A cephalosporin antibiotic
Cefaclor
A cephalosporin antibiotic used for some chest, ear, urinary and skin infections.
What is Cefaclor?
Cefaclor is a cephalosporin antibiotic that treats certain bacterial infections, such as some chest, ear, urinary and skin infections. It is taken by mouth for the full course your prescriber recommends. People with a serious penicillin allergy should mention it, because there can sometimes be cross-reactivity between the two groups.
Education and reference only. This is a plain-language guide to Cefaclor — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Cefaclor is an oral cephalosporin antibiotic, a class closely related to the penicillins. It is used for a range of common bacterial infections, including some respiratory, ear, urinary tract and skin or soft-tissue infections, when it is a suitable choice. It is taken as a course over several days.
How it works
Cefaclor kills bacteria by interfering with the building of their cell wall, the protective outer layer that bacteria need to survive. With the wall weakened, the bacteria break apart and die. This is the same broad approach used by penicillins, which is why the two groups are chemically related.
Practical use
How to take Cefaclor
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take the medicine at evenly spaced times through the day, as prescribed.
- Swallow capsules with water; the liquid is useful for those who cannot manage capsules.
- It can be taken with or without food, but taking it with food may ease any stomach upset.
- Finish the whole course even if you feel better, unless told to stop.
- Tell your prescriber about any previous penicillin or antibiotic allergy before starting.
Weighing it up
Advantages & disadvantages of Cefaclor
Advantages
- Treats a useful range of common infections.
- Taken by mouth at home as capsules or a liquid.
- Generally well tolerated by most people who take it.
Disadvantages
- Should be used with caution if you have a serious penicillin allergy, due to possible cross-reactivity.
- Like all antibiotics, can cause diarrhoea and disturb the gut's natural bacteria.
- Needs the full course completing to work properly and limit resistance.
Practical use
Good to know
Finish the whole course even once you feel better, to clear the infection and reduce resistance. It can usually be taken with or without food; taking it with food can help if it upsets your stomach. Tell your prescriber if you have ever had a serious reaction to penicillin, as there is a small chance of cross-reactivity with cephalosporins.
Who should not take it / use with caution
- People who have had a serious allergic reaction (such as anaphylaxis) to a cephalosporin antibiotic.
- Used with caution in those with a significant penicillin allergy, because of possible cross-reactivity.
- Dose and suitability are reviewed in significant kidney problems.
Monitoring
- Response of the infection and completion of the course
- For any rash or signs of allergy
- Kidney function where relevant
Side effects
- Diarrhoea, nausea or stomach upset.
- Thrush, or a skin rash; tell your prescriber about any rash, as it may signal an allergy.
- Rarely, a severe allergic reaction (facial swelling, breathing difficulty) needing emergency care, or persistent severe diarrhoea that should be reported.
Key interactions
- Probenecid can raise cefaclor levels in the body.
- Can occasionally increase the effect of warfarin, so monitoring may be needed.
- Antacids may slightly reduce absorption of some formulations — check with your pharmacist.
Available as: Capsules and an oral liquid (suspension).
Answers
Cefaclor: frequently asked questions
Can I take cefaclor if I am allergic to penicillin?
Tell your prescriber about your allergy first. Cephalosporins like cefaclor are related to penicillins, and a small number of people who react to one can react to the other, so the decision is made carefully — especially if your penicillin reaction was severe.
Should I take it with food?
It can be taken with or without food. If it upsets your stomach, taking it with a little food can help, and this does not stop it working.
Do I need to finish the whole course?
Yes, unless your prescriber tells you to stop. Completing the course clears the infection fully and helps prevent the bacteria becoming resistant, even if you feel better sooner.
Is cefaclor the same as Distaclor?
Yes. Cefaclor is the active-ingredient (generic) name and Distaclor is a brand name; they contain the same antibiotic.
What should I do if I get diarrhoea?
Mild diarrhoea is common with antibiotics. If it becomes severe, watery, or lasts beyond the course, contact your prescriber, as occasionally antibiotics can trigger a more serious bowel infection that needs treatment.
The wider class
About Cephalosporins
Cefaclor belongs to the cephalosporins class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
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Authoritative sources
- BNF: Cefaclor.
- NICE CKS: Antibiotics.
- electronic Medicines Compendium (SmPC): Cefaclor.
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