Prophylactic Antibiotics

Prophylactic antibiotics are antibiotics you take to prevent bacterial infections. Any antibiotics you’d get to treat an infection can be used for prophylaxis. The difference is the timing of when you get the antibiotics.

Antibiotic prophylaxis and antibacterial prophylaxis are other names for using antibiotics this way.

Most of the time, you don’t receive antibiotics until you have symptoms of a bacterial infection or lab results that confirm one. But there are times when it’s better to use antibiotics early to stop an infection from setting in. That’s usually when waiting for symptoms or test results could put you at risk for severe illness or life-threatening complications.

But providers don’t use antibiotics this way in every case. Using antibiotics too often can cause more harm than good. It can lead to antibiotic resistance, increase the risk of side effects and make it easier for other infections to develop, including fungal infections.

Some examples include situations where:

• You have a high risk of getting a bacterial infection, especially a severe one.
• Your body’s natural defenses won’t stop a bacterial infection from happening.
• Getting a bacterial infection is more likely to cause serious complications for you.

Some examples of common antibiotics and ways to use them for prophylaxis include:

• A cephalosporin-class antibiotic, like cefazolin, before surgeries
• A penicillin-class antibiotic, like amoxicillin, before dental procedures
• Nitrofurantoin for preventing urinary tract infections
• A fluoroquinolone-class antibiotic, like levofloxacin, to prevent infections after a transplant

Prophylactic antibiotics aren’t a guarantee that you won’t get sick. But they do make it a lot less likely to happen. And if you do get sick, prophylactic antibiotics can keep the infection from being more severe.

How do prophylactic antibiotics work?

Prophylactic antibiotics prevent bacterial infections before they start. Providers use them when infection risk is high, like before surgery or certain dental procedures, to stop bacteria from entering your body and spreading.

Think of it this way: Your body is a castle. Your skin and immune system act as guards that keep invaders out. Prophylactic antibiotics add extra protection ahead of time, stopping an invasion of the castle (bacteria) before they can cause trouble. They can help with:

• Bigger or deeper wounds: These make it easier for bacteria to enter your body.
• Very deep wounds (including surgeries): Bacteria can get in quickly, sometimes before your body can respond.
• Wound contamination: A large amount of bacteria can overwhelm your body’s defenses.
• Weakened immune system: Your body may not be able to fight off infections as well.
• Repeated bacterial infections: If you have a history of multiple bacterial infections, your body may be at risk for future infections.

What puts you at higher risk for a bacterial infection?

Prophylactic antibiotics use is common in situations where bacterial invaders pose a bigger threat. One example is surgery. Prophylactic antibiotics help your immune system stop any bacteria that try to get in during the surgery. That’s why you might get prophylactic antibiotics right before or during surgery, including dental procedures.

Certain types of injuries are also likely to need prophylactic antibiotics. These are usually more severe injuries or contaminated injuries (meaning something in the injury could be carrying a lot of bacteria with it).

Some examples include:

• Bites (especially from humans and animals like cats)
• Compound fractures
• Penetrating injuries
• Face fractures with contamination, like dirt or debris
• Significant wounds that are contaminated with freshwater or saltwater, or soil
• Injuries that involve parts of your body where bacteria normally live, like your skin, respiratory, digestive and urinary systems

And there are several different medical conditions or reasons that might mean you need antibiotic prophylaxis. Providers might prescribe prophylactic antibiotics to prevent infections or for reasons such as:

• Cellulitis, urinary tract infections and respiratory system infections that keep coming back (antibiotic prophylaxis can stop them from returning)
• Endocarditis or rheumatic heart disease (antibiotics may limit heart damage)
• Whooping cough or bacterial meningitis, which are very dangerous for certain people (prophylactic antibiotics may protect those who face bigger risks from these infections)
• Having a weakened immune system because of diabetes, HIV, chemotherapy or immune system diseases

There are other conditions or reasons why your provider might recommend prophylactic antibiotics. Your provider can tell you more and explain how antibiotics might help.

How to take prophylactic antibiotics

There are three main ways that you can receive prophylactic antibiotics:

• Pill form
• Injection into a muscle (intramuscular) or just under your skin (subcutaneous)
• Intravenous (IV) drip

The form that’s best for you depends on which medication your provider prescribes and why. It’s common for healthcare providers to give you prophylactic antibiotics rather than you getting a prescription for them that you take at home.

How long you take prophylactic antibiotics can also vary widely. Sometimes, you only need a single dose (antibiotic prophylaxis before surgery is an example of this). Other times, you might need to take them in pill form over several days.

Your healthcare provider can tell you more about how you’ll get prophylactic antibiotics. And if you have any questions about how to take them, your provider or a pharmacist can guide you.