What are the side effects of amoxycillin with clavulanic acid?

It is important to tell your health professional about any medicines you may be taking, or if you have any current illness, allergies or long-term health conditions. This will help them decide if amoxycillin with clavulanic acid is suitable for you.

If you have ever had an allergic reaction with symptoms such as hives, fever, breathing problems or anaphylactic shock when taking amoxycillin with clavulanic acid or any other antibiotic in the past, you must tell your doctor.

Side effects of amoxycillin, clavulanic acid and other antibiotics from the penicillin family

(1 to 10 in 100 people)
(fewer than 1 in 100 people)
(fewer than 1 in 1000 people at high doses)
Rash (see below)
Temporary changes in liver function
Clostridium difficile infection
Nerve problems (e.g. drowsiness, hallucinations, coma, seizures)
Unusual bleeding
Low blood cell counts (neutropenia, thrombocytopenia)
Liver problems (cholestatic hepatitis; see below)
Note: this is not a complete list of all the possible side effects of amoxycillin with clavulanic acid.


A red rash with bumps (maculopapular rash) covering large parts of the body is common with amoxycillin if you have been taking it for more than 7 days. The rash usually clears within 7 days of stopping amoxycillin. If you continue taking amoxycillin, the rash will take 6 to 14 days to clear.

Liver problems (cholestatic hepatitis)

Amoxycillin with clavulanic acid can cause a liver problem called cholestatic hepatitis, but this is rare (fewer than 1 in 1000 people will experience the side effect). This affects how your liver works but it is reversible. It can start while you are taking amoxycillin with clavulanic acid, or a few weeks after you have stopped taking it, and can last for 5 to 6 weeks. The risk of cholestatic hepatitis increases if you are 55 years or older, male, and if you take amoxycillin with clavulanic acid for more than 14 days.

Allergic reactions to amoxycillin, clavulanic acid or other penicillin antibiotics

Some people experience an allergic reaction to amoxycillin with clavulanic acid or other antibiotics from the penicillin family. This is due to an over-reaction of their immune system to the antibiotic.

Symptoms of an allergic reaction can include:

  • hives (large, red raised areas on the skin)
  • swollen lips or mouth
  • fever (a temperature of 38.5°C or higher)
  • breathing problems
  • fainting.

Seek medical advice if you experience any of these symptoms while you are taking amoxycillin.

It is not known why this happens to some people and not others, but it may mean that you will have to avoid taking amoxycillin and any penicillin-related antibiotic in the future. There are other types of antibiotics which don’t cause this reaction that will be suitable for you.

Read more about the common side effects of antibiotics.

Who can I ask about side effects?

If you’re concerned that you or someone in your care may have had side effects related to a medicine, seek medical advice. People with questions about their medicines or seeking general information about side effects can also call the NPS Medicines Line on 1300 633 424 (Monday-Friday, 9am-5pm AEST). To report possible side effects call the Adverse Medicine Events (AME) line on 1300 134 237 from anywhere in Australia (Monday–Friday, 9am–5pm AEST).

  • Rossi S, ed. Australian Medicines Handbook [online]. Adelaide: AMH, July 2012.
  • Sweetman S, ed. Martindale: The complete drug reference [online]. London: Pharmaceutical Press (accessed 18 October 2011).
  • Antibiotic Expert Group. Therapeutic Guidelines: Amoxycillin plus clavulanate. Melbourne: Therapeutic Guidelines Limited, 2012 (accessed 24 February2012).