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Amoxicillin/clavulanate Patient Tips

Medically reviewed by C. Fookes, BPharm. Last updated on Nov 15, 2017.

How it works

  • Amoxicillin/clavulanate is 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.
  • Amoxicillin/clavulanate belongs to the group of medicines known as penicillins.


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


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 are the most common side effects reported.
  • May cause overgrowth of a yeast, candida, causing thrush (a yeast infection in the mouth) or vaginal yeast infections.
  • Amoxicillin/clavulanate should not be used if 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 Amoxicillin/clavulanate may not be interchangeable, for example:
  • The 250mg and 500mg tablet of the brand of amoxicillin/clavulanate called Augmentin both contain 125mg of clavulanate potassium; therefore two 250mg tablets should not be substituted for one 500mg tablet
  • .
  • The 250mg tablet of Augmentin contains 125mg 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 amoxicillin/clavulanate may need reducing in very severe renal impairment.
  • Severe diarrhea associated with Clostridium difficile is a potential side effect of almost all antibacterial agents, including amoxicillin/clavulanate.
  • May not be suitable for some people including those with a previous history of hepatic dysfunction associated with amoxicillin/clavulanate, allergic to penicillin or cephalosporins, with mononucleosis, or with an infection caused by bacteria that are not susceptible to amoxicillin/clavulanate.
  • May interact with some other medications including probenecid, allopurinol, oral contraceptives, oral anticoagulants, and some urinary glucose tests.

Notes: 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. For a complete list of all side effects, click here.

Bottom Line

Amoxicillin/clavulanate 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.


  • Take at the start of a light meal to improve the absorption of clavulanate potassium and to minimize the potential for gastrointestinal intolerance.
  • Some bacteria are inherently resistant to amoxicillin/clavulanate whereas others can acquire resistance. To help prevent resistance and treatment failure, be sure to complete the full course of antibiotic, even if you feel better.
  • Do not take 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; a swelling of the face, lips, or throat; difficulty breathing; or a tightness in the chest.
  • Amoxicillin/clavulanate 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 amoxicillin/clavulanate use.
  • See your doctor if you develop prolonged or significant diarrhea while taking amoxicillin/clavulanate 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 reduced or eliminated discoloration.
  • Phenylketonurics should avoid Augmentin chewable tablets and Augmentin powder for oral solution (Augmentin is a brand of amoxicillin/clavulanate) because these products contain aspartame (contains phenylalanine).

Response and Effectiveness

  • Peak concentrations are usually seen within 1.5 hours of a dose of amoxicillin/clavulanate; 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 amoxicillin/clavulanate whereas others can acquire resistance. To help prevent resistance and treatment failure, be sure to complete the full course of antibiotic, even if you feel better.


Amoxicillin and clavulanate potassium [Package Insert]. Revised 09/2017. Micro Labs Limited

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

Copyright 1996-2018 Revision Date: 2017-11-15 00:57:22

Further information

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