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Cefazolin Injection

(sef a' zoe lin)

Brand Name(s): Ancef®, Kefzol®; also available generically

WHY is this medicine prescribed?

Cefazolin injection is used to treat certain infections caused by bacteria including skin, bone, joint, genital, blood, heart valve, respiratory tract (including pneumonia), biliary tract, and urinary tract infections. Cefazolin injection also may be used before, during, and sometimes for a brief period after surgery in order to prevent the patient from getting an infection. Cefazolin injection is in a class of medications called cephalosporin antibiotics. It works by killing bacteria.

Antibiotics such as cefazolin injection will not work for colds, flu, or other viral infections. Taking antibiotics when they are not needed increases your risk of getting an infection later that resists antibiotic treatment.

Are there OTHER USES for this medicine?

Cefazolin injection is also sometimes used for certain penicillin allergic patients who have a heart condition and are having a dental or upper respiratory tract (nose, mouth, throat, voice box) procedure, in order to prevent them from developing a heart valve infection. Cefazolin injection is also sometimes used to treat certain penicillin allergic women who are in labor in order to prevent the newborn from developing an infection.

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

HOW should this medicine be used?

Cefazolin injection comes as a powder to be mixed with liquid, or as a premixed product, to be injected intravenously (into a vein) over a period of 30 minutes. Cefazolin injection can also be given intramuscularly (into a muscle). It is usually given every 6, 8, or 12 hours. The length of your treatment depends on the type of infection you have and how your body responds to the medication.

You may receive cefazolin injection in a hospital or you may administer the medication at home. If you will be receiving cefazolin injection at home, your healthcare provider will show you how to use the medication. Be sure that you understand these directions, and ask your healthcare provider if you have any questions.

You should begin to feel better during the first few days of treatment with cefazolin injection. If your symptoms do not improve or get worse, call your doctor.

Use cefazolin injection until you finish the prescription, even if you feel better. If you stop using cefazolin injection too soon or skip doses, your infection may not be completely treated and the bacteria may become resistant to antibiotics.

What SPECIAL PRECAUTIONS should I follow?

Before taking cefazolin injection,

  • tell your doctor and pharmacist if you are allergic to cefazolin; carbapenem antibiotics; other cephalosporin antibiotics such as cefaclor, cefadroxil, cefdinir, cefditoren (Spectracef), cefepime (Maxipime), cefixime (Suprax), cefotaxime (Claforan), cefotetan, cefoxitin (Mefoxin), cefpodoxime, cefprozil, ceftaroline (Teflaro), ceftazidime (Fortaz, Tazicef, in Avycaz), ceftibuten (Cedax), ceftriaxone (Rocephin), cefuroxime (Zinacef), and cephalexin (Keflex); penicillin antibiotics; or any other medications. Also tell your doctor if you are allergic to any of the ingredients in cefazolin injection. Ask your pharmacist for a list of the ingredients.
  • tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention probenecid (Probalan). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
  • tell your doctor if you have or have ever had gastrointestinal disease (GI; affecting the stomach or intestines), especially colitis (condition that causes swelling in the lining of the colon [large intestine]), or kidney disease.
  • tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while taking cefazolin injection, call your doctor.

What SPECIAL DIETARY instructions should I follow?

Unless your doctor tells you otherwise, continue your normal diet.

What should I do IF I FORGET to take a dose?

Use the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not use a double dose to make up for a missed one.

What SIDE EFFECTS can this medicine cause?

Cefazolin injection may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • genital itching
  • white patches in mouth
  • loss of appetite
  • heartburn
  • gas
  • nausea
  • vomiting
  • diarrhea
  • headache
  • dizziness
  • confusion
  • weakness
  • tiredness
  • drowsiness
  • pain, redness, swelling, or bleeding near the place where cefazolin was injected

Some side effects can be serious. If you experience any of these symptoms, stop taking cefazolin injection and call your doctor immediately or get emergency medical treatment:

  • watery or bloody stools, stomach cramps or fever during treatment or for up to two or more months after stopping treatment
  • rash
  • hives
  • itching
  • difficulty breathing or swallowing
  • blistering, peeling, or shedding skin
  • swelling in legs and feet
  • decreased urination
  • dark urine
  • yellowing of skin or eyes
  • pain in the upper right part of stomach
  • fainting
  • a return of fever, sore throat, chills, or other signs of infection

Cefazolin injection may cause other side effects. Call your doctor if you have any unusual problems while using this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

What should I know about STORAGE and DISPOSAL of this medication?

Your healthcare provider will tell you how to store your medication. Store your medication only as directed. Make sure you understand how to store your medication properly.

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

What should I do in case of OVERDOSE?

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

Symptoms of overdose may include the following:

  • seizures

What OTHER INFORMATION should I know?

Keep all appointments with your doctor and the laboratory. Your doctor may order certain lab tests to check your body's response to cefazolin injection.

Before having any laboratory test, tell your doctor and the laboratory personnel that you are taking cefazolin injection.

If you are diabetic and test your urine for sugar, use Clinistix or TesTape (not Clinitest) to test your urine while taking this medication.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.


This report on medications is for your information only, and is not considered individual patient advice. Because of the changing nature of drug information, please consult your physician or pharmacist about specific clinical use.

The American Society of Health-System Pharmacists® represents that the information provided hereunder was formulated with a reasonable standard of care, and in conformity with professional standards in the field. The American Society of Health-System Pharmacists® makes no representations or warranties, express or implied, including, but not limited to, any implied warranty of merchantability and/or fitness for a particular purpose, with respect to such information and specifically disclaims all such warranties. Users are advised that decisions regarding drug therapy are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and the information is provided for informational purposes only. The entire monograph for a drug should be reviewed for a thorough understanding of the drug's actions, uses and side effects. The American Society of Health-System Pharmacists® does not endorse or recommend the use of any drug. The information is not a substitute for medical care.

Pronunciation Guide for Drug Names is used with permission. © 2009. The United States Pharmacopeial Convention. All Rights Reserved.

AHFS® Patient Medication Information™. © Copyright, 2020. The American Society of Health-System Pharmacists®, 4500 East-West Highway, Suite 900, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

Selected Revisions: June 15, 2016.