Antibiotics Before and After Surgery

Understanding Antibiotics and Their Use In Surgery

Surgical Incision Neck, Thyroid Incision, Cervical Spine Incision, Cervical Spine Scar,
Incisions Can Become Infected After Surgery. © Getty Images/Phil Banko

Antibiotics are often used before and after surgery for a variety of reasons.  They may be used to treat an infection before surgery, to prevent infection, or to treat an infection after surgery.  

There are many types of antibiotics available today, and they vary in how they are administered, what they treat best, how much is given and for how long.  There is a tremendous amount of research done every year on how antibiotics should be used, and a patient who received an antibiotic for a condition one year may find they are being a different dose or a different medication for the same condition a year later.


Surgery For Infection

If you are having surgery to treat an infection, you are mostly likely to be given an antibiotic before and after surgery, perhaps even during the procedure.  You may be given antibiotics that will be given as pills that you take by mouth or the medication might be given through an IV, or both.

Prophylactic Antibiotics

The word prophylactic means “preventative.”  A prophylactic antibiotic is given to prevent an infection, rather than to treat one.  This is typically done when a procedure is known to have a high likelihood of causing serious infection.  

An excellent example of this is when a patient with a known heart valve condition is determined to at risk for a serious heart valve infection called infective endocarditis.  For this very small population, taking an antibiotic before a dental or upper respiratory tract procedure can prevent a very serious complication.


The typical patient would not need prophylactic antibiotics to go to the dentist, but for this small group of people, a single dose of antibiotic could prevent damage to the heart.  In this case, the reward (no infection) outweighs the risks (side effects of antibiotics).

Antibiotic Treatment

Except in cases where prophylactic antibiotics are necessary, antibiotics are typically given when there is a strong suspicion or proof of bacterial infection.

Viruses cannot be treated with antibiotic therapy, so it is important to know that the treatment is appropriate for the condition.  For example, bronchitis is typically a viral condition, so it is not treated with antibiotics.  A bacterial infection, such as a infected incision, would be treated with antibiotic therapy.

One common way to determine if an infection is present is to obtain a culture.  This means collecting a sample of the bodily fluid that may be infected, and sending it to a lab where any bacteria present can grow and be identified under a microscope.  A sensitivity is then performed, which means testing the bacteria to determine which antibiotic is most effective against that particular sample. Blood tests can also be used to determine the likelihood of the presence of an infection.  

In some cases, a culture may be obtained and antibiotics started prior to the results of the culture.  This allows treatment to begin promptly, but the choice of antibiotic may change when the results of the culture and sensitivity are obtained.

  So you may be treated with antibiotic A for a few days, then be switched to antibiotic B when the lab determines that antibiotic B would be a more effective choice.

While testing is an important part of antibiotic therapy, it is always better when signs and symptoms of infection are identified early.  The role of the surgery patient is to prevent infection and to be aware of the potential for infection, and to update the surgeon if those signs and symptoms are present.

Antibiotics 101

There are a few rules of thumb when it comes to antibiotics.  First and foremost, if you are given a prescription antibiotic you should finish the prescription.  If you are feeling better, finish the prescription.  If your wound infection appears to have cleared up, finish your prescription.  This is essential to completely eradicating the infection and decreasing the risk of antibiotic resistance. 

Antibiotics have the ability to cause an upset stomach.  Taking them with a meal, when possible, can decrease how upsetting they are to your system.

All antibiotics are not the same.  Some are great for ear infections, others are good for a urinary tract infection, others are used for skin infections.  If your provider determines that you need an antibiotic, know that the antibiotic was selected with care.  The antibiotics that you have sitting in a drawer should not be considered an acceptable substitute.  Remember the first rule, there should not be any leftover antibiotics.

Report serious reactions to antibiotics. Serious reactions range from shortness of breath to serious rashes, severe headache, confusion and skin changes.


Up To Date.  Patient Information: Antibiotics Before Procedures.  Accessed 2014.

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