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Amoxicillin vs Augmentin: What’s the Difference?
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When To Use Augmentin Instead
When the bacteria causing an infection is suspected or confirmed to produce a beta-lactamase that inactivates amoxicillin, it’s important to select an antibiotic that will effectively treat the infection. Situations like this are when to use Augmentin. Some pneumonias, ear infections, or sinus infections can be caused by bacteria that are resistant to amoxicillin. Sometimes, this resistance is suspected because of population-level data about the rate of resistant bacteria in a certain cohort. In other situations, a sample is taken to a lab to determine what bacteria is present. That bacteria can then be tested against different antibiotics to determine which ones will effectively treat it. (6, 7)
Augmentin Side Effects vs Amoxicillin Side Effects
Both amoxicillin-clavulanate and amoxicillin can cause side effects. The specific side effects are different when comparing amoxicillin vs Augmentin, but one of the big differences is the risk of gastrointestinal (GI) side effects. These GI side effects are thought to be related to the disruption of the gut microbiome. We all have bacteria that live in our intestines, and a healthy balance of those bacteria can help prevent diarrhea. Antibiotics kill the bad bacteria they’re being used to treat, but they can also kill the good bacteria that live in the gut. When the microbiome is out of balance, people can have GI side effects. (8)
Augmentin (amoxicillin-clavulanate) is more likely to cause GI issues than amoxicillin. Depending on the study, anywhere from 3% to 34% of people who take Augmentin may experience diarrhea. With amoxicillin, between 1% and 10% of people will experience one of those three GI side effects (diarrhea, nausea, or vomiting). (5, 6)
The diarrhea caused by antibiotics is called antibiotic associated diarrhea (AAD). Diarrhea is more common with amoxicillin-clavulanate vs amoxicillin. Taking higher doses and being on the medication for a longer period of time are both risk factors for antibiotic associated diarrhea. The good news is that most AAD resolves on its own! If you’re experiencing diarrhea that isn’t going away or is causing dehydration, it’s a good idea to reach out to your healthcare provider to be sure there isn’t something else going on. (9, 10)
If you’re experiencing diarrhea on a GLP-1 medication and your doctor prescribes you an antibiotic for an infection, you may be worried about the antibiotic making your diarrhea worse. Augmentin is more likely to cause diarrhea than amoxicillin, but many different antibiotics can cause diarrhea. If you’re worried about side effects of your GLP-1 medication overlapping with side effects of your antibiotic, check in with your healthcare provider for advice.
FAQs
Is Augmentin stronger than amoxicillin?
Augmentin is often considered a stronger antibiotic than amoxicillin. This is because Augmentin is amoxicillin plus an additional ingredient to overcome bacterial resistance.
Can you switch between amoxicillin vs Augmentin?
In some cases, you may switch antibiotics, yes. Your provider may switch you from amoxicillin to Augmentin if they learn the bacteria causing your infection is resistant to amoxicillin alone, for example.
Can you take Augmentin if you’re allergic to amoxicillin?
No. Augmentin is the brand name for amoxicillin-clavulanate. If you are allergic to amoxicillin, you should not take Augmentin.
How do you know when to use Augmentin vs amoxicillin?
Augmentin and amoxicillin are both prescription-only medications, and your provider will take into consideration where your infection is, what type of bacteria may be causing it, any prior antibiotic use, and other factors.
What does Augmentin vs amoxicillin treat?
Augmentin treats bacteria that may be resistant to amoxicillin, and can be used for more severe infections.
Disclaimer: This article is for educational purposes only and should not be considered medical advice. The information provided does not constitute recommendations for treatment. Always consult with your healthcare provider about your specific situation, symptoms, and treatment options.
References
Ashford, W. A., Golash, R. G., & Hemming, V. G. (1976). Penicillinase-producing Neisseria gonorrhoeae. Lancet (London, England), 2(7987), 657–658. https://doi.org/10.1016/s0140-6736(76)92467-3.
Lobanovska, M., & Pilla, G. (2017). Penicillin's Discovery and Antibiotic Resistance: Lessons for the Future?. The Yale journal of biology and medicine, 90(1), 135–145.
Bush, K., & Bradford, P. A. (2020). Epidemiology of β-Lactamase-Producing Pathogens. Clinical microbiology reviews, 33(2), e00047-19. https://doi.org/10.1128/CMR.00047-19
Huttner, A., Harbarth, S., Carlet, J., Cosgrove, S., Goossens, H., Holmes, A., Jarlier, V., Voss, A., & Pittet, D. (2013). Antimicrobial resistance: a global view from the 2013 World Healthcare-Associated Infections Forum. Antimicrobial resistance and infection control, 2, 31. https://doi.org/10.1186/2047-2994-2-31
UpToDate Lexidrug. (2025). Amoxicillin: Drug information. UpToDate. Retrieved April 13, 2026, from https://www.uptodate.com/contents/amoxicillin-drug-information
UpToDate Lexidrug. (2025). Amoxicillin and clavulanate: Drug information. UpToDate. Retrieved April 13, 2026, from https://www.uptodate.com/contents/amoxicillin-and-clavulanate-drug-information
Bayot, M. L. (2024, May 27). Antimicrobial susceptibility testing. StatPearls [Internet]. https://www.ncbi.nlm.nih.gov/books/NBK539714/
Gu, X., Sim, J. X. Y., Lee, W. L., Cui, L., Chan, Y. F. Z., Chang, E. D., Teh, Y. E., Zhang, A. N., Armas, F., Chandra, F., Chen, H., Zhao, S., Lee, Z., Thompson, J. R., Ooi, E. E., Low, J. G., Alm, E. J., & Kalimuddin, S. (2021). Gut Ruminococcaceae levels at baseline correlate with risk of antibiotic-associated diarrhea. iScience, 25(1), 103644. https://doi.org/10.1016/j.isci.2021.103644)
Litao G, Jingjing S, Yu L, Lei Z, Xiaona H, Zhijing Z. Risk factors for antibiotic-associated diarrhea in critically ill patients. Med Sci Monit. 2018;24:5000-5007. doi:10.12659/MSM.911308 [PubMed 30020891]
Gillies, M., Ranakusuma, A., Hoffmann, T., Thorning, S., McGuire, T., Glasziou, P., & Del Mar, C. (2015). Common harms from amoxicillin: a systematic review and meta-analysis of randomized placebo-controlled trials for any indication. CMAJ: Canadian Medical Association Journal, 187(1), E21–E31. https://doi.org/10.1503/cmaj.140848
Augmentin vs. Amoxicillin for Skin Infection and Ear Infection: Important Differences and Potential Risks. (2025). GoodRx. https://www.goodrx.com/compare/augmentin-vs-amoxicillin
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