Antibiotics for Flu: Here’s Why Antibiotics Don’t Work

Antibiotics are one of the most popular types of infection-fighting drugs out there. But it turns out that we use them more often than needed. According to the Centers for Disease Control and Prevention (CDC), 1 in every 3 antibiotic prescriptions is unnecessary.

That’s why it’s important to know which types of infections antibiotics can or can’t treat. And the flu is one of the conditions that antibiotics don’t work against. Let’s learn exactly why.

What is the flu, and what kind of infection is it?

Infections can be caused by different types of germs, including viruses, bacteria, parasites, and fungi. The infection we call “the flu” is formally known as influenza. It’s caused by a virus of the same name — the influenza virus — which means the flu is a viral infection.

Here are some other viral infections you might recognize:

• COVID-19
• The common cold
• Herpes
• HIV
• Chickenpox
• Shingles

What kinds of infections do antibiotics treat?

To understand what antibiotics are, let’s quickly break the word down into its Latin and Greek origins:

• “Anti-” means against
• “Bio-” means life

So antibiotics are medications that oppose the life of certain types of germs. But not all germs. Antibiotics actually only work against bacteria — not parasites, fungi, or viruses. And since the flu is caused by a virus, antibiotics don’t treat the flu. Instead, they treat infections caused by bacteria like:

• Strep throat
• Whooping cough
• Tuberculosis
• Anthrax
• Bacterial pneumonia

If you have a bacterial infection that requires treatment, your healthcare provider might prescribe antibiotics such as:

• Amoxicillin with clavulanate (Augmentin)
• Cephalexin (Keflex)
• Sulfamethoxazole with trimethoprim (Bactrim)
• Metronidazole (Flagyl)

But none of these popular antibiotics, or any others, are suitable for flu treatment. In fact, using antibiotics when you don’t need them can make them less effective for you later on. If you actually do need the medication, it may not work as well as it should because of antibiotic resistance. Plus, like all drugs, antibiotics can cause side effects. Taking them when you don’t need them puts you at risk for side effects unnecessarily.

How do you treat the flu?

Antivirals treat the flu — specifically, a class of antivirals called neuraminidase inhibitors:

• Oseltamivir (Tamiflu)
• Zanamivir (Relenza)
• Peramivir (Rapivab)
• Baloxavir marboxil (Xofluza)

These drugs work by blocking the neuraminidase protein in flu viruses. This prevents the virus from being able to copy itself, spread to healthy cells, and cause widespread infection throughout the body. While you may still experience symptoms, taking one of these medications can make symptoms milder and speed up your recovery time.

What to do if you think you may have the flu

This year especially, it’s important to get a flu vaccine. Since the COVID-19 pandemic is ongoing, you want to keep your immune system as healthy as possible. If you think you might have the flu:

• Stay away from others as much as possible.
• Visit a healthcare provider for testing.
• Take any antivirals you’re prescribed as instructed.

If you are diagnosed with the flu, your healthcare provider may or may not prescribe antivirals. Here are a few other ways you can manage your flu symptoms:

• Get lots of rest: Many people who get the flu feel extremely tired. Get as much rest as possible to help your body recover.
• Drink lots of fluids: Keeping your body hydrated can help your immune system stay strong and fight off the flu more effectively.
• Consider over-the-counter medications to manage your symptoms: If your symptoms are bothersome, you might consider over-the-counter (OTC) medications to help. If you have chronic conditions, always check with your healthcare provider before taking any OTC meds.
• For fever, body aches, or a sore throat: acetaminophen (Tylenol), ibuprofen (Advil, Motrin), naproxen (Aleve)
• For a runny nose: decongestant medications such as pseudoephedrine (Sudafed)
• For a cough with mucus: guaifenesin (Mucinex)
• For a dry cough: dextromethorphan (Delsym)

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Curtseyed of Megan N. Brown, PharmD, RPh