cefazolin sodium
Ancef, Kefzol
Therapeutic classification: antibiotic
Pregnancy risk category B
Available forms
Available by prescription only
Infusion: 500-mg or 1-g Redi Vials, Faspaks, or ADD-Vantage vials
Injection (parenteral): 250 mg, 500 mg, 1 g
Indications and dosages 
Serious respiratory, GU, skin, soft-tissue, bone, and joint infections; biliary tract infections; septicemia; endocarditis
from susceptible organisms; perioperative prophylaxis; contaminated surgery ◇. Adults: 250 mg I.M. or I.V. q 8 hours to 1 g q 8 hours. Maximum daily dose is 12 g in life-threatening situations.
Children older than age 1 month: 25 to 100 mg/kg I.M. or I.V. daily in divided doses q 8 hours.
Total daily dose is same for I.M. or I.V. administration and depends on the susceptibility of organism and severity of infection.
Inject cefazolin deep I.M. into a large muscle mass, such as the gluteus or the lateral aspect of the thigh.
≡ Dosage adjustment. Dose or frequency of administration must be modified according to the degree of renal impairment, severity of infection,
susceptibility of organism, and serum levels of drug. Because drug can be removed by hemodialysis, patients undergoing hemodialysis
may need a dosage adjustment.
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Pharmacodynamics
Antibacterial action: Cefazolin is primarily bactericidal; it also may be bacteriostatic. Activity depends on the organism, tissue penetration,
dosage, and rate of organism multiplication. It acts by adhering to bacterial penicillin-binding proteins, thereby inhibiting
cell wall synthesis.
Cefazolin is active against Escherichia coli, Enterobacteriaceae, Haemophilus influenzae, Klebsiella,Proteus mirabilis, Staphylococcus aureus, Streptococcus pneumoniae, and group A beta-hemolytic streptococci.
Pharmacokinetics
Absorption: Not well absorbed from the GI tract; must be given parenterally.
Distribution: Distributed widely into most body tissues and fluids, including the gallbladder, liver, kidneys, bone, sputum, bile, and
pleural and synovial fluids; CSF penetration is poor. It crosses the placental barrier and is 74% to 86% protein-bound.
Metabolism: Not metabolized.
Excretion: Excreted primarily unchanged in urine by renal tubular secretion and glomerular filtration; small amounts of drug appear
in breast milk. Elimination half-life is about 1 to 2 hours in patients with normal renal function; end-stage renal disease
prolongs half-life to 12 to 50 hours. Hemodialysis or peritoneal dialysis removes cefazolin.
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Contraindications and precautions
Contraindicated in patients hypersensitive to other cephalosporins. Use cautiously in breast-feeding women and patients with
impaired renal function or penicillin allergy.
Interactions
Drug-drug. Bacteriostatic drugs (chloramphenicol, erythromycin, tetracyclines): May interfere with bactericidal activity. Avoid use together.
Loop diuretics, nephrotoxic drugs (aminoglycosides, colistin, polymyxin B, vancomycin): May increase risk of nephrotoxicity. Monitor patient closely.
Probenecid: Competitively inhibits renal tubular secretion of cephalosporins, resulting in higher, prolonged serum levels of these drugs. Monitor patient closely.
Adverse reactions
CV: phlebitis, thrombophlebitis (with I.V. injection).
GI: pseudomembranous colitis, nausea, anorexia, vomiting, diarrhea, glossitis, dyspepsia, abdominal cramps, anal pruritus, oral candidiasis.
GU: genital pruritus, candidiasis, vaginitis.
Hematologic: neutropenia, leukopenia, eosinophilia, thrombocytopenia.
Skin: maculopapular and erythematous rashes, urticaria, pruritus, Stevens-Johnson syndrome; pain, induration, sterile abscesses, tissue sloughing (at injection site).
Other: hypersensitivity reactions (serum sickness, anaphylaxis).
Effects on lab test results
• May increase ALT, AST, alkaline phosphatase, bilirubin, GGT, and LDH levels.
• May increase eosinophil count. May decrease neutrophil, WBC, and platelet counts.
Overdose and treatment
Overdose may cause neuromuscular hypersensitivity; seizures may follow high CNS levels.
Cefazolin may be removed by hemodialysis.
Special considerations
• For I.M. use, reconstitute with sterile water, bacteriostatic water, or normal saline solution: 2 ml to a 500-mg vial and
2.5 ml to a 1-g vial produces 225 mg/ml, and 330 mg/ml, respectively.
• I.M. cefazolin injection is less painful than that of other cephalosporins.
• Reconstituted solution is stable for 24 hours at room temperature and for 10 days if refrigerated.
• Cephalosporins cause false-positive results in urine glucose tests using cupric sulfate (Benedict’s reagent or Clinitest);
use glucose oxidase tests (Chemstrip uG, Diastix, or glucose enzymatic test strip) instead. Cefazolin causes false elevations
in serum or urine creatinine levels in tests using Jaffe reaction. Cefazolin also causes positive Coombs’ test results.
• For patients on sodium restriction, note that cefazolin injection contains 2 mEq of sodium per gram of drug.
• Obtain electrolyte studies.
• If patient has renal impairment, monitor renal function tests.
Breast-feeding patients
• Safety hasn’t been established. Use drug cautiously in breast-feeding women.
Pediatric patients
• Drug has been used in children. However, safety in infants younger than age 1 month hasn’t been established.
Patient education
• Inform patient of potential adverse reactions.
Reactions may be common, uncommon, life-threatening, or
COMMON AND LIFE THREATENING.
◆ Canada only
◇ Unlabeled clinical use