg/l (3 patients), and 72 mcg/ml (range 26 to 142 mcg/ml) with 150 mg/l (6 patients). intraperitoneal administration of cefazolin for injection, usp is usually well tolerated. controlled studies on adult normal volunteers, receiving 1 gram 4 times a day for 10 days, monitoring cbc, sgot, sgpt, bilirubin, alkaline phosphatase, bun, creatinine, and urinalysis, indicated no clinically significant changes attributed to cefazolin for injection, usp. microbiology mechanism of action cefazolin is a bactericidal agent that acts by inhibition of bacterial cell wall synthesis. resistance predominant mechanisms of bacterial resistance to cephalosporins include the presence of extended-spectrum beta-lactamases and enzymatic hydrolysis. antimicrobial activity cefazolin has been shown to be active against most isolates of the following microorganisms, both in vitro and in clinical infections as described in the indications and usage section. gram-positive bacteria staphylococcus aureus staphylococcus epidermidis streptococcus agalactiae streptococcus pneumoniae streptococcus pyogenes methicillin-resistant staphylococci are uniformly resistant to cefazolin. gram-negative bacteria escherichia coli proteus mirabilis most isolates of indole positive proteus ( proteus vulgaris ), enterobacter spp., morganella morganii , providencia rettgeri , serratia spp., and pseudomonas spp. are resistant to cefazolin. 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.