What is cefalexin?

Cefalexin (also known as cephalexin) is a prescription medicine in a class of antibiotics known as cephalosporins. Cefalexin works by killing the bacteria causing infection. Your doctor may prescribe it if you have a type of bacterial infection that can be killed by cefalexin.

How does cefalexin work?

Cefalexin (cephalexin) works by killing some types of bacteria that cause an infection.

It's important to take cefalexin as prescribed by your doctor to fully treat the infection. If you don't, you risk the infection returning.

What is cefalexin used for?

Cefalexin (cephalexin) is an antibiotic that can be used to treat bacterial infections in various parts of the body including in your:

• chest and lungs
• throat and sinuses
• ears
• skin and soft tissue
• kidneys and bladder

Your doctor may have prescribed cefalexin for another reason. If you are not sure why you were prescribed cefalexin, ask your doctor.

What forms of cefalexin are available?

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 oral liquid)
• packaging

No matter which brand you are prescribed, cefalexin works in the same way to treat your infection.

Cefalexin is generally only available in Australia with a doctor's prescription. Some pharmacists may prescribe cefalexin for treatment of UTIs. This can depend on where you live in Australia. Also, pharmacists can only prescribe antibiotics for certain people. Males, children and pregnant people cannot get antibiotics for a UTI without seeing a doctor.

Your doctor or pharmacist may also recommend pain-relief medicines to treat any pain and discomfort.

What should I do if I cannot get my cefalexin?

Sometimes, there are shortages of some antibiotics in Australia. If you cannot get the medicines that you need, speak to your pharmacist or doctor. They can advise on alternatives.

What are the possible side effects or risks of cefalexin?

All medicines have benefits but also the risk of side effects. If you have any concerns speak to your doctor.

The more common side effects of cefalexin (cephalexin) 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. 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
• confusion, seizures or memory loss

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.

Cefalexin (cephalexin) may treat many infections, although some strains of bacteria are resistant to it.

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. It's important to let your doctor know about any other medicines you take, including over-the-counter or herbal medicines.

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.

How do I take cefalexin?

Your doctor or pharmacist will tell you how often and for how many days to take cephalexin.

Make sure to follow their instructions carefully. Continue taking cefalexin until you finish the prescription, or for the full period your doctor advises.

If you are prescribed cefalexin tablets, swallow the tablet with a glass of water. If you are prescribed cefalexin in liquid form, make sure you shake the bottle before taking the medicine. You can take it with or without food.

Try to take cefalexin at the same time every day to ensure it works effectively. If you forget a dose:

• If it is close to the usual time — take it as soon as you remember and then keep taking it at the usual times.
• If it is almost time for your next dose — skip the missed dose and take the next one at the usual time. Then continue as normal. Do not take a double dose.

Speak to your doctor or pharmacist if you are unsure what to do.

When should I see my doctor?

Contact your doctor immediately if you develop:

• severe stomach pain
• severe watery or bloody diarrhoea along with a fever

This is especially important if these symptoms occur several weeks after stopping cefalexin treatment. Do not take diarrhoea medicine in this situation without talking to your doctor.

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, are planning to become pregnant or start breastfeeding

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 check healthdirect's list of medicines that contain cefalexin, to read the CMI for the brand your doctor has prescribed for you.

Do you prefer to read in languages other than English?

You can find translated information about medicines on the NPS MedicineWise website.

Looking for information for Aboriginal and/or Torres Strait Islander people?

The National Aboriginal Community Controlled Health Organisation website has resources on medicines, side effects and more.