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Cefaclor for infection


Before you take cefaclor, make sure your doctor knows if you have ever had an allergic reaction to any other antibiotic.

Space your doses out evenly over the day and complete the full course of the antibiotic, even if you feel your infection has cleared up.

The most common side-effect is diarrhoea, which is usually mild and soon passes. If it becomes severe or lasts for more than 24 hours, you should speak with your doctor.

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About cefaclor

Type of medicine

A cephalosporin antibiotic

Used for


Also called


Available as

Capsules, modified-release tablets and oral liquid medicine

Cefaclor is a broad-spectrum antibiotic, which means that it is active against a wide variety of bacteria. It is used to treat bacterial infections such as urinary tract infections, skin infections, chest infections, ear infections and sinusitis. It is suitable for adults and children, and can be taken during pregnancy. Some people who are allergic to penicillin antibiotics may not be able to take cefaclor, so make sure your doctor knows if you have ever had an allergic reaction to any other antibiotic.

Cefaclor treats an infection by killing the bacteria that are causing it.

Before taking cefaclor

Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking cefaclor it is important that your doctor knows:

  • If you have ever had an allergic reaction to a medicine. It is particularly important that you tell your doctor if you have had a bad reaction to a penicillin or cephalosporin antibiotic.

  • If you are pregnant, trying for a baby or breastfeeding. (Although cefaclor is not known to be harmful to babies, it is still important that you tell your doctor if you are expecting or breastfeeding a baby.)

  • If you are taking or using any other medicines. This includes any medicines you are taking which are available to buy without a prescription, such as herbal and complementary medicines.

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How to take cefaclor

  • Before you start taking cefaclor, read the manufacturer's printed information leaflet from inside your pack. The manufacturer's leaflet will give you more information about the antibiotic and a full list of side-effects which you may experience from taking it.

  • If you are taking capsules or liquid medicine, the usual dose for an adult is 250-500 mg three times daily. For a child, the usual dose is 62.5-250 mg three times daily, depending upon age. Your doctor will tell you what dose is right for you (or your child) and this information will be printed on the label of the pack to remind you. Your course of treatment may be for longer or shorter periods of time than mentioned here, so it is important that you take cefaclor exactly as your doctor tells you to. If you have been given liquid medicine, read the directions carefully to make sure you measure out the correct amount of medicine. Cefaclor capsules and liquid medicine can be taken either before or after food, although they may start to work sooner if they are taken before food.

  • If you are taking cefaclor modified-release tablets (for example, Distaclor MR®), you will be prescribed one or two tablets to take twice daily. Take the tablets with meals and swallow the tablets whole - do not chew or break them.

  • Space your doses out evenly throughout the day. Keep taking the antibiotic until the course is finished unless you are told to stop. Taking the full course is important (even if you feel your infection has cleared up) in order to prevent the infection from coming back.

  • If you forget to take a dose, take one as soon as you remember. Try to take the correct number of doses each day, but do not take two doses at the same time to make up.

Getting the most from your treatment

  • Some people develop thrush (redness and itching in the mouth or vagina) after taking a course of antibiotics. If you think you have thrush speak with your doctor or pharmacist for advice.

  • Some antacids may reduce the amount of cefaclor your body absorbs. Because of this, it is recommended that you do not take indigestion remedies during the two hours before or during the two hours after you take cefaclor.

  • If you are using oral combined hormonal contraception (the 'pill'), additional contraceptive precautions such as condoms are recommended for a time if you have sickness (vomiting) or diarrhoea which lasts for more than 24 hours. If you need further advice about this, speak with your doctor or pharmacist.

  • Cefaclor may stop the oral typhoid vaccine from working. If you are having any vaccinations, make sure the person treating you knows that you are taking this medicine.

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Can cefaclor cause problems?

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with cefaclor. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.


cefaclor side-effects

What can I do if I experience this?


Drink plenty of water to replace any lost fluids. If the diarrhoea continues, becomes severe, or contains blood, let your doctor know


Feeling sick (nausea) or being sick (vomiting)

Stick to simple foods. If you are not already doing so, try taking your doses after meals

Skin rash (particularly in children), and other allergic-type reactions

Let your doctor know as soon as possible as your treatment may need to be changed

Important: if you develop an itchy rash, a swollen face or mouth, or have difficulty breathing, these can be signs that you are allergic to the antibiotic. Do not take any more cefaclor, and speak with your doctor or go to your local accident and emergency department straightaway.

If you experience any other symptoms which you think may be due to this medicine, speak with your doctor or pharmacist for further advice.

How to store cefaclor

  • Keep all medicines out of the reach and sight of children.

  • Store in a cool, dry place, away from direct heat and light.

  • If you have been given liquid medicine, store it in a refrigerator. It will have been made up by the pharmacy and lasts for 14 days, so check the expiry date on the bottle and do not use it after this date.

Important information about all medicines

Important information about all medicines

Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital. Take the container with you, even if it is empty.

This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.

If you buy any medicines, check with a pharmacist that they are safe to take with your other medicines.

If you are having an operation or any dental treatment, tell the person carrying out the treatment which medicines you are taking.

Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.

If you have any questions about this medicine ask your pharmacist.

Report side effects to a medicine or vaccine

If you experience side effects, you can report them online through the Yellow Card website.

Further reading and references

Article history

The information on this page is written and peer reviewed by qualified clinicians.

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