Can antibiotics make you feel tired?

Reviewed by:
Angela DiLaura, NP
Clinical Informatics and Quality Manager
Last updated on December 12, 2021

If you’ve been prescribed a round of antibiotics, you might be thinking, “Whoa, hang on! Will these make me sleepy?”

And that’s a reasonable concern — it’s possible.

But don’t second-guess your prescription just yet. Your particular antibiotic might have the exact opposite effect — more energy! And even if not, there may be things you can do to counteract feelings of fatigue.

Keep reading, and let’s find out everything we need to know about how and why antibiotics could make you tired.

A refresher on what antibiotics are

Antibiotics are medicines used to treat bacterial infections—and only bacterial infections. We’re talking about things like:

Antibiotics are not used to treat viral infections and have no effect on them whatsoever. If you have the flu, or a cold, COVID, or anything else like that, don’t go looking for antibiotics — your doctor won’t prescribe them and they won’t work.

In fact, it’s dangerous to take antibiotics when you don’t need them. Overuse can lead to antibiotic resistance, a phenomenon that makes antibiotics less effective over time.

Common side effects

We’re here to talk about sleepiness, but it’s actually more likely that you’ll encounter one of these side effects instead:

  • Rash.
  • Nausea.
  • Diarrhea.
  • Yeast infection.

Rare and dangerous side effects

These are less likely, but still important to be aware of:

  • Severe, even life-threatening, allergic reactions.
  • C. difficile infection, which causes severe diarrhea and can lead to hospitalization and death.
  • Infections from antibiotic resistant bacteria.

Don’t worry about these, but do be aware and consult with your doctor when taking any antibiotic.

Why do antibiotic side effects happen in the first place?

It isn’t very pleasant to think about dealing with any of these issues on top of what’s ailing you. 

However, the symptoms listed above are often a sign that your antibiotics are working. 

That’s because antibiotics decrease the overall number of bacteria in your body—including the good kind—which can, for example, upset your stomach or allow for greater production of yeast.

Which antibiotics are most likely to make you feel tired?

This is a bit of a trick question.

Most likely, it’s not the antibiotic that makes you feel drowsy, but the infection that you’re taking the antibiotic for.

There’s nothing in antibiotics that’s been shown to have a cause-and-effect relationship with drowsiness. But if your body is fighting an infection, it’s natural that you’d feel tired. 

That feeling is, in essence, your body trying to get you to temporarily shut down certain functions—active thinking, physical movement, etc.—so it can focus its energy on healing itself.

What to do if antibiotics make you tired

Easy: sleep.

Your body wants to slow down so it can focus on fighting an infection. Listen to your body and take a nap.

But — we get it — it’s not always that simple. People lead busy lives and often it’s not possible to just stop what you’re doing. So, here are some suggestions on ways to lessen your drowsiness or work around it:

  • Prioritize sleep while you’re sick. Now maybe isn’t the best time to start a new exercise routine, for instance.

  • Wait to see how the medication affects you before engaging in any attention-heavy tasks like driving.

  • Avoid taking over-the-counter or recreational drugs, as well as alcohol. Depressants—like alcohol—can cause additional drowsiness, as can some OTC drugs.

Be aware of possible interactions with antibiotics

Always consult with your doctor when taking antibiotics and always be transparent about what other medications — prescription or over-the-counter — you’re taking.

Some antibiotics can interact with certain drugs and behave differently than expected. Here are a few things to watch out for.


It’s not likely that alcohol will directly interact with most antibiotics. But as we mentioned above, you may feel tired when you’re sick, your antibiotics could upset your stomach — and both those symptoms could be heightened if you drink alcohol.

Other medications and antibiotics

There are a lot of different types of antibiotics, each with their own unique potential for drug interactions. For example, tetracyclines, which are often used to treat skin infections, can interact with everything from vitamins to antacids.

Your HealthTap doctor can prescribe the right antibiotics for you

The advantage of having an ongoing relationship with a HealthTap primary care doctor is that they get to know you and your unique health needs.

Tell your online doctor everything — all the medications you’re taking, all the over-the-counter drugs you use, and any other health concerns you have — and they’ll take that into account when prescribing antibiotics and other medicine.

If you have any follow-up questions after an appointment, you can text them to your doctor for free.

Get in touch with your HealthTap doctor today, and get the answers you need about how an antibiotic might affect you. 

HealthTap Editors

HealthTap Editors

HealthTap articles are reviewed by MDs, PhDs, NPs, nutritionists and other healthcare professionals. Visit to learn more and meet some of the medical editorial board members behind our blog. The information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment. HealthTap is a virtual-first, affordable urgent- and primary-care clinic, providing top-quality physician care nationwide to Americans with or without insurance. Our proprietary, easy-to-use, and innovative apps and electronic medical record apply Silicon Valley standards to effectively engage consumers and doctors online to increase the equity, accessibility, and efficiency of ongoing medical care for consumers, providers, employers, and payers. In addition, with HealthTap, businesses can offer virtual primary care to employees for less than the cost of free coffee. HealthTap's US-based board-certified physicians are available throughout North America. For more information, visit

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