Flucloxacillin is an antibiotic.

It's used to treat skin and wound infections, chest infections, such as pneumonia, and bone infections.

Flucloxacillin is used in children, often to treat ear infections and chest infections.

The medicine is available as capsules or as a liquid that you drink. It can also be given by injection, but this is usually done in hospital.

  1. Key facts

    • Take flucloxacillin on an empty stomach. This means 30 to 60 minutes before a meal or snack, or at least 2 hours after.
    • For most infections, you should feel better within a few days.
    • The most common side effects are feeling sick and diarrhoea.
    • You can drink alcohol while taking flucloxacillin.
    • Flucloxacillin is called by the brand name Floxapen.
  2. Who can take flucloxacillin

    Flucloxacillin can be taken by adults, including pregnant and breastfeeding women.

    Flucloxacillin can be taken by children.

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

    • have an allergy to penicillin or flucloxacillin
    • have liver or kidney problems
    • have recently had, or are about to have, any vaccinations
  3. How and when to take

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

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

    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 completed the course, even if you feel better. If you stop your treatment early, your problem could come back.

    How to take it

    Swallow flucloxacillin capsules whole with a drink of water. Don't chew or break them.

    There's a liquid flucloxacillin available for children and people who find it difficult to swallow tablets.

    If you or your child are taking flucloxacillin as a liquid, it'll 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 don't have a syringe or spoon, ask your pharmacist for one.

    What if I forget to take it?

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

    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 that are suitable for you and your medicines.

    What if I take too much?

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

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

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

  4. Side effects

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

    Common side effects

    These common side effects of flucloxacillin happen in more than 1 in 100 people. Keep taking the medicine, but tell your doctor if they bother you or don't go away:

    • feeling sick
    • vomiting
    • diarrhoea
    • upset stomach
    • bloating and indigestion

    Serious side effects

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

    Tell a doctor straight away if you get:

    • severe, bloody diarrhoea
    • yellowing of the whites of the eyes and skin
    • a severe skin rash, including flushing, fever, blisters or ulcers, round red patches, or skin that looks like it's been burnt
    • bruising or discoloured skin
    • joint or muscle pain that comes on after 2 days of taking the medicine
    • dark pee

    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 to flucloxacillin. The warning signs of a serious allergic reaction are:

    • getting a skin rash that may include itchy, red, swollen, blistered or peeling skin
    • wheezing
    • tightness in the chest or throat
    • having trouble breathing or talking
    • swelling of the mouth, face, lips, tongue or throat

    A serious allergic reaction is an emergency. Contact a doctor straight away if you think you or someone around you is having a serious allergic reaction.

    These are some of the side effects of flucloxacillin. For a full list, see the leaflet inside your medicine packet.

  5. How to cope with side effects

    What to do about:

    • feeling sick – stick to simple meals and try not to eat rich or spicy food
    • diarrhoea and vomiting – drink plenty of water or other fluids. It may also help to take oral rehydration solutions you can buy from a pharmacy to prevent dehydration. Don't take any other medicines to treat diarrhoea or vomiting without speaking to a pharmacist or doctor

    You can report any suspected side effect to a UK safety scheme.

  6. Pregnancy and breastfeeding

    Flucloxacillin can generally be taken in usual doses during pregnancy and while breastfeeding.

    However, for safety, tell your doctor if you're pregnant or breastfeeding before taking this medicine.

  7. Cautions with other medicines

    There are some medicines that don't mix well with flucloxacillin.

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

    • methotrexate
    • a blood thinner called warfarin
    • other antibiotics

    You should also let your doctor know if you've recently had, or are about to have, any vaccinations.

    Mixing flucloxacillin with herbal remedies and supplements

    There are no known problems with taking herbal remedies and supplements with flucloxacillin.

    However, for safety, tell your doctor and pharmacist if you're taking any other medicines, including herbal remedies and supplements.

  8. Common questions