Cefalexin (Cephalexin)
Key facts
- Cefalexin (also known as cephalexin) is a medicine in a class of antibiotics known as cephalosporins.
- Cefalexin is an antibiotic that can kill certain types of bacteria that cause infections.
- It’s important to always finish the full course of cefalexin as prescribed by your doctor, to fully treat the infection.
- Most side effects caused by cefalexin are minor, and include nausea, vomiting, diarrhoea and headache.
- If you are allergic to cephalosporin medicines, or penicillin, you should also check with your doctor or pharmacist before taking cefalexin.
LOOKING FOR A MEDICINE? — See this list of medicines that contain cefalexin to find out more about a specific medication.
What is cefalexin?
Cefalexin (also known as cephalexin) is a prescription medicine in a class of antibiotics known as cephalosporins.
What is cefalexin used for?
Cefalexin (cephalexin) is an antibiotic that can kill certain types of bacteria that cause infections.
Cefalexin is used to treat bacterial infections in various parts of the body. This includes infections of your airways (chest and lungs), throat, sinuses, ears, skin and soft tissue, kidneys and bladder.
How does cefalexin work?
Cefalexin (cephalexin) works by killing some types of bacteria that cause an infection.
It’s important to always finish the full course of cefalexin as prescribed by your doctor to fully treat the infection. If you don’t, you risk the infection returning.
What types of cefalexin might I be prescribed?
Cefalexin (cephalexin) is the name of the active ingredient. It is available in many different brands, which may have different:
- names
- appearances (size, shape or colour)
- forms (capsules and suspension)
- packaging
No matter which brand you are prescribed, cefalexin works in the same way to treat your infection.
Cefalexin is only available in Australia with a doctor’s prescription.
What should I do if I cannot get my cefalexin?
Currently, there is a shortage of some antibiotics in Australia, such as amoxicillin, cefalexin and metronidazole.
If you cannot get the medication that you need, speak to your pharmacist or doctor. They can advise on alternatives. For more information, visit Therapeutic Goods Administration (TGA).
What are the possible side effects of cefalexin?
Cefalexin (cephalexin) helps to treat many infections, although some strains of bacteria are resistant to it.
The more common side effects include:
- oral or vaginal thrush (a type of yeast infection in the mouth or vagina)
- diarrhoea
- nausea and/or vomiting
- dizziness
- tiredness or weakness
- abdominal pain
- headache
Serious side effects are very rare.
If you experience sudden, severe signs of allergy — stop taking the medicine and to the emergency department of your nearest hospital.
These include:
- swelling of the face, lips, tongue, or other part of the body
- difficulty breathing, shortness of breath or wheezing
- rash, itching or hives on your skin
For more information about possible side effects, read the Consumer Medicines Information (CMI) on cefalexin that comes with your medicine, or speak to your doctor or pharmacist.
Who should not take cefalexin?
You should not take cefalexin (cephalexin) if you are allergic to it or other medicines classified as cephalosporins. Ask your doctor or pharmacist if you are not sure.
If you are allergic to penicillin, you should also check with your doctor or pharmacist before taking cefalexin. Some people with a penicillin allergy may also be allergic to cephalosporin antibiotics.
Some medicines interact with cefalexin. So it’s important to let your doctor know about any other medicines you take, including over-the-counter or herbal medicines.
When should I see my doctor?
You should also contact your doctor immediately if you develop severe stomach pain or severe watery or bloody diarrhoea along with a fever, especially if this happens several weeks after stopping cefalexin treatment.
You should also speak to your doctor if you:
- experience side effects that trouble you
- have a health condition or are taking medicine that may affect how your body reacts to cefalexin
- become pregnant or start breastfeeding
FIND A HEALTH SERVICE — The Service Finder can help you find doctors, pharmacies, hospitals and other health services.
ASK YOUR DOCTOR — Preparing for an appointment? Use the Question Builder for general tips on what to ask your GP or specialist.
Are there alternatives to cefalexin?
If you can’t take cefalexin (cephalexin), there are other antibiotics that you can take instead. Your doctor will be able to prescribe a different medicine if you can’t take cefalexin.
Resources and support
Ask about your treatment or medicine, as this is important to help you understand your options. Read our guide on important questions to ask your pharmacist or doctor before taking a medicine.
You can also visit healthdirect's list of medicines that contain cefalexin to read the CMI for the brand of cefalexin your doctor has prescribed for you.
Learn more here about the development and quality assurance of healthdirect content.
Last reviewed: April 2023
