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.
- Take flucloxacillin on an empty stomach. This means at least 30 to 60 minutes before a meal or snack, and at least 2 hours after.
- For most infections, you should start to feel better within a few days.
- The most common side effects are feeling sick (nausea) and diarrhoea.
- You can drink alcohol while taking flucloxacillin.
- You can take flucloxacillin during pregnancy or while you're breastfeeding.
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:
- have ever had an allergic reaction to penicillin, flucloxacillin or any other medicine
- have liver or kidney problems
- have recently had, or are due to have, any vaccinations
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.
Common side effects
Like all medicines, flucloxacillin can cause side effects in some people, although not everyone will get them.
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:
- feeling sick (nausea) or being sick (vomiting)
- bloating and indigestion
Serious side effects
Serious side effects are rare and happen in less than 1 in 1,000 people.
Call a doctor or contact 111 straight away if:
- you get diarrhoea (possibly with muscle cramps) that contains blood or mucus, or severe diarrhoea that lasts more than 4 days
- you have pale poo with dark pee, and the whites of your eyes or skin turn yellow (this may be less obvious on black or brown skin) – this can be a sign of liver problems
- you get bruising or discoloured skin
- you have joint or muscle pain that starts happening after 2 days of taking the medicine
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:
- feeling sick or being sick – stick to simple meals and try not to eat rich or spicy food. If you are being sick, take small, frequent sips of fluids such as water or squash to stop getting dehydrated. Signs of dehydration include peeing less than usual or having dark, strong-smelling pee. If you take contraceptive pills and you're being sick, your contraception may not protect you from pregnancy. Check the pill packet to find out what to do.
- diarrhoea – drink lots of fluids such as water or squash to stop getting dehydrated. Signs of dehydration include peeing less than usual or having dark, strong-smelling pee. Do not take any other medicines without speaking to a pharmacist or doctor. If you take contraceptive pills and you have severe diarrhoea, your contraception may not protect you from pregnancy. Check the pill packet to find out what to do.
- bloating and indigestion – try not to eat foods that cause farting (flatulence), like lentils, peas, beans and onions. You could also try eating smaller meals, eating and drinking more slowly, and exercising regularly.
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:
- your baby is not feeding as well as usual
- they have sickness or diarrhoea
- your baby has oral thrush or a skin rash
- you have any other concerns about your baby
Cautions with other medicines
Mixing flucloxacillin with herbal remedies and supplements
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:
- methotrexate, an anti-inflammatory medicine for arthritis and similar conditions
- warfarin, a medicine to prevent blood clots
- other antibiotics
Tell your doctor if you've recently had, or are due to have, an oral typhoid vaccination. Flucloxacillin can make it less effective.
There is little information about taking herbal remedies and supplements with flucloxacillin.