Cefazolin (Injection)

Cefazolin, known in the marketplace under the name brand of Ancef, is used in the treatment of infections that are bacterial in nature


Cefazolin is an antibiotic drug that is injected into patients who are suffering from various infections caused by bacteria. Cefazolin works on skin, joint, blood, genital, bone, heart valve, urinary tract, biliary tract and respiratory infections and may also be used as a preventive form of therapy given during surgery, as well as prior to and post surgery.

Cefazolin does not work for viral infections, such as influenza or the common cold. If an antibiotic like Cefazolin is taken too often when it is not needed, the body can form a resistance to it over time, which makes treating bacterial infections more difficult.

How does Cefazolin work?

Cefazolin is an antibiotic from the cephalosporin family. It kills bacteria by disrupting the enzymes that build the essential cell wall around the bacteria. By disrupting the synthesis of this structure, Cefazolin eventually causes the death of the bacteria and the end of the infection, meaning that the body can heal.

What is a bacterial infection?

There are hundreds of thousands of bacteria strains, and the majority of them are harmless or even beneficial. Occasionally, though, some are harmful and difficult to get rid of. These are known as pathogenic bacteria. Pathogenic bacteria contribute to global outbreaks of diseases, such as tuberculosis, pneumonia and salmonella. Some enter the body through a cut or through a compromised immune system; others enter through the food or water supply.

Condition(s) treated

  • Bacterial infections, including infections of the skin, joints, blood, genitals, bones, heart valves, urinary tract, biliary tract and respiratory system

Type of medicine

  • Antibiotic

Side effects

By attacking the cell wall structure itself, Cefazolin is able to eliminate bacteria from an infected patient. At times, the properties that make Cefazolin effective against bacterial infection also give the patient unwanted illnesses that are associated. Most patients have no problems while taking Cefazolin, but if should the following side effects crop up, contact your physician or nurse immediately:

  • Blue tinge to skin
  • Skin changes in color
  • Pain or tenderness in various places
  • Swollen feet or legs
  • Abdominal cramps
  • Tender stomach
  • Stools that resemble black tar or clay in color
  • Gums that bleed
  • Loose, peeling or blistered skin
  • Bloated feeling
  • Urine or stools showing signs of blood
  • Urine that is dark, cloudy or bloody
  • Pain in the chest area
  • Chills
  • Productive cough with blood
  • Dry cough
  • Urine output is less than normal or less frequent
  • Severe diarrhea that may also show blood
  • Urination that is painful or difficult
  • Swallowing or breathing is difficult
  • Dizzy
  • Muscle tone appears excessive
  • Rapid pulse
  • General uncomfortable feeling
  • Tired, weak, fatigued
  • Hives
  • Headache
  • Blood pressure is higher than normal
  • Menstrual flow is heavier
  • Thirsty
  • Joints are inflamed
  • Genital itching
  • Muscle pain or joint pain
  • Little to no appetite
  • Pain in side or lower back
  • Stiffness, tension, tightness or aches in muscles
  • Vomiting
  • Nausea
  • Nosebleeds
  • Painful sex
  • Burning, warm, painful fingers, toes or legs
  • Skin is pale
  • Partial or complete paralysis
  • Tiny red dots in a rash on the skin
  • Hearing or vision problems
  • Cuts that do not heal
  • Swollen, puffy eyes, face, tongue or lips
  • Skin rash
  • Eyes are irritated or red
  • Skin lesions, often red with purple centers
  • Seizures
  • Restlessness
  • Sore throat
  • White spots, ulcers or sores on the mouth or lips
  • Cramps in stomach
  • Swollen lower legs, fingers or face
  • Lymph glands are painful or swollen
  • Vaginal discharge that is odorless, white, thick or with a mild odor
  • Halitosis (chronic bad breath)
  • Chest tightness
  • Bruising or bleeding that is unexpected
  • Loss of weight that is unexplained
  • Pain in the upper right abdomen
  • Vomiting, possibly with blood
  • Gaining weight
  • Skin or eyes that are tinged yellow

Some side effects, though annoying, are typically temporary and will pass with time. Others are mild and can be eased with home remedies that your health care professional can advise you on.

If you experience the following effects after being given Cefazolin, check with a medical professional if they become prolonged or severe:

  • The injection site becomes red, bleeds, has a lump or rash, stings, is swollen or tender
  • Welts on the skin
  • Hives
  • Red skin
  • Tongue or mouth is sore
  • Loss of weight
  • Throat, mouth or tongue has white patches


Cefazolin is an injected antibiotic medication that is only administered by a trained health care professional, such as a doctor or nurse. Your dosage will vary depending on your condition. Follow your health care provider's instructions after being given an injection of Cefazolin.


You may be allergic to antibiotics such as Cefazolin; if you have ever had any strange side effects after being given antibiotics or any other drugs, you should inform your physician that you may be allergic. Other types of allergies, including allergies to preservatives, foods, animals or colorings, could also indicate that you will be allergic to Cefazolin.

As with any drug, it is important to disclose your medical history to your health care provider prior to treatment. This includes any prescriptions you may be taking, as well as vitamin supplements, herbal or holistic remedies and non-prescription drugs, such as pain relievers.

Medications are occasionally prescribed together if they can both be beneficial when acting at the same time. There are, however, medications that do not interact well together and, for this reason, should be avoided in order to insure the safety of the patient.

If you are being given Cefazolin, avoiding a live vaccine for cholera disease is absolutely mandatory for your ultimate health and safety. Additionally, use of Warfarin while being treated with Cefazolin is not advised, but may be approved by your medical professional if this treatment is required.

Studies on pregnant women and women who are breastfeeding have not shown any risk to the fetus or child. It is best to discuss the use of this antibiotic with your doctor if you are pregnant, may become pregnant, or are breastfeeding, to make the best decision for you and your baby.

Cefazolin has been shown to cause a life threatening, toxic reaction in studies of its use on newborn and premature babies. Caution should be taken when children of any age use this drug. Elderly patients, who are at a higher risk for kidney function problems, should also be cautious when taking Cefazolin.

The use of alcoholic beverages, tobacco products and even certain foods could cause an interaction with Cefazolin, which may range from harmful to merely bothersome. Discuss these substances and their use with this drug with your physician for specific recommendations.

Medical problems, such as the ones listed below, may have an effect on how Cefazolin is used by your system. Make sure you inform your health care provider if you have been diagnosed with:

  • Liver disease
  • Kidney disease
  • Malnourishment
  • Bowel issues or stomach disease, such as colitis
  • Seizure disorders

These conditions may be made worse with use of Cefazolin, so full disclosure of your medical history is advised before you undergo this drug treatment.


While you are being treated with Cefazolin, your symptoms of bacterial infection should begin to show improvement within a day or two. If they do not or if they worsen, contact your doctor immediately.

This medication may cause you to have diarrhea which, for some patients, can be severe in nature. Do not take any medication that is designed for the treatment of diarrhea without checking with your physician or nurse. These medicines may worsen the case of diarrhea or prolong the symptom.

Medical tests given to you at this time may not have results as expected, due to the Cefazolin found in your system. For this reason, any doctors treating you should be aware that you have had this medication prior to any tests being done. This warning includes dental professionals, who may also need to know about your treatment with Cefazolin for various reasons. If you are diabetic, some urine glucose testing kits may not give accurate readings during your treatment with Cefazolin.

Medications that include calcium, over the counter medicines and vitamin or herbal supplements should not be taken with Cefazolin unless approved by your doctor first.

Patients who are 65 or older may experience more side effects or find side effects are more severe with use of Cefazolin. Use of this medication in geriatric patients should be done with caution.

If you are pregnant or planning to become pregnant, discuss use of Cefazolin with your health care provider in detail to determine if it is the best treatment for you at this time.

Patients with kidney disease in particular should be warned that, due to the reduced speed of removal from the body because of their condition, side effects may increase.


Cefazolin is administered only in a hospital or medical clinic setting and is stored per the manufacturer's instructions by the medical staff providing treatment.


Cefazolin is an antibiotic drug from the cephalosporin family that is available only through an injection administered by your doctor. This medication is used for treatment and prevention of bacterial infections; it will not have any effect on influenza or other viral infections, such as the common cold. Cefazolin is only administered in a hospital setting; the patient will not be responsible for storage or dosing of this drug for any reason.

Side effects are wide ranging but include skin issues, internal bleeding, kidney and liver problems, as well as stomach upset and diarrhea. Severe diarrhea is a particular risk and may be watery or include blood. Any side effects that are severe in nature or prolonged in duration should be reported to your physician as soon as possible, to prevent long term health implications.

Patients with diabetes should not rely on their urine test kit to give them accurate readings while being treated with Cefazolin. Any doctors or dentists that give you medical tests for any reason should be advised that you have had Cefazolin, as the results may not come back as expected. It is warned strongly not to use Warfarin while on this medication, nor should you receive a live vaccination for the cholera virus during treatment, to prevent any health risks.

Patients who have been diagnosed with malnutrition, stomach ailments, bowel, kidney or liver disease should use Cefazolin with extreme caution, as these conditions could worsen with use of this drug.

Last Reviewed:
December 23, 2017
Last Updated:
April 04, 2018