About flucloxacillin

Flucloxacillin is an antibiotic.

It's used to treat:

Flucloxacillin is only available on prescription.

It comes as capsules or as a liquid that you swallow. It can also be given by injection, but this is usually done in hospital.

Key facts

Who can and cannot take flucloxacillin

Flucloxacillin can be taken by adults, including throughout pregnancy and while breastfeeding. Flucloxacillin can also be taken by children.

To make sure flucloxacillin is safe for you, tell your doctor if you:

How and when to take flucloxacillin


The usual dose of flucloxacillin is 250mg to 500mg, taken 4 times a day. For children, the dose may be lower.

Try to space your doses evenly throughout the day. For example, first thing in the morning (before breakfast), at around midday (before lunch), late in the afternoon (before tea) and at bedtime.


Carry on taking this medicine until you've finished all your tablets, capsules or liquid, even if you feel better. If you stop your treatment early, your symptoms could come back.

How to take it

Swallow flucloxacillin capsules whole with a drink of water. Do not chew or break them.

It's best to take flucloxacillin on an empty stomach. That means taking it at least 30 to 60 minutes before a meal or snack, and at least 2 hours after.

Liquid flucloxacillin is available for children, and people who find it difficult to swallow capsules.

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

If you forget to take it

If you forget to take a dose, take it as soon as you remember, unless it's nearly time for your next dose. If this happens, just leave out the missed dose and take your next dose at the usual time.

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 your pharmacist for advice on other ways to help you remember to take your medicine.

If you take too much

Try to take the right number of doses each day, leaving at least 3 hours between doses.

Taking an extra dose of flucloxacillin is unlikely to harm you or your child.

Talk to your pharmacist or doctor if you're worried or if you take more than 1 extra dose.

Side effects

Like all medicines, flucloxacillin can cause side effects in some people, although not everyone will get them.

Common side effects

Common side effects of flucloxacillin happen in more than 1 in 100 people. Keep taking the medicine, but tell your doctor or pharmacist if these side effects bother you or do not go away:

Serious side effects

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

Call a doctor or call 111 straight away if:

Some of these serious side effects may not happen for up to 2 months after finishing the course of flucloxacillin.

Serious allergic reaction

In rare cases, it's possible to have a serious allergic reaction (anaphylaxis) to flucloxacillin.

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

How to cope with side effects of flucloxacillin

What to do about:

Pregnancy and breastfeeding

Flucloxacillin and pregnancy

It's safe to take flucloxacillin during pregnancy.

Flucloxacillin and breastfeeding

It is OK to take flucloxacillin while breastfeeding.

Information shows that only tiny amounts of flucloxacillin get into breast milk, which would not be expected to cause any side effects in your baby.

Talk to your doctor, pharmacist, health visitor or midwife if:

Cautions with other medicines

Some medicines can affect the way that flucloxacillin works and increase the chance of you having side effects.

Tell your doctor if you're taking any of these medicines before you start flucloxacillin:

Tell your doctor if you've recently had, or are due to have, an oral typhoid vaccination. Flucloxacillin can make it less effective.

Mixing flucloxacillin with herbal remedies and supplements

There is little information about taking herbal remedies and supplements with flucloxacillin.

Common questions about flucloxacillin

How does flucloxacillin work? When will I feel better? What if I do not get better? Will it give me thrush? Will it affect my contraception? Will it reduce my fertility? Can I drive or ride a bike? Can I drink alcohol with it? Is there any food or drink I need to avoid?