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Augmentin: 7 things you should know

Medically reviewed by Carmen Fookes, BPharm. Last updated on Oct 12, 2022.

1. How it works

  • Augmentin is a brand (trade) name for a penicillin-type combination antibiotic made up of amoxicillin (the active, antibiotic part) and clavulanate potassium (boosts the effectiveness of the amoxicillin).
  • Amoxicillin kills bacteria by inhibiting the synthesis of cell wall mucopeptides (crystal lattice-like structures composed of amino acids). This weakens and destroys the bacterial cell wall. Amoxicillin has a similar action to ampicillin.
  • Clavulanate potassium protects amoxicillin from inactivation by beta-lactamases by binding strongly to beta-lactamases near their active site. By itself, clavulanate potassium only has weak antibacterial activity, but when used together with amoxicillin, it extends its spectrum so that it may be used to treat infections caused by beta-lactamase-producing organisms.
  • Augmentin belongs to the class of medicines known as penicillins.

2. Upsides

  • Effective against more organisms than amoxicillin by itself.
  • Used to treat infections of the airways, ears, sinuses, skin, and urinary tract that have been caused by susceptible bacteria, such as:
  • beta‑lactamase-producing isolates of Haemophilus influenzae
  • Moraxella catarrhalis
  • Staphylococcus aureus
  • Escherichia coli
  • Klebsiella species
  • Enterobacter species.
  • Available as a tablet and chewable tablet and in extended-release and liquid formulations.
  • Augmentin is available as generic amoxicillin/clavulanate potassium.

3. Downsides

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

  • Diarrhea or loose stools, nausea, skin rashes or itching, and vomiting
  • Can cause an overgrowth of the yeast, Candida, causing thrush (a yeast infection in the mouth) or vaginal yeast infections
  • Augmentin should not be used if the susceptibility results show susceptibility to amoxicillin, indicating that the infectious bacteria are not producing beta-lactamase. Amoxicillin should be used instead
  • May cause an allergic reaction in those allergic to penicillin or cephalosporins
  • Different formulations and strengths of Augmentin may not be interchangeable, for example:
  • The 250mg and 500mg tablets of Augmentin both contain 125mg of clavulanate potassium; therefore two 250mg tablets are not equivalent to one 500mg tablet
  • The 250mg tablet of Augmentin contains 125mg of clavulanate potassium and the 250mg chewable tablet contains 62.5mg of clavulanate potassium; therefore the tablet should not be substituted for the chewable tablet and vice-versa.
  • The dosage of Augmentin may need to be reduced in people with very severe renal impairment
  • Severe diarrhea associated with Clostridium difficile is a potential side effect of almost all antibacterial agents, including Augmentin
  • May not be suitable for some people including those with a previous history of hepatic dysfunction associated with Augmentin, allergic to penicillin or cephalosporins, with mononucleosis, or with an infection caused by bacteria that are not susceptible to Augmentin
  • May interact with some other medications including probenecid, allopurinol, oral contraceptives, oral anticoagulants, and some urine glucose tests.

Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects

4. Bottom Line

Augmentin is a combination penicillin-type antibiotic that should be reserved for the treatment of infections caused by susceptible beta-lactamase-producing bacteria. Its use may be limited by resistance and side effects such as diarrhea and yeast overgrowth.

5. Tips

  • Take Augmentin at the start of a light meal to improve the absorption of clavulanate potassium and to minimize the potential for gastrointestinal intolerance.
  • Take exactly as directed by your doctor and complete the course as prescribed to reduce the risk of bacterial resistance developing.
  • Do not take it if you are allergic to penicillin or any other penicillin-like antibiotic such as ampicillin, dicloxacillin, oxacillin, or others.
  • Call for emergency help if you experience any allergic-type reactions including a rash; swelling of the face, lips, or throat; difficulty breathing; or a tightness in the chest.
  • Augmentin may encourage the overgrowth of yeasts, such as Candida. This may be seen as oral or vaginal thrush. See your doctor if you suspect you have developed thrush as a result of Augmentin use.
  • See your doctor if you develop prolonged or significant diarrhea while taking Augmentin or within several months of finishing the course.
  • May cause tooth discoloration (brown, yellow, or gray staining); the risk is higher in pediatric patients. Brushing or professional dental cleaning reduces or eliminates discoloration.
  • Phenylketonurics should avoid Augmentin chewable tablets and Augmentin powder for oral solution which both contain aspartame (this contains phenylalanine).

6. Response and effectiveness

  • Peak concentrations are usually seen within 1.5 hours of a dose of Augmentin; however, it may take up to 48 hours of dosing for a clinical improvement to be seen.
  • Effective against more organisms than amoxicillin by itself.
  • Some bacteria are inherently resistant to Augmentin whereas others can acquire resistance. To help prevent resistance and treatment failure, be sure to complete the full course of the antibiotic, even if you feel better.

7. Interactions

Medicines that interact with Augmentin may either decrease its effect, affect how long it works, increase side effects, or have less of an effect when taken with Augmentin. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Common medications that may interact with Augmentin include:

  • allopurinol (may increase the incidence of rash)
  • anticoagulants (blood thinners), such as warfarin (may prolong bleeding time)
  • oral contraceptives (may decrease absorption leading to reduced efficacy)
  • probenecid (may increase blood concentrations of amoxicillin).

Augmentin may cause a false-positive reaction for glucose in the urine with copper reduction tests (eg, Benedict's or Fehling's solution), but not with enzyme-based tests.

Note that this list is not all-inclusive and includes only common medications that may interact with Augmentin. You should refer to the prescribing information for Augmentin for a complete list of interactions.


Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Augmentin only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Copyright 1996-2023 Revision date: October 12, 2022.