Skip to Content
Looking to save on your medications?  Find out how 


Generic name: cefazolin systemic

Brand names: Ancef, Kefzol

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product

Solution, Intravenous [preservative free]:

Generic: 1 g/50 mL in Dextrose 4% (50 mL); 2 g/100 mL in Dextrose 4% (100 mL)

Solution Reconstituted, Injection:

Generic: 500 mg (1 ea [DSC]); 10 g (1 ea)

Solution Reconstituted, Injection [preservative free]:

Generic: 500 mg (1 ea); 1 g (1 ea); 10 g (1 ea); 20 g (1 ea [DSC]); 100 g (1 ea); 300 g (1 ea)

Solution Reconstituted, Intravenous [preservative free]:

Generic: 1 g (1 ea); 1 g and Dextrose 4% (1 ea); 2 g and Dextrose 3% (1 ea)


Mechanism of Action

Inhibits bacterial cell wall synthesis by binding to one or more of the penicillin-binding proteins (PBPs) which in turn inhibits the final transpeptidation step of peptidoglycan synthesis in bacterial cell walls, thus inhibiting cell wall biosynthesis. Bacteria eventually lyse due to ongoing activity of cell wall autolytic enzymes (autolysins and murein hydrolases) while cell wall assembly is arrested.



Widely into most body tissues and fluids including gallbladder, liver, kidneys, bone, sputum, bile, pleural, and synovial; CSF penetration is poor


Urine (70% to 80% as unchanged drug)

Time to Peak

Serum: IM: 0.5 to 2 hours; IV: Within 5 minutes

Half-Life Elimination

IM or IV: Neonates: 3 to 5 hours; Adults: 1.8 hours (IV); ~2 hours (IM) (prolonged with renal impairment)

Protein Binding

80% (Marshall 1999)

Use: Labeled Indications

Biliary tract infection: Treatment of biliary tract infections due to Escherichia coli, various strains of streptococci, Proteus mirabilis, Klebsiella species, and Staphylococcus aureus.

Bloodstream infection: Treatment of bloodstream infection due to methicillin-susceptible staphylococci, E. coli, P. mirabilis, and Klebsiella species.

Bone and joint infection: Treatment of bone and joint infections due to S. aureus.

Endocarditis, treatment: Treatment of endocarditis due to methicillin-susceptible staphylococci and group A beta-hemolytic streptococci (Streptococcus pyogenes).

Genital infection: Treatment of genital infections (ie, prostatitis, epididymitis) due to E. coli, P. mirabilis, and Klebsiella species.

Respiratory tract infection: Treatment of respiratory tract infections due to Streptococcus pneumoniae, Klebsiella species, Haemophilus influenzae, methicillin-susceptible S. aureus, and group A beta-hemolytic streptococci.

Skin and soft tissue infection: Treatment of skin and soft tissue infections due to methicillin-susceptible S. aureus, group A beta-hemolytic streptococci, and other strains of streptococci.

Surgical prophylaxis: To reduce the incidence of certain postoperative infections in patients undergoing surgical procedures.

Urinary tract infection: Treatment of urinary tract infections due to E. coli, P. mirabilis, Klebsiella species, and some strains of Enterobacter.

Use: Off Label

Endocarditis, prophylaxisyes

Based on the American Heart Association guidelines for the prevention of infective endocarditis, cefazolin is an effective and recommended alternative agent for prophylaxis against infective endocarditis associated with dental or respiratory tract procedures in patients with certain cardiac conditions who have a non-severe, non-IgE-mediated penicillin allergy who cannot take oral medication.

Peritonitis, treatment (peritoneal dialysis patients)yes

Based on the International Society for Peritoneal Dialysis peritonitis recommendations: 2016 update on prevention and treatment, intraperitoneal cefazolin is an effective and recommended component of empiric therapy in patients at low risk for methicillin-resistant Staphylococcus aureus or as pathogen-directed therapy for peritonitis associated with peritoneal dialysis.

Streptococcus (group B), maternal prophylaxis for prevention of neonatal diseaseyes

Based on the American College of Obstetricians and Gynecologists prevention of group B streptococcal early-onset disease in newborns guideline, cefazolin is an effective and recommended alternative agent at the onset of labor and until delivery in mothers colonized with group B streptococcus (neonatal prophylaxis) who are penicillin allergic and at low risk for anaphylaxis (eg, no history of angioedema, respiratory distress, or urticaria).

Toxic shock syndromec

Clinical experience suggests the utility of cefazolin in the treatment of toxic shock syndrome caused by group A streptococcus and methicillin-susceptible S. aureus Chu 2019, Stevens 2019.


Hypersensitivity to cefazolin, other cephalosporin antibiotics, penicillins, other beta-lactams, or any component of the formulation.

Dosage and Administration

Dosing: Adult

Bloodstream infection:

Pathogen-directed therapy for methicillin-susceptible staphylococci (alternative agent):

IV: 2 g every 8 hours (Fowler 2019; IDSA [Mermel 2009]); treat uncomplicated Staphylococcus aureus bacteremia for ≥14 days starting from day of first negative blood culture, with longer courses warranted for endocarditis or metastatic sites of infection (IDSA [Mermel 2009]).

Pathogen-directed therapy for susceptible Enterobacteriaceae:

IV: 2 g every 8 hours (Hsieh 2016; Turnidge 2011). Usual duration is 7 to 14 days; individualize depending on source and extent of infection as well as clinical response. A 7-day duration is recommended for patients with uncomplicated Enterobacteriaceae infection who respond appropriately to antibiotic therapy (Moehring 2019; Yahav 2018).

Antibiotic lock technique (catheter-salvage strategy):

Note: For infections caused by susceptible organisms when the catheter cannot be removed; use in addition to systemic antibiotics. Catheter salvage is not recommended for S. aureus. Prepare lock solution to final concentration of cefazolin 5 mg/mL (may be combined with heparin). Instill into each lumen of the catheter access port using a volume sufficient to fill the catheter (2 to 5 mL), with a dwell time of up to 72 hours depending on frequency of catheter use. Withdraw lock solution prior to catheter use; replace with fresh cefazolin lock solution after catheter use. Antibiotic lock therapy is given for the same duration as systemic antibiotics (Bookstaver 2009; IDSA [Mermel 2009]).

Endocarditis, prophylaxis (dental or invasive respiratory tract procedures) (alternative agent for patients with nonsevere, non-IgE-mediated penicillin allergy who cannot take oral therapy) (off-label use):

IM, IV: 1 g as a single dose 30 to 60 minutes before procedure. Note: Only recommended for patients with cardiac conditions associated with the highest risk of adverse outcome from endocarditis and who are undergoing a procedure likely to result in bacteremia with an organism that has the potential ability to cause endocarditis (AHA [Wilson 2007]).

Endocarditis, treatment:

Note: Cefazolin should not be used in patients with concomitant CNS infections (eg, brain abscess) (AHA [Baddour 2015]).

Pathogen-directed therapy for methicillin-susceptible staphylococci (alternative agent for patients with nonsevere, non-IgE-mediated penicillin allergy):

Native valve: IV: 2 g every 8 hours for 6 weeks (AHA [Baddour 2015]).

Prosthetic valve: IV: 2 g every 8 hours for ≥6 weeks (combine with rifampin for entire duration of therapy and gentamicin for the first 2 weeks) (AHA [Baddour 2015]).

Intra-abdominal infection, community-acquired (mild to moderate infection in low-risk patients):

Note: Reserve for patients with low risk for resistant pathogens (eg, local Enterobacteriaceae resistance rate to cefazolin <10% and no recent antibiotic exposure) (Barshak 2019).

Cholecystitis, acute: IV: 1 to 2 g every 8 hours; continue for 1 day after gallbladder removal or until clinical resolution in patients managed nonoperatively (IDSA/SIS [Solomkin 2010]; Vollmer 2019). Note: The addition of anaerobic therapy is recommended if biliary-enteric anastomosis is present (IDSA/SIS [Solomkin 2010]).

Other intra-abdominal infections (eg, perforated appendix, appendiceal abscess, diverticulitis) (off-label use): IV: 1 to 2 g every 8 hours in combination with metronidazole. Total duration of therapy (which may include oral step-down therapy) is 4 to 7 days following adequate source control (IDSA/SIS [Solomkin 2010]); for uncomplicated appendicitis managed nonoperatively, a longer duration may be necessary (Barshak 2019; Pemberton 2019; Salminen 2015).

Osteomyelitis and/or discitis:

Treatment, pathogen-directed therapy for methicillin-susceptible S. aureus:

IV: 2 g every 8 hours for ≥6 weeks depending on extent of infection, debridement, and clinical response (IDSA [Berbari 2015]; Osmon 2019).

Prevention, following open fractures:

IV: 2 g for patients <120 kg or 3 g for patients ≥120 kg every 8 hours; ideally administer within 6 hours of injury. For type I or II fractures (no more than moderate comminution or contamination, no or minimal periosteal stripping, adequate soft tissue coverage), discontinue 24 hours following wound closure. For type III fractures (severe contamination or comminution), use as part of an appropriate combination regimen and continue for 72 hours after injury or up to 24 hours after wound closure (EAST [Hoff 2011]; Schmitt 2019). Note: For patients with risk for methicillin-resistant S. aureus (MRSA), potential water exposure, or fecal or clostridial contamination, alternative or additional antibiotics are recommended (Schmitt 2019).

Peritonitis, treatment (peritoneal dialysis patients) (off-label use):

Note: As a component of empiric therapy in patients at low risk for MRSA or as pathogen-directed therapy. Intraperitoneal administration is preferred to IV administration. Duration of therapy is ≥2 to 3 weeks, depending on organism, for patients with adequate clinical response (Burkart 2019; ISPD [Li 2016]). Consider a 25% dose increase in patients with significant residual renal function (urine output >100 mL/day) (ISPD [Li 2010]; ISPD [Li 2016]; Mancini 2018; Szeto 2018).

Intermittent: Intraperitoneal: 15 to 20 mg/kg added to one exchange of dialysis solution once daily (allow to dwell for ≥6 hours). For patients on continuous ambulatory peritoneal dialysis, add cefazolin to the overnight dwell. Note: Some experts recommend adding cefazolin to each exchange in patients on automated peritoneal dialysis as nighttime intraperitoneal levels of cefazolin may fall below the minimum inhibitory concentration of most organisms (ISPD [Li 2016]).

Continuous (with every exchange) (dose is per liter of dialysate): Intraperitoneal: Loading dose: 500 mg/L of dialysate added to first exchange of dialysate; maintenance dose: 125 mg/L of dialysate with each subsequent exchange of dialysate (ISPD [Li 2016]).

Pneumonia: Pathogen-directed therapy for methicillin-susceptible S. aureus: IV: 2 g every 8 hours (Klompas 2019; Miller 2018). Minimum duration is 5 to 7 days; patients should be afebrile for ≥48 hours and clinically stable before therapy is discontinued (IDSA/ATS [Kalil 2016]; IDSA/ATS [Mandell 2007]).

Prostatitis, acute bacterial: Pathogen-directed therapy for susceptible organisms: IV: 1 g every 8 hours; may switch to oral therapy 24 to 48 hours after improvement in fever and clinical symptoms. Total duration of therapy is 6 weeks (Meyrier 2019).

Prosthetic joint infection: Pathogen-directed therapy for methicillin-susceptible S. aureus: IV: 2 g every 8 hours. Duration ranges from 2 to 6 weeks depending on prosthesis management, use of rifampin, and other patient-specific factors. Note: In select cases (eg, debridement and retention of prosthesis or one-stage arthroplasty), combine with oral rifampin and give oral suppressive antibiotic therapy following completion of IV treatment (Berbari 2019; IDSA [Osmon 2013]).

Septic arthritis, without prosthetic material: Pathogen-directed therapy for methicillin-susceptible S. aureus: IV: 2 g every 8 hours. Duration is 3 to 4 weeks (in the absence of osteomyelitis), including oral step-down therapy (Goldenberg 2019; Ross 2017). Some experts recommend 4 weeks of parenteral therapy for patients with concomitant bacteremia (Goldenberg 2019).

Skin and soft tissue infection:

Erysipelas or nonpurulent cellulitis in patients without risk for methicillin-resistant S. aureus: IV: 1 to 2 g every 8 hours. Total duration of therapy ≥5 days (including oral step-down therapy); may extend to 14 days depending on severity and clinical response (IDSA [Stevens 2014]; Spelman 2019).

Pathogen-directed therapy for methicillin-susceptible S. aureus: IV: 1 to 2 g every 8 hours. Total duration of therapy is 5 to 14 days (including oral step-down therapy) depending on severity of infection, need for debridement, and clinical response (IDSA [Stevens 2014]; Spelman 2019). Note: For necrotizing infections, antibiotic therapy must be used in conjunction with early and aggressive surgical exploration and debridement of necrotic tissue; continue until further debridement is not necessary and the patient has clinically improved and is afebrile for 48 to 72 hours (IDSA [Stevens 2014]).

Surgical site incisional infection (trunk or extremity surgery, not involving axilla or perineum): IV: 1 g every 8 hours; duration is dependent upon severity, need for debridement, and clinical response (IDSA [Stevens 2014]).

Streptococcus (group B), maternal prophylaxis for prevention of neonatal disease (alternative agent) (off-label use):

Note: Prophylaxis is reserved for pregnant women with a positive group B streptococcus (GBS) vaginal or rectal screening in late gestation or GBS bacteriuria during the current pregnancy, history of birth of an infant with early-onset GBS disease, and unknown GBS culture status with any of the following: birth <37 0/7 weeks gestation, intrapartum fever, prolonged rupture of membranes, known GBS positive in a previous pregnancy, or intrapartum nucleic acid amplification testing positive for GBS (ACOG 782 2019).

IV: 2 g as a single dose at onset of labor or prelabor rupture of membranes, then 1 g every 8 hours until delivery (ACOG 782 2019). Note: Use of cefazolin should be reserved for penicillin-allergic patients at low risk for anaphylaxis (eg, rash without urticaria and no systemic symptoms, family history of penicillin allergy but no personal history, patients who report penicillin allergy but have no recollection of symptoms or treatment) (ACOG 782 2019).

Surgical prophylaxis: IV: 2 g for patients <120 kg or 3 g for patients ≥120 kg; administer within 60 minutes of surgical incision. Use in combination with metronidazole for procedures requiring anaerobic coverage (eg, colorectal and clean-contaminated head and neck procedures). May repeat dose intraoperatively in 4 hours if procedure is lengthy or if there is excessive blood loss (ASHP/IDSA/SIS/SHEA [Bratzler 2013]); maximum dose: 12 g/day (manufacturer's labeling). In cases where an extension of prophylaxis is warranted postoperatively, total duration should be ≤24 hours (Anderson 2014). Postoperative prophylaxis is not recommended in clean and clean-contaminated surgeries (CDC [Berríos-Torres 2017]).

Toxic shock syndrome (off-label use): Pathogen-directed therapy for group A streptococcus or methicillin-susceptible S. aureus (alternative agent for patients with nonsevere, non-IgE-mediated penicillin allergy) (off-label use): IV: 2 g every 8 hours in combination with clindamycin. In the absence of bacteremia, treat for a total of ≥10 days, including oral step-down therapy (Chu 2019; Stevens 2019).

Urinary tract infection, complicated (including pyelonephritis): Pathogen-directed therapy for susceptible organisms: IV: 1 g every 8 hours (Millar 1995; Wing 1998). Switch to an appropriate oral regimen once patient has improvement in symptoms if culture and susceptibility results allow. Duration of therapy depends on the antimicrobial chosen to complete the regimen and ranges from 5 to 14 days (IDSA [Gupta 2011]; IDSA [Hooton 2010]).

Dosing: Geriatric

Refer to adult dosing.

Dosing: Pediatric

General dosing, susceptible infection (Bradley 2019; Red Book [AAP 2018]): Infants, Children, and Adolescents: IM, IV:

Mild to moderate infections: 25 to 100 mg/kg/day divided every 8 hours; maximum daily dose: 6 g/day

Severe infections (eg, bone/joint infections): 100 to 150 mg/kg/day divided every 6 to 8 hours; maximum daily dose: 12 g/day

Endocarditis, bacterial:

Prophylaxis for dental and upper respiratory procedures: Infants, Children, and Adolescents: IM, IV: 50 mg/kg 30 to 60 minutes before procedure; maximum dose: 1,000 mg/dose (AHA [Wilson 2007]). Note: AHA guidelines (Baltimore 2015) limit the use of prophylactic antibiotics to patients at the highest risk for infective endocarditis (IE) or adverse outcomes (eg, prosthetic heart valves, patients with previous IE, unrepaired cyanotic congenital heart disease, repaired congenital heart disease with prosthetic material or device during first 6 months after procedure, repaired congenital heart disease with residual defects at the site or adjacent to site of prosthetic patch or device, and heart transplant recipients with cardiac valvulopathy).

Treatment: Children and Adolescents: IV: 100 mg/kg/day in divided doses every 8 hours; usual adult dose: 2,000 mg/dose; maximum daily dose: 12 g/day; treat for at least 4 weeks; longer durations may be necessary; may use with or without gentamicin (AHA [Baltimore 2015])

Peritonitis (peritoneal dialysis) (ISPD [Warady 2012]): Limited data available: Infants, Children, and Adolescents:


Touch contamination of PD line: Intraperitoneal: 125 mg per liter

Invasive dental procedures: IV: 25 mg/kg administered 30 to 60 minutes before procedure; maximum dose: 1,000 mg/dose

Gastrointestinal or genitourinary procedures: IV: 25 mg/kg administered 60 minutes before procedure; maximum dose: 2,000 mg/dose

Treatment: Intraperitoneal:

Intermittent: 20 mg/kg every 24 hours in the long dwell

Continuous: Loading dose: 500 mg per liter of dialysate; maintenance: 125 mg per liter of dialysate

Pneumonia, community-acquired pneumonia (CAP), S. aureus, methicillin susceptible: Infants >3 months, Children, and Adolescents: IV: 50 mg/kg/dose every 8 hours (Bradley 2011); usual maximum dose for severe infections: 12 g/day (Red Book [AAP 2018])

Skin and soft tissue infections, S. aureus, methicillin susceptible (mild to moderate): (IDSA [Stevens 2014]): Infants, Children, and Adolescents:

S. aureus, methicillin susceptible skin and soft tissue infections including pyomyositis: IV: 50 mg/kg/day divided every 8 hours; maximum dose: 1,000 mg/dose; higher doses may be required in severe cases; duration of therapy at least 5 days, but longer may be necessary in some cases, eg, febrile and neutropenic patients: 7 to 14 days; pyomyositis: 14 to 21 days

S. aureus, methicillin susceptible necrotizing infection of skin, fascia, or muscle: IV: 100 mg/kg/day divided every 8 hours; maximum dose: 1,000 mg/dose; continue therapy until surgical debridement no longer necessary, clinical improvement and afebrile for 48 to 72 hours

Streptococcal, nonpurulent skin infection (cellulitis): IV: 100 mg/kg/day divided every 8 hours; maximum dose: 1,000 mg/dose; duration of therapy at least 5 days, but longer may be necessary in some cases

Surgical prophylaxis: Infants, Children, and Adolescents: IV: 30 mg/kg within 60 minutes prior to procedure, may repeat in 4 hours for prolonged procedure or excessive blood loss (eg, >1,500 mL in adults); maximum dose dependent upon patient weight: Weight <120 kg: 2,000 mg/dose; weight ≥120 kg: 3,000 mg/dose (ASHP/IDSA [Bratzler 2013]; Red Book [AAP 2018])

Dosing: Obesity

Refer to indication-specific dosing for obesity-related information (may not be available for all indications).


Dilute 500 mg vial with 2 mL SWFI and 1 g vial with 2.5 mL SWFI; reconstituted solution may be directly injected after further dilution with 5 mL SWFI or further diluted for IV administration in 50 to 100 mL compatible solution (eg, D5W, NS); 10 g vial may be diluted with 45 mL to yield 1 g/5 mL or 96 mL to yield 1 g/10 mL.


IM: Inject deep IM into large muscle mass.

IV: Inject direct IV over 3 to 5 minutes or may infuse as an intermittent infusion over 30 to 60 minutes.

Some penicillins (eg, carbenicillin, ticarcillin and piperacillin) have been shown to inactivate aminoglycosides in vitro. This has been observed to a greater extent with tobramycin and gentamicin, while amikacin has shown greater stability against inactivation. Concurrent use of these agents may pose a risk of reduced antibacterial efficacy in vivo, particularly in the setting of profound renal impairment. However, definitive clinical evidence is lacking. If combination penicillin/aminoglycoside therapy is desired in a patient with renal dysfunction, separation of doses (if feasible), and routine monitoring of aminoglycoside levels, CBC, and clinical response should be considered.

Dietary Considerations

Some products may contain sodium.


Store intact vials at room temperature and protect from temperatures exceeding 40°C. Reconstituted solutions of cefazolin are light yellow to yellow. Protection from light is recommended for the powder and for the reconstituted solutions. Reconstituted solutions are stable for 24 hours at room temperature and for 10 days under refrigeration. Stability of parenteral admixture in D5W, D5LR, D51/4NS, D51/2NS, D5NS, D10W, LR, or NS at room temperature (25°C) is 48 hours. Stability of parenteral admixture at refrigeration temperature (4°C) is 14 days.

DUPLEX: Store at 20°C to 25°C (68°F to 77°F); excursions permitted to 15°C to 30°C (59°F to 86°F) prior to activation. Following activation, stable for 24 hours at room temperature and for 7 days under refrigeration.

GALAXY: Store at or below -20°C (-4°F). Thawed solution stable for 48 hours at room temperature and for 30 days under refrigeration. Do not refreeze.

Drug Interactions

BCG (Intravesical): Antibiotics may diminish the therapeutic effect of BCG (Intravesical). Avoid combination

BCG Vaccine (Immunization): Antibiotics may diminish the therapeutic effect of BCG Vaccine (Immunization). Monitor therapy

Cholera Vaccine: Antibiotics may diminish the therapeutic effect of Cholera Vaccine. Management: Avoid cholera vaccine in patients receiving systemic antibiotics, and within 14 days following the use of oral or parenteral antibiotics. Avoid combination

Fosphenytoin: CeFAZolin may decrease the protein binding of Fosphenytoin. Monitor therapy

Lactobacillus and Estriol: Antibiotics may diminish the therapeutic effect of Lactobacillus and Estriol. Monitor therapy

Phenytoin: CeFAZolin may decrease the protein binding of Phenytoin. Monitor therapy

Probenecid: May increase the serum concentration of Cephalosporins. Monitor therapy

RifAMPin: CeFAZolin may enhance the adverse/toxic effect of RifAMPin. Specifically, the risk for bleeding may be increased. Management: Avoid concomitant use of rifampin with cefazolin when possible. If combined, closely monitor prothrombin time or other coagulation tests and administer vitamin K as needed. Consider therapy modification

Sodium Picosulfate: Antibiotics may diminish the therapeutic effect of Sodium Picosulfate. Management: Consider using an alternative product for bowel cleansing prior to a colonoscopy in patients who have recently used or are concurrently using an antibiotic. Consider therapy modification

Typhoid Vaccine: Antibiotics may diminish the therapeutic effect of Typhoid Vaccine. Only the live attenuated Ty21a strain is affected. Management: Vaccination with live attenuated typhoid vaccine (Ty21a) should be avoided in patients being treated with systemic antibacterial agents. Use of this vaccine should be postponed until at least 3 days after cessation of antibacterial agents. Consider therapy modification

Vitamin K Antagonists (eg, warfarin): Cephalosporins may enhance the anticoagulant effect of Vitamin K Antagonists. Monitor therapy

Test Interactions

Positive direct and indirect Coombs', false-positive urinary glucose test using cupric sulfate (Benedict's solution, Clinitest, Fehling's solution), false-positive serum or urine creatinine with Jaffé reaction.

Some penicillin derivatives may accelerate the degradation of aminoglycosides in vitro, leading to a potential underestimation of aminoglycoside serum concentration.

Adverse Reactions

Frequency not defined.

Cardiovascular: Localized phlebitis

Central nervous system: Seizure

Dermatologic: Pruritus, skin rash, Stevens-Johnson syndrome

Gastrointestinal: Abdominal cramps, anorexia, diarrhea, nausea, oral candidiasis, pseudomembranous colitis, vomiting

Genitourinary: Vaginitis

Hepatic: Hepatitis, increased serum transaminases

Hematologic: Eosinophilia, leukopenia, neutropenia, thrombocythemia, thrombocytopenia

Hypersensitivity: Anaphylaxis

Local: Pain at injection site

Renal: Increased blood urea nitrogen, increased serum creatinine, renal failure

Miscellaneous: Fever


Concerns related to adverse effects:

  • Elevated INR: May be associated with increased INR, especially in nutritionally-deficient patients, prolonged treatment, hepatic or renal disease.
  • Hypersensitivity reactions: Hypersensitivity reactions, including anaphylaxis, may occur. If an allergic reaction occurs, discontinue treatment and institute appropriate supportive measures.
  • Penicillin allergy: Use with caution in patients with a history of penicillin allergy.
  • Superinfection: Prolonged use may result in fungal or bacterial superinfection, including Clostridioides (formerly Clostridium) difficile-associated diarrhea (CDAD) and pseudomembranous colitis; CDAD has been observed >2 months postantibiotic treatment.

Disease-related concerns:

  • Gastrointestinal disease: Use with caution in patients with a history of gastrointestinal disease, particularly colitis.
  • Renal impairment: Use with caution in patients with renal impairment; dosage adjustment required.
  • Seizure disorders: Use with caution in patients with a history of seizure disorder; high levels, particularly in the presence of renal impairment, may increase risk of seizures.

Concurrent drug therapy issues:

  • Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.

Monitoring Parameters

Renal function periodically, hepatic function tests, CBC; monitor for signs of anaphylaxis during first dose


Pregnancy Risk Factor


Pregnancy Considerations

Cefazolin crosses the placenta.

Adverse events have not been reported in the fetus following administration of cefazolin prior to cesarean delivery.

Due to pregnancy-induced physiologic changes, some pharmacokinetic parameters of cefazolin may be altered (Allegaert 2009; Elkomy 2014; Philipson 1987). In addition to pregnancy, obesity has been found to influence the pharmacokinetics of cefazolin (Pevzner 2011; Stitely 2013; Young 2015). Dose adjustments may be required in pregnant women who are obese (ACOG 199 2018).

Cefazolin is recommended for group B streptococcus prophylaxis in pregnant patients with a nonanaphylactic penicillin allergy. It is also one of the antibiotics recommended for prophylactic use prior to cesarean delivery and may be used in certain situations prior to vaginal delivery in women at high risk for endocarditis (ACOG 199 2018; ACOG 782 2019).

Patient Education

What is this drug used for?

  • It is used to treat or prevent bacterial infections.

Frequently reported side effects of this drug

  • Diarrhea
  • Nausea
  • Vomiting
  • Lack of appetite

Other side effects of this drug: Talk with your doctor right away if you have any of these signs of:

  • Liver problems like dark urine, fatigue, lack of appetite, nausea, abdominal pain, light-colored stools, vomiting, or yellow skin.
  • Kidney problems like unable to pass urine, blood in the urine, change in amount of urine passed, or weight gain.
  • Bruising
  • Bleeding
  • Thrush
  • Chills
  • Sore throat
  • Severe loss of strength and energy
  • Seizures
  • Anal irritation
  • Vaginal pain, itching, and discharge
  • Stevens-Johnson syndrome/toxic epidermal necrolysis like red, swollen, blistered, or peeling skin (with or without fever); red or irritated eyes; or sores in mouth, throat, nose, or eyes.
  • Clostridioides (formerly Clostridium difficile-associated) diarrhea like abdominal pain or cramps, severe diarrhea or watery stools, or bloody stools.
  • Signs of a significant reaction like wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat.

Note: This is not a comprehensive list of all side effects. Talk to your doctor if you have questions.

Consumer Information Use and Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from the healthcare provider. You must talk with the healthcare provider for complete information about the risks and benefits of using this medicine.

Source: Wolters Kluwer Health. Last updated January 14, 2020.