skip to Main Content

Facts About Antibiotics

Child receiving medicine via syringe
Antibiotics are very common medications prescribed for a variety of bacterial infections. Most people have been on an antibiotic at least once as a child or an adult. Because of this, poison centers across the country handle thousands of calls every year about antibiotics.


Bottle of Antibiotics

The short answer is “no” antibiotics do not treat viral infections. Antibiotics only treat bacterial infections. Some common bacterial infections include strep throat, urinary tract infections, and pneumonia. These conditions most likely need treatment with an antibiotic. Some illnesses such as sinus infections, ear infections, and bronchitis can be caused by either a bacteria OR a virus, so it is important to discuss the appropriate treatment with a physician. Often, antibiotics are NOT needed for those illnesses. Other infections are caused only by viruses, such as the common cold, sore throat, COVID-19 and norovirus – remember, antibiotics will not help treat these conditions. There are some viral infections, such as COVID-19 and influenza, that may benefit from an antiviral medication. These medicines are different than antibiotics and some are only available in an IV formulation. The most common oral prescription antiviral medication used to treat influenza is called Tamiflu® (oseltamivir).


Antibiotics differ in how they work and the bacteria they treat. There are over 100 antibiotics approved by the FDA but here are some of the common classes prescribed:

– Penicillins: penicillin, amoxicillin

– Cephalosporins: cefdinir, cefalexin

– Tetracyclines: doxycycline

– Macrolides: azithromycin, clarithromycin

– Quinolones: ciprofloxacin, levofloxacin

– Others: clindamycin, trimethoprim & sulfamethoxazole, nitrofurantoin, metronidazole

What are side effects of antibiotics?

With so many variations in the way they work in the body, antibiotic side effects differ based on the type and dose of the medication. Most antibiotics are well-tolerated with only minor side effects. The most common side effects are poor appetite, upset stomach, and diarrhea. Some people may be allergic to certain antibiotics. If someone has hives and develops any difficulty breathing or wheezing, call 911 immediately!

can you overdose on antibiotics?

Even in large amounts, ingesting more antibiotics than the normal dose typically does not result in serious symptoms…but we need more details to fully answer this question. For example, the Missouri Poison Center is often called after a toddler drinks from their bottle of antibiotics. If they like the taste, parents may find their child “dosing themselves”. When a large amount is ingested, the same minor symptoms above are expected, but may be more noticeable. Other poison center calls are about someone who intentionally swallowed a large amount of antibiotics to harm themselves. This can be more dangerous and requires evaluation in an emergency room. If you or someone you know is depressed or intentionally taking more medicines, be sure to reach out for help.

what is antibiotic resistance?

Child receiving medicine via syringe

Bacteria are living things and can figure out ways to “out-smart” the antibiotic. Antibiotics may not work as well if we do not use them correctly. Situations that increase antibiotic resistance include: taking antibiotics when they are not needed, “saving” antibiotics for later, not completing the prescribed course of therapy (stopping the antibiotic early), and/or taking antibiotics that were prescribed for someone else. This can make infections more difficult to treat leading to more expensive hospital stays and worse outcomes for patients. That is why it is always important to use antibiotics responsibly according the advice of your physician. Always take them as prescribed and continue the treatment for the full course of therapy, even if you feel better before it is complete. Read more at the Centers for Disease Control (CDC) website:

For any questions or concerns about antibiotics, call the Poison Help line at 1-800-222-1222. Specially trained nurses and pharmacists are available 24/7/365 to answer your questions. The service is free and confidential.

Call Now