Flucloxacillin is a form of penicillin based antibiotic typically used to treat skin infections, certain chest and bone infections. Flucloxacillin can sometimes be used for other conditions too. More information

A doctor will review your order and write you a prescription, if appropriate. This prescription is then forwarded to a pharmacy. The pharmacy will have your medicine delivered to you within one to three working days. Read more about this process here.

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Patient Leaflet(s)

Flucloxacillin is a form of penicillin-based antibiotic. The active ingredient in this medication is Flucloxacillin, which works to kill certain bacteria, cure bacterial infections, and provide relief from symptoms such as pain, redness, fever, swelling, and general discomfort.  

What is Flucloxacillin? 

Flucloxacillin is a form of penicillin based antibiotic typically used to treat skin infections, certain chest and bone infections. Flucloxacillin can sometimes be used for other conditions too. Available in a range of strengths and in liquid form, this medication can either be prescribed by a doctor in pill form or given by injection at a hospital.  

Flucloxacillin belongs to the penicillin range of antibiotics, and it works by interfering with the formation of the cell walls that bacteria create. The medication impairs the bonds that hold the walls of the bacterial cell together, which causes holes to appear in the walls and kills off the bacteria causing the infection.  

Flucloxacillin differs from other kinds of penicillin antibiotics. Usually, when bacteria become resistant to antibiotics based on penicillin, they produce an enzyme that can attack the antibiotic and stop it from becoming effective at killing bacteria. However, Flucloxacillin isn’t affected by this enzyme, which means it can be often used for the treatment of infections that are caused by bacteria resistant to other medications.  

When is Flucloxacillin used? 

Flucloxacillin is usually recommended for the treatment of infections caused by certain kinds of bacteria. This medication is most likely to be prescribed to people who are resistant to other forms of medication that contain penicillin.  

Flucloxacillin can treat boils, abscesses, cellulitis, ulcers, impetigo, eczema, ulcers, burns and wounds. Specific chest infections, lung abscesses, and pneumonia can also be treated by Flucloxacillin.  

As a wide-spectrum antibiotic, Flucloxacillin can also be used for the treatment of a wide range of other infections, including: 

  • Blood infections; 
  • Bacterial meningitis; 
  • Skin or soft tissue infections; 
  • Urinary tract infections
  • Bacterial infections of the heart valves; 
  • Infections of the intestine. 

In certain circumstances, doctors may also prescribe Flucloxacillin to help prevent bacterial infections that occur during major surgery. This will help to ensure that the patient receiving the surgery can recover as quickly as possible.  

How do you use Flucloxacillin? 

Flucloxacillin is a potent antibiotic. It is important to ensure that you read the instructions printed on the manufacturer’s label before you begin taking this medication to ensure that you are using it correctly. Additionally, it may be a good idea to ask your consultant any questions that you have about using this medication.  

Before you begin using this substance, ensure that you know exactly how often you need to take the substance, and how long you should be using it for. Flucloxacillin works best on an empty stomach – which means that you should take it about an hour before eating. Alternatively, you can have your dose two hours after having your food. This is because your body will be less likely to absorb Flucloxacillin when having a meal, making the medication less effective.  

When taking Flucloxacillin multiple times in a day, attempt to spread the doses out evenly throughout the day. You should swallow this medication whole, without opening or chewing them. Additionally, some people find that it’s useful to swallow the capsules with a drink of water. You should not double up on your dose of Flucloxacillin if you forget to take one. If you forget to take a dose, take the dose when you remember, without adding extra medication to your schedule.  

If you think that your infection has cleared up, you should still continue taking this antibiotic until you have finished the complete course. You should not stop taking any antibiotic ahead of schedule, even if your symptoms go away. Stopping using an antibiotic early can increase your chances of the infection from returning and becoming resistant to your medication.  

What dosages are there? 

Flucloxacillin comes in two different doses, 250mg, and 500mg. You will be given a dose depending on a number of factors, including which condition you are attempting to treat, and what your response to other medications has been. You should take Flucloxacillin exactly as advised to do so by your doctor. Usually, this medication will need to be taken four times per day. However, your doctor or consultant will tell you how many capsules, or how much liquid medication you should be taking.  

If you have been given liquid medication, it is important to measure the doses carefully using the equipment provided to you. Each dose of Flucloxacillin needs to be taken on an empty stomach to improve your chances of absorbing the medication fully into your system and recovering from your infection as quickly as possible.  

What are the side effects of Flucloxacillin? 

Flucloxacillin is a well-tolerated antibiotic. However, all medications, including antibiotics like Flucloxacillin can sometimes cause responses that are not intended. This is usually the case when the medication responds poorly with something in your system. It is important to be aware of the possible side effects associated with taking Flucloxacillin, so you know when you should be seeking help from a medical professional.  

Remember, just because a side effect is mentioned here or in your patient leaflet doesn’t mean that you will definitely experience it. Many people will be able to take Flucloxacillin without any negative responses at all. Other people will find that the common side effects of Flucloxacillin diminish after they have taken the medication for a short amount of time.  

Flucloxacillin can cause common side effects such as: 

  • Sickness and nausea; 
  • Vomiting; 
  • Diarrhea
  • Skin rash. 

It is very unlikely that you will have an allergic reaction to Flucloxacillin. However, you should always keep an eye out for potential signs of an allergy when taking this medication or other medicines. Seek emergency medical attention if you have difficulty breathing when using Flucloxacillin or have a swollen mouth or face after using Flucloxacillin. This could be a sign that you are allergic to penicillin.  

Flucloxacillin can sometimes cause a very specific kind of diarrhea that is caused by a type of resistant bacteria in your system. If you notice any mucus or blood in your bowel movements, or have severe stomach pain and diarrhea, you should seek emergency attention from a doctor as quickly as possible. Do not attempt to take medications to stop diarrhea when this happens.  

When shouldn’t you use Flucloxacillin? 

Although Flucloxacillin is suitable for many people to take, it will not be the right treatment for everyone. You should not take this medication if you have ever had an allergic reaction to penicillin or Flucloxacillin in the past, for instance. It’s also a good idea to make sure that your consultant is aware of any allergies that you have to other substances, as there may be inactive ingredients in Flucloxacillin that cause negative responses. 

Make sure that you answer all of the questions asked by your consultant carefully and truthfully when applying to receive Flucloxacillin, this will ensure that the medication is safe for you. Flucloxacillin is not suitable for people who have had liver problems or jaundice in the past when taking Flucloxacillin.  

Certain people may need a lower dose of Flucloxacillin than usual or may be required to have regular monitoring from a medical professional when taking this medication. Make sure that your consultant is aware if you have ever had liver or kidney problems in the past before you begin taking Flucloxacillin. Additionally, because the side effects of this medication are more likely to affect people with serious underlying illnesses, and those over the age of 50, it’s important that your consultant understands your current condition. 

Flucloxacillin can only be taken with regular monitoring and care by people who have a history of allergies like eczema and asthma. Additionally, while this medication is not known to be harmful to parents and children during pregnancy, it is worth speaking to your consultant about your concerns if you  are using this drug when pregnant. You may also need to seek advice when using Flucloxacillin when you are breastfeeding.  

Does Flucloxacillin interact with other medications? 

Flucloxacillin can sometimes react poorly in your system when it is taken at the same time as other medications. Interactions between medications can lead to a higher chance of various side effects and serious responses. It is important that your consultant is aware of any other medications that you are using before you begin taking Flucloxacillin. This includes substances that you have purchased over the counter, and medications bought with a prescription. 

Additionally, ensure that your consultant knows whether you are taking any herbal supplements, as these natural treatments can sometimes have an impact on other drugs too. You can take Flucloxacillin with various painkillers, but it is best to make sure that you are using the painkillers that are suitable for your condition. Additionally, while Flucloxacillin does not affect hormonal contraceptives, if you have diarrhea when taking this medication, it could make your pill less effective. Seek guidance from your consultant or a doctor if you’re unsure whether you might need additional forms of protection.  

Where can you buy Flucloxacillin? 

Your doctor will first need to examine you in person face to face in order to ascertain whether you need antibiotics and the best choice.  

Flucloxacillin is available to purchase after a consultation with one of our professionals. Our consultants will determine whether Flucloxacillin safe for you and can send a prescription to a local pharmacy on your behalf within three working days.  

Can I get Flucloxacillin without a prescription? 

Flucloxacillin is not available without a prescription. You will need a consultant to send a prescription to a local pharmacy for you.  


Drugs.com, online, 2019, “FLUCLOXACILLIN 500MG CAPSULES”, [Accessed 18th of December 2019], Available on: https://www.drugs.com/uk/flucloxacillin-500mg-capsules-leaflet.html 

Medicines.org, online, 2019, “Flucloxacillin 500mg Capsules” [Accessed 18th of December 2019], Available on: https://www.medicines.org.uk/emc/product/4031/smpc 

Mims.co.uk, 2019, “Flucloxacillin” [Accessed 18th of December 2019], Available on: https://www.mims.co.uk/drugs/infections-and-infestations/bacterial-infections/flucloxacillin 

Assessed by:

Dr Imran Malik, General practitioner
Registration number: GMC: 4741365

Dr Imran Malik studied undergraduate medicine at King's College University in Central London and clinical studies at the prestigious King's College Hospital. He graduated with a MBBS degree in 2000 and went on to gain postgraduate memberships with the Royal Society of Medicine and also General Practice in 2006.