Sounds like 'CEF-a-klor'

Easy-to-read medicine information about cefaclor – what it is, how to take cefaclor safely and possible side effects.

Type of medicine Also called
  • Antibiotic (to treat infections)
  • Ranbaxy-Cefaclor®

What is cefaclor?

Cefaclor is an antibiotic used to treat infections caused by bacteria, such as infections of the urinary tract, skin or chest. It works by killing or stopping the growth of bacteria (bugs) and gets rid of the infection. Cefaclor does not work against infections caused by viruses. In New Zealand, cefaclor is available as capsules and liquid.


  • The usual dose of cefaclor in adults is 1 capsule (250 mg) 3 times a day.
  • The dose for children will depend on their body weight; it is usually given 3 times a day.
  • Your doctor will advise you how long to take cefaclor for (usually 5 to 7 days, but can be up to 10 days).
  • Always take your cefaclor exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much cefaclor to take, how often to take it, and any special instructions.

 How to take cefaclor

  • Capsule: swallow your capsule with a glass of water.
  • Liquid: shake the medicine well. Measure the right amount using an oral syringe or medicine spoon. You can get these from your pharmacy. Do not use a kitchen spoon as it will not give you the right amount. Read more: tips on how to give medicines to babies and children.
  • Cefaclor is usually given 3 times a day. Try to space the doses evenly throughout the day such as the first thing in the morning, early afternoon and at bedtime. Ideally, these times should be at least 4 hours apart. 
  • You can take cefaclor with or without food.
  • If you forget to take your dose at the correct time, take one as soon as you remember. Try to take the correct number of doses each day, leaving at least 4 hours between doses. Do not take two doses at the same time to make up for a forgotten dose.
  • It is important to take the whole course of antibiotics for the number of days your doctor has told you to. Do not stop taking it, even if you feel your infection has cleared up.
  • You should start to get better after taking cefaclor for a few days. If you do not feel better or get more unwell, contact your doctor.

Precautions – before starting cefaclor

  • Have you ever had an allergic reaction to a medicine, especially a penicillin antibiotic?
  • Are you pregnant or breastfeeding?
  • Are taking any other medicines? This includes any medicines you are taking which you can buy without a prescription, as well as herbal and complementary medicines.

If so, it’s important that you tell your doctor or pharmacist before you start cefaclor. Sometimes a medicine isn’t suitable for a person with certain conditions, or it can only be used with extra care.

Precautions – while taking cefaclor

  • Store your cefaclor capsules in a cool, dry place, away from direct heat and light.
  • If you have been given liquid medicine, this will have been made up by the pharmacy and you may need to keep it in the fridge – check the instructions on the bottle. Make sure the medicine does not freeze.
  • If your child is sick (vomits) and it is less than 30 minutes after having a dose of cefaclor, give them the same dose again. But, if your child is sick (vomits) and it is more than 30 minutes after having a dose of cefaclor, you do not need to give them another dose. Wait until the next dose is due.
  • If you are taking the contraceptive pill, the effectiveness of the pill can be reduced if you are sick (vomiting) or have diarrhoea which lasts for more than 24 hours. If this happens, ask your doctor or pharmacist for advice about contraception over the next few days.

Possible side effects

Like all medicines, cefaclor can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.

Side effects What should I do?
  • Feeling sick (nausea) or vomiting
  • Dizziness, headache
  • Try taking cefaclor with food.
  • Tell your doctor if troublesome
  • Diarrhoea (runny poos)
  • This may settle after a few days.
  • Tell your doctor if troublesome.
  • Vaginal itching, soreness or discharge (thrush)
  • Ask your doctor or pharmacist for advice.
  • Signs of allergic reaction such as skin rash, itching, swelling of the lips, face, and mouth or difficulty breathing
  • Tell your doctor immediately or ring HealthLine 0800 611 116


Cefaclor interacts with a few important medications or herbal supplements, so check with your doctor or pharmacist before starting cefaclor. 

Learn more

cefaclor New Zealand Formulary Patient Information


  1. Cefaclor New Zealand Formulary
  2. Antibiotics: choices for common infections BPAC, 2017
Credits: Sandra Ponen, Pharmacist. Reviewed By: Angela Lambie, Pharmacist, Auckland Last reviewed: 30 Nov 2018