Dosing & Uses
Dosage Forms & Strengths
powder for injection
- 500mg
- 1g
- 2g
- 10g
- 20g
- 100g
- 300g
Moderate-to-Severe Infections
0.5-1 g IV q6-8hr
Mild Infections With Gram-Positive Cocci
250-500 mg IV q8hr
Mild-to-Moderate Cholecystitis
1-2 g IV q8hr for 4-7 days
Uncomplicated Urinary Tract Infection
1 g IV q12hr
Preparation for Surgery
Prophylaxis against infection
Preoperatively: 1-2 g IV/IM ≤60 minutes before procedure (may be repeated in 2-5 hours intraoperatively)
Postoperatively: 0.5-1 g IV q6-8hr for 24 hours
Surgical infection
- Cardiac procedures, hysterectomy, oral or pharyngeal procedures, craniotomy, joint replacement, thoracic procedures, arterial procedures, amputation, traumatic wounds; high-risk esophageal, gastroduodenal, or biliary tract procedures: 1-2 g IV
- Colorectal procedures: 1-2 g IV plus metronidazole 0.5 g IV
- High-risk cesarean section, 2nd trimester abortion: 1 g IV
- Ophthalmic procedures: 100 mg subconjunctivally
Endocarditis
- 1 g IV/IM 30-60 minutes before procedure
- American Heart Association (AHA) guidelines: Endocarditis prophylaxis recommended only for high-risk patients
Bacterial Keratitis (Off-label)
1 drop instilled into affected eye(s) q1-2hr; typically alternated every other hour with antibiotic providing gram-negative coverage (eg, tobramycin)
Extemporaneous compounded fortified cefazolin 50 mg/mL
- Dilute 500 mg parenteral cefazolin powder in sterile water to form 10 mL solution
- Store refrigerated; preparation expires in 7 days
Dosing Modifications
Renal impairment
- CrCl 35-54 mL/min: Give full dose at intervals >8hr
- CrCl 10-35 mL/min: Give therapeutic dose q12hr
- CrCl ≤10 mL/min: Give therapeutic dose q24hr
Hepatic impairment
- Not studied
Dosing Considerations
Susceptible organisms
- Streptococcus pneumoniae, Klebsiella, Haemophilus influenzae, Staphylococcus aureus, group A beta-hemolytic streptococcus, Escherichia coli, Proteus mirabilis, Enterobacter (some strains)
Dosage Forms & Strengths
powder for injection
- 500mg
- 1g
- 2g
- 10g
- 20g
- 100g
- 300g
Infections With Gram-Positive Cocci
Neonates (<28 days)
- <7 days: 40 mg/kg/day IV/IM divided q12hr
- >7 days, <2 kg: 40 mg/kg/day IV/IM divided q12hr
- >7 days, >2 kg: 60 mg/kg/day IV/IM divided q8hr
Infants & children
- 25-100 mg/kg/day IV/IM divided q6-8hr; not to exceed 6 g/day
Endocarditis
Prophylaxis
50 mg/kg IV/IM ≤30-60 minutes before procedure; not to exceed 1 g
AHA guidelines: Endocarditis prophylaxis recommended only for high-risk patients
Community-Acquired Pneumonia
>3 months and children: 150 mg/kg/day IV/IM divided q8hr (moderate to severe infections, methicillin susceptible S.Aureus preferred
Dosing Considerations
Cefazolin 2 g for Injection USP and Dextrose Injection USP is not recommended for use in pediatric patients; to avoid unintentional overdose, 1 g cefazolin for Injection USP and dextrose Injection USP should only be used in pediatric patients who require entire contents of 1 g dose and not any fraction of it
There are no dosing recommendations for pediatric patients for perioperative prophylaxis or for pediatric patients with renal impairment
Interactions
Interaction Checker
No Results

Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor

Contraindicated (0)
Serious - Use Alternative (12)
- antithrombin alfa
cefazolin increases effects of antithrombin alfa by pharmacodynamic synergism. Avoid or Use Alternate Drug.
- antithrombin III
cefazolin increases effects of antithrombin III by pharmacodynamic synergism. Avoid or Use Alternate Drug.
- argatroban
cefazolin increases effects of argatroban by pharmacodynamic synergism. Avoid or Use Alternate Drug.
- BCG vaccine live
cefazolin decreases effects of BCG vaccine live by pharmacodynamic antagonism. Contraindicated. Wait until Abx Tx complete to administer live bacterial vaccine.
- bivalirudin
cefazolin increases effects of bivalirudin by pharmacodynamic synergism. Avoid or Use Alternate Drug.
- cholera vaccine
cefazolin, cholera vaccine. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Avoid coadministration of cholera vaccine with systemic antibiotics since these agents may be active against the vaccine strain. Do not administer cholera vaccine to patients who have received oral or parenteral antibiotics within 14 days prior to vaccination.
- dalteparin
cefazolin increases effects of dalteparin by pharmacodynamic synergism. Avoid or Use Alternate Drug.
- enoxaparin
cefazolin increases effects of enoxaparin by pharmacodynamic synergism. Avoid or Use Alternate Drug.
- fondaparinux
cefazolin increases effects of fondaparinux by pharmacodynamic synergism. Avoid or Use Alternate Drug.
- heparin
cefazolin increases effects of heparin by pharmacodynamic synergism. Avoid or Use Alternate Drug.
- microbiota oral
cefazolin decreases effects of microbiota oral by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Microbiota oral contains bacterial spores. Antibacterial agents may decrease efficacy if coadministered. Complete antibiotic regimens 2-4 days before initiating microbiota oral. .
- typhoid vaccine live
cefazolin decreases effects of typhoid vaccine live by pharmacodynamic antagonism. Contraindicated. Wait until Abx Tx complete to administer live bacterial vaccine.
Monitor Closely (9)
- bazedoxifene/conjugated estrogens
cefazolin will decrease the level or effect of bazedoxifene/conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.
- dienogest/estradiol valerate
cefazolin will decrease the level or effect of dienogest/estradiol valerate by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor. An alternate or additional form of birth control may be advisable during concomitant use.
- estradiol
cefazolin will decrease the level or effect of estradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.
- ethinylestradiol
cefazolin will decrease the level or effect of ethinylestradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.
- levonorgestrel oral/ethinylestradiol/ferrous bisglycinate
cefazolin will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor. Antibiotics may decrease hormonal contraceptive efficacy.
- probenecid
probenecid increases levels of cefazolin by acidic (anionic) drug competition for renal tubular clearance. Use Caution/Monitor.
- sodium picosulfate/magnesium oxide/anhydrous citric acid
cefazolin decreases effects of sodium picosulfate/magnesium oxide/anhydrous citric acid by altering metabolism. Use Caution/Monitor. Coadministration with antibiotics decreases efficacy by altering colonic bacterial flora needed to convert sodium picosulfate to active drug.
- voclosporin
voclosporin, cefazolin. Either increases toxicity of the other by nephrotoxicity and/or ototoxicity. Modify Therapy/Monitor Closely. Coadministration with drugs associated with nephrotoxicity may increase the risk for acute and/or chronic nephrotoxicity.
- warfarin
cefazolin increases effects of warfarin by unspecified interaction mechanism. Use Caution/Monitor.
Minor (9)
- aspirin/citric acid/sodium bicarbonate
cefazolin will increase the level or effect of aspirin/citric acid/sodium bicarbonate by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- biotin
cefazolin will decrease the level or effect of biotin by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.
- chloramphenicol
chloramphenicol decreases effects of cefazolin by pharmacodynamic antagonism. Minor/Significance Unknown.
- furosemide
cefazolin increases toxicity of furosemide by pharmacodynamic synergism. Minor/Significance Unknown. Increased risk of nephrotoxicity.
- ketorolac intranasal
cefazolin will increase the level or effect of ketorolac intranasal by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- pyridoxine (Antidote)
cefazolin will decrease the level or effect of pyridoxine (Antidote) by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.
- rose hips
rose hips will increase the level or effect of cefazolin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- sulfasalazine
cefazolin will increase the level or effect of sulfasalazine by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- willow bark
cefazolin will increase the level or effect of willow bark by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
Adverse Effects
Frequency Not Defined
Anorexia
Diarrhea
Eosinophilia
Fever
Increased transaminases
Leukopenia
Nausea and vomiting
Neutropenia
Oral candidiasis
Pain at injection site
Phlebitis
Pseudomembranous colitis
Seizure
Stevens-Johnson syndrome
Thrombocytopenia
Thrombocytosis
Transient elevation of hepatic enzymes
Vaginitis
Postmarketing Reports
Immune system disorders: Serum sickness-like reaction
Renal and urinary disorders: Acute tubulointerstitial nephritis
Skin and subcutaneous tissue disorders: Acute generalized exanthematous pustulosis (AGEP)
Warnings
Contraindications
Documented hypersensitivity
Cautions
Endocarditis prophylaxis recommended only for high-risk patients, per AHA guidelines
Prolonged treatment, hepatic or renal disease, or nutritional deficiency may be associated with increased international normalized ratio (INR)
Use with caution in patients with seizure disorder (high levels are associated with increased risk of seizures); seizures may occur, particularly in patients with renal impairment when dosage is not reduced appropriately; dose must be adjusted in severe renal insufficiency (high doses may cause CNS toxicity); discontinue if seizures occur or make appropriate dosage adjustments in patients with renal impairment; continue anticonvulsant therapy in patients with known seizure disorders
Prescribing cefazolin injection in absence of proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases risk of development of drug-resistant bacteria
As with other antimicrobials, prolonged use of cefazolin injection may result in overgrowth of nonsusceptible microorganisms; repeated evaluation of the patient's condition is essential; should superinfection occur during therapy, appropriate measures should be taken
Therapy may result in a false-positive reaction with glucose in urine when using glucose tests based on Benedict’s copper reduction reaction that determine amount of reducing substances like glucose in urine; it is recommended that glucose tests based on enzymatic glucose oxidase be used
Hypersensitivity reactions, including anaphylaxis, reported with administration of dextrose-containing products; these reactions have been reported in patients receiving high concentrations of dextrose (i.e. 50% dextrose); reactions have been reported when corn-derived dextrose solutions were administered to patients with or without a history of hypersensitivity to corn products
As with other dextrose-containing solutions, cefazolin injection should be prescribed with caution in patients with overt or known subclinical diabetes mellitus or carbohydrate intolerance for any reason
Antibiotic associated diarrhea
- Clostridioides difficile-associated diarrhea (CDAD) reported with use; may range in severity from mild diarrhea to fatal colitis; treatment with antibacterial agents alters normal flora of colon leading to overgrowth of C. difficile
- C. difficile produces toxins A and B, which contribute to development of CDAD; hypertoxin-producing isolates of C. difficile cause increased morbidity and mortality, as these infections can be refractory to antimicrobial therapy and may require colectomy
- CDAD must be considered in all patients who present with diarrhea following antibacterial drug use; careful medical history is necessary since CDAD has been reported to occur over two months after administration of antibacterial agents
- If CDAD is suspected or confirmed, ongoing antibacterial drug use not directed against C. difficile may need to be discontinued; appropriate fluid and electrolyte management, protein supplementation, antibacterial drug treatment of C. difficile, and surgical evaluation instituted as clinically indicated
Pregnancy & Lactation
Pregnancy
Available data from published prospective cohort studies, case series and case reports over several decades with cephalosporin use, including cefazolin, in pregnant women have not established a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes; drug crosses the placenta
Animal data
- Animal reproduction studies with rats, mice and rabbits administered cefazolin during organogenesis at doses 1 to 3 times maximum recommended human dose (MRHD) did not demonstrate adverse developmental outcomes; in rats subcutaneously administered cefazolin prior to delivery and throughout lactation, there were no adverse effects on offspring at a dose approximately 2 times the MRHD
Lactation
Data from published literature report that cefazolin is present in human milk, but not expected to accumulate in a breastfed infant; there are no data on effects of drug on breastfed child or on milk production
Developmental and health benefits of breastfeeding should be considered along with mother’s clinical need for therapy and any potential adverse effects on breastfed child from drug or from the mother’s underlying condition
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
First-generation semisynthetic cephalosporin that binds to 1 or more penicillin-binding proteins, thereby arresting bacterial cell-wall synthesis and inhibiting bacterial replication; has poor capacity to cross blood-brain barrier; primarily active against skin flora, including S aureus
Absorption
Peak plasma time: 0.5-2 hr (IM); 5 min (IV)
Distribution
Crosses placenta; penetrates CSF poorly
Protein bound: 74-86%
Metabolism
Minimally metabolized in liver
Elimination
Half-life: 90-150 min
Excretion: Urine (80-100% as unchanged drug)
Administration
IV and IM dosing regimens are similar; drug is primarily active against skin flora, including S aureus, and is typically used alone for skin and skin-structure coverage
IV Incompatibilities
Additive: Amikacin, gentamicin
Syringe: Cimetidine, lidocaine
Y-site: Amiodarone(?), amphotericin B
Not specified: Erythromycin, norepinephrine, pentobarbital, tetracycline
IV Compatibilities
Additive: Cimetidine, verapamil
Y-site: Aminophylline, amiodarone(?), calcium gluconate, lidocaine, vitamins B and C
Not specified: Ampicillin, diazepam, hydrocortisone, potassium chloride
IV Preparation
Reconstitute 500 mg or 1 g with 2 mL or 2.5 mL SWI, respectively, to provide solutions containing approximately 225 or 330 mg/mL
IV push: Further dilute in approximately 5 mL of SWI or according to manufacturer's directions
Infusion: Dilute reconstituted 500 mg or 1 g solution in 50-100 mL NS or D5W
IM Preparation
Reconstitute 500 mg or 1 g with 2 mL or 2.5 mL SWI, respectively, to provide solutions containing approximately 225 or 330 mg/mL
IV Administration
IV push
- Administer directly into vein, and infuse over 3-5 minutes or slowly into tubing of compatible IV infusion solution
- Solution is usually light-yellow to yellow
- Discard if precipitate is present
Infusion: volume control set or piggyback container
- IV infusion stable for 24 hours at room temperature and 96 hours refrigerated
IM Administration
Inject deep into large muscle mass
Images
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cefazolin injection - | 1 gram vial | ![]() | |
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cefazolin injection - | 1 gram vial | ![]() | |
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cefazolin injection - | 500 mg vial | ![]() | |
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cefazolin injection - | 500 mg vial | ![]() | |
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cefazolin injection - | 500 mg vial | ![]() | |
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cefazolin injection - | 1 gram vial | ![]() | |
cefazolin injection - | 500 mg vial | ![]() | |
cefazolin injection - | 500 mg vial | ![]() | |
cefazolin injection - | 10 gram vial | ![]() | |
cefazolin injection - | 10 gram vial | ![]() | |
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Copyright © 2010 First DataBank, Inc.
Patient Handout
cefazolin injection
CEFAZOLIN - INJECTION
(sef-A-zoe-lin)
COMMON BRAND NAME(S): Ancef
USES: Cefazolin is an antibiotic used to treat a wide variety of bacterial infections. It may also be used before and during certain surgeries to help prevent infection. This medication is known as a cephalosporin antibiotic. It works by stopping the growth of bacteria.
HOW TO USE: Depending on your specific product, this medication is given by injection into a vein or into a muscle. Use this product exactly as directed by your doctor. The dosage is based on your medical condition and response to treatment. For children, the dosage is also based on their weight.If you are giving this medication to yourself at home, learn all preparation and usage instructions from your health care professional. Before using, check this product visually for particles or discoloration. If either is present, do not use the liquid. Learn how to store and discard medical supplies safely.For the best effect, use this antibiotic at evenly spaced times. To help you remember, use this medication at the same time(s) every day.Continue to use this medication until the full prescribed treatment period is finished, even if symptoms disappear after a few days. Stopping the medication too early may result in a return of the infection.Tell your doctor if your condition lasts or gets worse.
SIDE EFFECTS: Swelling, redness, pain, or soreness at the injection site may occur. This medication may also rarely cause loss of appetite, nausea, vomiting, diarrhea, or headache. If any of these effects last or get worse, tell your doctor or pharmacist promptly.Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.Tell your doctor right away if you have any serious side effects, including: dark urine, easy bruising/bleeding, fast/pounding/irregular heartbeat, seizures, unusual weakness, yellowing eyes/skin, mental/mood changes (such as confusion).This medication may rarely cause a severe intestinal condition due to a bacteria called C. difficile. This condition may occur during treatment or weeks to months after treatment has stopped. Tell your doctor right away if you develop: diarrhea that doesn't stop, abdominal or stomach pain/cramping, blood/mucus in your stool.If you have these symptoms, do not use anti-diarrhea or opioid products because they may make symptoms worse.Use of this medication for prolonged or repeated periods may result in oral thrush or a new vaginal yeast infection. Contact your doctor if you notice white patches in your mouth, a change in vaginal discharge, or other new symptoms.A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
PRECAUTIONS: Before using cefazolin, tell your doctor or pharmacist if you are allergic to it; or to other cephalosporins; or to penicillins; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney disease, liver disease, stomach/intestinal diseases (such as colitis).Cefazolin may cause live bacterial vaccines (such as typhoid vaccine) to not work well. Tell your health care professional that you are using cefazolin before having any immunizations/vaccinations.Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).Tell your doctor if you are pregnant before using this medication.This medication passes into breast milk. Consult your doctor before breast-feeding.
DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.This medication may interfere with certain lab tests (including Coombs' test, certain urine glucose tests), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.
OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: trouble breathing, seizures.
NOTES: Do not share this medication with others.This medication has been prescribed for your current condition only. Do not use it later for another infection unless your doctor tells you to.Lab and/or medical tests (such as complete blood count or kidney function) may be done while you are using this product. Keep all medical and lab appointments. Consult your doctor for more details.
MISSED DOSE: It is important to get each dose of this medication as scheduled. If you miss a dose, ask your doctor or pharmacist right away for a new dosing schedule. Do not double the dose to catch up.
STORAGE: Consult the product instructions and your pharmacist for storage details. Keep all medications away from children and pets.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.
Information last revised March 2023. Copyright(c) 2023 First Databank, Inc.
IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.
Formulary
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