Cefazolin is a first-generation cephalosporin antibiotic used to treat and prevent infections caused by susceptible bacteria. Its indications are classified below by strength of evidence.

Established/FDA-approved uses

Surgical prophylaxis — prevention of postoperative infection in clean and clean-contaminated surgical procedures
Skin and soft tissue infections caused by susceptible Staphylococcus aureus and Streptococcus species
Respiratory tract infections due to susceptible Streptococcus pneumoniae, Staphylococcus aureus, and Klebsiella pneumoniae
Urinary tract infections caused by susceptible E. coli, Proteus mirabilis, and Klebsiella species
Biliary tract infections caused by susceptible E. coli, streptococci, and Staphylococcus aureus
Bone and joint infections caused by susceptible S. aureus
Bacterial endocarditis and bacteremia/septicemia caused by susceptible organisms

Guideline-supported / adjunct uses

Endocarditis prophylaxis in select high-risk procedures as an alternative agent in patients without severe penicillin allergy, per cardiology society guidance
Combination therapy with an aminoglycoside or other agent for certain polymicrobial or severe infections requiring broader coverage

Cefazolin is not effective against methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, or most gram-negative anaerobes. Culture and susceptibility testing should guide therapy whenever possible.

Dosage & Administration of Cefazolin

Dosage of Cefazolin is individualized according to the site and severity of infection, susceptibility of the causative organism, and renal function.

Adult dosing by indication

Indication	Usual adult dose
Mild to moderate infections (skin/soft tissue, respiratory, biliary, urinary)	250 mg–1 g IV or IM every 8 hours
Moderate to severe infections	500 mg–1 g IV or IM every 6–8 hours
Severe, life-threatening infections (e.g., endocarditis, bacteremia)	1–1.5 g IV every 6 hours (up to 12 g/day under close monitoring)
Uncomplicated urinary tract infection	1 g IV or IM every 12 hours
Surgical prophylaxis	1–2 g IV within 60 minutes before incision; an additional intraoperative dose if surgery exceeds 4 hours or with major blood loss; a higher weight-based dose may be used in obese patients per institutional protocol

Pediatric dosing (over 1 month of age)

25–100 mg/kg/day IV or IM in 3–4 divided doses depending on severity of infection, not exceeding the maximum adult dose. Safety and efficacy in neonates (under 1 month) have not been established.

Renal impairment

Cefazolin is renally cleared and dosage must be reduced in renal impairment based on creatinine clearance; a physician or pharmacist should individualize adjustment. Patients on hemodialysis require a supplemental dose after each dialysis session.

Administration

Cefazolin may be given by direct slow IV injection, intermittent IV infusion in a compatible diluent, or deep intramuscular injection. It must be reconstituted/diluted as directed before use (see Reconstitution).

Important: Receive Cefazolin exactly as prescribed by your physician; do not stop, extend, skip doses, or share this medicine with others without medical advice.

Side Effects of Cefazolin

The most commonly reported adverse effects of Cefazolin include:

Injection site reactions: pain, induration, phlebitis (IV); pain and induration (IM)
Gastrointestinal: nausea, vomiting, diarrhea, abdominal pain
Hypersensitivity reactions: rash, pruritus, urticaria, drug fever
Hematologic: eosinophilia, transient elevations in liver enzymes (AST/ALT), transient leukopenia or thrombocytopenia
Genitourinary: vaginal candidiasis/pruritus

Less common but serious effects include Clostridioides difficile-associated diarrhea/colitis (which can occur during or after treatment with Cefazolin, even weeks post-discontinuation), anaphylaxis and other severe hypersensitivity reactions, and, rarely, seizures with very high doses of Cefazolin, particularly in patients with renal impairment. Seek prompt medical attention for severe or persistent symptoms.

Contraindications of Cefazolin

Cefazolin is contraindicated in patients with:

Known hypersensitivity (including anaphylaxis or other severe reactions) to Cefazolin or any other cephalosporin antibiotic

Patients with a history of severe, immediate-type hypersensitivity (e.g., anaphylaxis, angioedema) to penicillins or other beta-lactam antibiotics should receive Cefazolin only with caution and close monitoring (see Precautions and Warnings), as this is a relative rather than absolute contraindication.

Frequently Asked Questions about Cefazolin

What is Cefazolin used for?

Cefazolin is a first-generation cephalosporin antibiotic used to prevent infection during surgery and to treat infections of the skin, respiratory tract, urinary tract, biliary tract, bones/joints, and bloodstream caused by susceptible bacteria.

How is Cefazolin given?

Cefazolin is given by a healthcare professional as an intravenous (IV) injection or infusion, or as an intramuscular (IM) injection. It is not taken by mouth.

Can Cefazolin be used if I am allergic to penicillin?

Cefazolin belongs to a related but distinct antibiotic class (cephalosporins). The risk of cross-reactivity with penicillin allergy is lower than once believed, but if you have a history of a severe or immediate allergic reaction (such as anaphylaxis) to penicillin, tell your doctor before receiving Cefazolin, as caution and close monitoring are needed.

Is Cefazolin safe during pregnancy and breastfeeding?

Cefazolin should be used during pregnancy only if clearly needed, as animal studies have not shown fetal harm but adequate human studies are limited; discuss potential benefits and risks with your physician. Cefazolin passes into breast milk in small amounts, so your baby should be monitored for effects such as diarrhea or thrush if you are breastfeeding while receiving Cefazolin.

What should I do if I develop diarrhea during treatment?

Cefazolin should be given exactly as prescribed; do not stop, extend, skip doses, or share this medicine with others. Contact your doctor promptly if you develop diarrhea during or after treatment with Cefazolin, as this could be a sign of a Clostridioides difficile infection requiring evaluation.

What are the common side effects of Cefazolin?

Common side effects of Cefazolin include pain or irritation at the injection site, nausea, vomiting, diarrhea, and allergic skin reactions such as rash or itching. Seek immediate medical attention if you experience signs of a severe allergic reaction, such as difficulty breathing or swelling of the face/throat.

Disclaimer

The information provided is accurate to the best of our knowledge, but it does not replace professional medical advice. We cannot guarantee its completeness or accuracy, and the absence of specific information about a drug should not be taken as an endorsement. We are not responsible for any consequences arising from this information, so please consult a healthcare professional for any concerns or questions.

Cefazolin: Brands, Price & Uses in Bangladesh

Zolibac500 mg/5 m

Zolibac1 gm/5 ml

About Cefazolin

Indications of Cefazolin