Cefalexin

Cefalexin is an antibiotic. It belongs to a group of antibiotics called cephalosporins.

It's used to treat bacterial infections, such as pneumonia and other chest infections, skin infections and urinary tract infections (UTIs).

Cefalexin is only available on prescription. It comes as capsules, tablets or as a liquid that you swallow.

Most adults and children can take cefalexin.

Cefalexin is not suitable for some people.

To make sure cefalexin is safe for you, tell your doctor before starting to take it if you have:

• ever had an allergic reaction to cefalexin or any other medicine
• kidney problems
• ever had a severe skin rash or skin peeling, blistering or mouth sores after taking antibiotics
• had severe or bloody diarrhoea when you've taken antibiotics before

Cefalexin comes as tablets, capsules and a liquid that you swallow.

Your dose of cefalexin will depend on why you're taking it but for most infections, adults usually take 500mg, 2 or 3 times a day.

Your dose may be higher if you have a severe infection and be lower for children.

If you're taking cefalexin capsules or tablets, swallow them whole with a drink of water. Do not chew or break them.

If you or your child are taking cefalexin as a liquid, it will usually be made up for you by a pharmacist. The medicine will come with a plastic syringe or medicine spoon to help you measure the right dose. If you do not have one, ask a pharmacist for one. Do not use a kitchen teaspoon as it will not measure the right amount.

You can take cefalexin with or without food.

Try to space the doses evenly throughout the day. If you take it 3 times a day, this could be first thing in the morning, mid-afternoon and at bedtime.

Your doctor will tell you how long to take cefalexin for, as this can vary depending on the type of infection you have.

Cefalexin is generally used for a short time to treat an infection. It can also be used long-term to prevent infections from coming back.

For some types of infection, you may need to take cefalexin for at least 10 days.

Tell your doctor if you do not start to feel better after taking cefalexin for 2 to 3 days, or if you feel worse at any time.

Do not stop taking it before you're supposed to, as there's a risk the infection could come back. It also gives any remaining bacteria a chance to change or adapt, which means the antibiotic could stop working. This is known as antibiotic resistance.

Keep taking this medicine until you've completed the course, even if you feel better. If you stop your treatment early, the infection could come back.

If you forget to take a dose, take it as soon as you remember, unless it's nearly time for your next dose. In this case, skip the missed dose and take your next dose at the usual time. Try to leave a gap of at least 4 hours between doses.

Never take 2 doses at the same time. Never take an extra dose to make up for a forgotten one.

If you forget doses often, it may help to set an alarm to remind you. You could also ask a pharmacist for advice on other ways to remember your medicines.

Taking 1 extra dose of cefalexin is unlikely to harm you or your child.

Speak to a pharmacist or doctor if you're worried or you take 2 extra doses or more.

These common side effects of cefalexin happen in around 1 in 10 people. There are things you can do to help cope with them:

Eat simple meals and do not eat rich or spicy food while you're taking this medicine. It might help to take your cefalexin after a meal or snack.

Drink lots of fluids, such as water or squash, to avoid dehydration. Signs of dehydration include peeing less than usual or having dark, strong-smelling pee.

Do not take any other medicines to treat diarrhoea. If your diarrhoea continues, speak to a pharmacist or doctor.

If you take the combined contraceptive pill or progestogen-only pill and you have severe diarrhoea for more than 24 hours, your contraception may not protect you from pregnancy. Check the pill packet for advice.

Try to rest and relax. It can help to eat and drink slowly and have smaller and more frequent meals. Try putting a heat pad or covered hot water bottle on your stomach.

Keep taking the medicine, but talk to your doctor or pharmacist if the advice on how to cope does not help and these side effects bother you or do not go away.

Serious side effects are rare and happen in less than 1 in 1,000 people.

Call your doctor or call 111 now if you get:

• severe diarrhoea or there is blood or mucus in your diarrhoea
• pale poo and dark pee, yellowing of your skin (this may be less obvious on brown or black skin), or whites of your eyes – this may be a sign of liver problems
• unexplained bruising on your skin

Serious allergic reaction

In rare cases, cefalexin may cause a serious allergic reaction (anaphylaxis).

Call 999 now if:

• your lips, mouth, throat or tongue suddenly become swollen
• you're breathing very fast or struggling to breathe (you may become very wheezy or feel like you're choking or gasping for air)
• your throat feels tight or you're struggling to swallow
• your skin, tongue or lips turn blue, grey or pale (if you have black or brown skin, this may be easier to see on the palms of your hands or soles of your feet)
• you suddenly become very confused, drowsy or dizzy
• someone faints and cannot be woken up
• a child is limp, floppy or not responding like they normally do (their head may fall to the side, backwards or forwards, or they may find it difficult to lift their head or focus on your face)

You or the person who's unwell may also have a rash that's swollen, raised, itchy, blistered or peeling.

These can be signs of a serious allergic reaction and may need immediate treatment in hospital.

These are not all the side effects of cefalexin. For a full list see the leaflet inside your medicine packet.

You can take cefalexin at any stage during pregnancy. There's no evidence that it causes harm to the baby.

It's important to treat infection during pregnancy as there's a risk that it could make you unwell if left untreated.

It's OK for you to take cefalexin while breastfeeding.

Only tiny amounts of cefalexin get into breast milk, so it does not normally cause any side effects in your baby. However, it has caused diarrhoea in a few infants.

It's important to treat an infection while you're breastfeeding as there's a risk that it could make you unwell if left untreated.

Talk to your health visitor, midwife, doctor or pharmacist as soon as possible if you have any concerns, including if your baby:

• is not feeding as well as usual
• has sickness or diarrhoea
• has oral thrush (a fungal infection in their mouth) or a skin rash

There's no evidence to suggest that cefalexin affects fertility in men or women.

Tell your doctor if you're:

• trying to get pregnant
• pregnant
• breastfeeding

Some medicines do not mix well with cefalexin.

Tell your doctor or pharmacist before starting to take cefalexin if you take any of these medicines:

• probenecid, a medicine used to treat gout
• metformin, a medicine used to treat diabetes
• medicines that make you pee more (diuretics) including furosemide
• other antibiotics

Do not take cefalexin at the same time as zinc supplements or anything with zinc in it. This is important because zinc may reduce the amount of cefalexin in your body, meaning the medicine cannot work as it's meant to.

If you do take supplements with zinc in them, make sure there is a gap of at least 3 hours before and after you take your cefalexin.

There's not enough information to say that other complementary medicines, herbal remedies and supplements are safe to take with cefalexin. They're not tested in the same way as pharmacy and prescription medicines. They're generally not tested for the effect they have on other medicines.

Tell your doctor or pharmacist if you're taking any other medicines, including herbal remedies, vitamins or supplements.