What are the side effects of cefaclor?

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 cefaclor 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 cefaclor any other antibiotic in the past (e.g. amoxycillin), you must tell your doctor.

If you have kidney, liver, or severe bowel problems you must tell your doctor.

Side effects of cefaclor and related antibiotics (cephalosporins)

(1 to 10 in 100 people)
(fewer than 1 in 100 people)
(fewer than 1 in 1000 people at high doses)
Nausea or vomiting
Headache and dizziness
Allergic reactions
Thrush (candida infection)
Clostridium difficile infection
Serum sickness-like syndrome (see below) Problems with liver function
Nerve problems (confusion, seizures)
Low blood cell counts (neutropenia and thrombocytopenia)
Note: this is not a complete list of all the possible side effects of cefaclor.

Serum sickness-like syndrome

Serum sickness-like syndrome is a side effect that occurs more often in children than in adults, but is uncommon. Symptoms include skin rashes, swollen glands and pain and swelling in the joints. The symptoms last for 6 to 12 days, and will clear up after stopping cefaclor.

Read more about the common side effects of antibiotics.

Antibiotics and allergic reactions

Some people experience an allergic reaction to cefaclor or other antibiotics. 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, tongue, 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 an antibiotic.

It is not known why this happens to some people and not others, but it may mean that you will not be able to take the 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: Cefaclor. Melbourne: Therapeutic Guidelines Limited, 2012 (accessed 27 March 2012).