Co-Amoxiclav is what’s known as a broad-spectrum antibiotic. Antibiotics are used to treat all kinds of bacterial infections. Broad-spectrum means that these types of antibiotics can be used to help target a wide range of different infections. 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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Common infections like respiratory infections, ear infections and urinary tract infections can make life a misery. They can cause all sorts of pain at the infection site and around the body and often a fever too. These type of infections are caused by different types of bacteria. Viral illness can present similarly and are more common, only a doctor can help discern the difference between a bacterial and a viral illness.

What is Co-Amoxiclav? 

Co-Amoxiclav is what’s known as a broad-spectrum antibiotic. Antibiotics are used to treat all kinds of bacterial infections. Broad-spectrum means that these types of antibiotics can be used to help target a wide range of different infections. A doctor may prescribe these particular antibiotics in specific infections. 

An antibiotic is a chemical which has the potential to slow down the growth of a bacteria or indeed kill it.  Amoxicillin, the antibiotic ingredient in Co-Amoxiclav, belongs to the penicillin group of antibiotics. 

Co-Amoxiclav is a combination antibiotic because it contains amoxicillin and clavulanic acid. The reason that these two drugs have been combined is that clavulanic acid helps to stop the bacteria from breaking down the amoxicillin. This means that the antibiotic can work more effectively. 

When is Co-Amoxiclav used? 

Co-Amoxiclav can be used to treat bacterial infections in both adults and children. It is often used to treat the following kinds of illness: 

  • Ear, nose and throat infections; 
  • Respiratory tract infections; 
  • Urinary tract infections; 
  • Joint and bone infections; 
  • Dental infections; 
  • Skin infections; 
  • Animal bites 

This is not a complete list and you may find you are prescribed Co-Amoxiclav for another type of infection that isn’t listed here.  

How do you use Co-Amoxiclav? 

You should always follow the instructions given to you by your doctor or health professional when it comes to taking any medication.  

Co-Amoxiclav usually comes in tablet form, the tablet is coated with a thin film. This medicine is also available as a liquid. The liquid is usually reserved for use with people with swallowing difficulty. 

As a general rule, you will take Co-Amoxiclav three times a day for up to two weeks. 

  • Take the tablet before, during or after food (it doesn’t matter when you take it as it is not affected by food and drink); 
  • Space the doses out evenly throughout the day, make sure they are at least 4 hours apart; 
  • Do not take two doses in one hour; 
  • Swallow the tablet whole with a glass of water, do not chew it or break it up. 

If you forget to take your tablet at the right time, then take it as soon as you remember, then wait at least four hours before you take the next one. Do not take a double dose to make up for missing a dose, if you’ve missed a dose and then just skip it and carry on with your timed, regularly spaced doses.  

If you have trouble remembering to take your doses try setting an alarm or timing the doses for when you are more likely to remember them, at mealtimes for example. 

What dosages are there? 

Co-Amoxiclav comes as a film-coated tablet. It is available in two different strengths: 

  • 250mg/125g; 
  • 500mg/125g. 

You should take one tablet three times a day, no matter which strength tablet you are using. Take them at regular, evenly spaced times, for example, 7 am, 3 pm and 11 pm. You can adjust the timings to suit your own lifestyle as long as you still take them at evenly spaced times and three times a day. 

The dose required may be lower for children as it will be worked out using their weight. Your doctor will tell you the right dose for your child. 

Always take the full course of antibiotics, do not stop taking your tablets as soon as the symptoms disappear as although on the surface things seem ok, underneath your body is probably still fighting the infection. If you stop taking your tablets before you finish the course the infection may return and you may then require further treatment. 

You will usually take a course of Co-Amoxiclav that lasts for somewhere between 5 and 10 days. It is unlikely you would be prescribed a course that lasts longer than 10 days. 

What are the side effects of Co-Amoxiclav? 

As with all medicines, Co-Amoxiclav does come with some side effects, not everyone who takes this medicine will experience the side effects. 

One potentially serious side effect is an allergic reaction. 

Signs of an allergic reaction: 

Fever, joint pain, swollen glands; 

  • Swelling of the face or mouth causing breathing difficulties; 
  • Collapsing; 
  • Rashes on the skin, blisters, peeling skin – particularly around the nose, mouth, eyes and genitals; 
  • Reddening skin, dark sports with a pale ring around them; 
  • Flu-like symptoms with a rash, fever and swollen glands. 

Seek immediate medical assistance if you believe you may be having an allergic reaction to the medication. 

If you have any of the following side effects whilst taking Co-Amoxiclav then speak to your doctor right away. 

  • Stomach pain with a high temperature – this is a sign that the large intestine is inflamed; 
  • Watery diarrhoea, often with blood and mucus; 
  • Pale poo or dark pee, yellow skin or whites of the eyes – these are signs of a gall bladder problem. 

A very common side effect that affects more than 1 in 10 adults is diarrhoea. Make sure you drink plenty of fluids if you experience this and speak to your doctor if it continues 

Side effects affecting up to 1 in 10 people: 

  • Nausea; 
  • Vomiting; 
  • Thrush; 
  • Diarrhoea (in children). 

Less common side effects, affecting up to 1 in 100 people are: 

  • Rashes and itching; 
  • Hives; 
  • Headaches; 
  • Indigestion; 
  • Dizziness. 

You may also have an increase of enzymes in your liver which will show up in a blood test 

The following side effects may also occur, although they are rare and occur in less than 1 in 1000 people taking Co-Amoxiclav: 

  • Low white blood cell count; 
  • A low number of cells involved in blood clotting; 
  • Black tongue; 
  • Hyperactivity; 
  • Inflammation of tubes in the kidney. 

You should discuss any side effects with your doctor as they may be able to help you feel better them by changing medication or doses. 

When shouldn’t you use Co-Amoxiclav? 

Do not take Co-Amoxiclav is you are allergic to clavulanic acid,  amoxicillin,  penicillin or any of the other ingredients that are listed on the packet. 

You should also avoid Co-Amoxiclav if you’ve ever had an allergic reaction to any kind of antibiotic or if when taking antibiotics this has caused liver problems or jaundice. 

Talk to your doctor or pharmacist before starting treatment with Co-Amoxiclav if any of the following apply: 

  • You have glandular fever; 
  • You aren’t urinating regularly; 
  • You are being treated for liver or kidney problems. 

You can take Co-Amoxiclav if you are pregnant or breastfeeding, or think you may be pregnant but you should discuss this with your doctor before you start as there may be a better option for you and your baby. 

If you experience side effects like dizziness and nausea, do not drive or operate heavy machinery while taking Co-Amoxiclav as it could cause an accident. 

Does Co-Amoxiclav interact with other medication? 

Always tell your doctor or pharmacist if you are taking any other medication, including herbal supplements as these may interact with Co-Amoxiclav and either prevent it from working or reduce its efficiency or Co-Amoxiclav may affect the medication you are already taking. 

In particular please note the following: 

  • If you are taking allopurinol for gout then your skin is more likely to experience an allergic reaction if you take Co-Amoxiclav; 
  • If you are taking probenecid for gout then you may need to adjust the dose of Co-Amoxiclav; 
  • If you are taking medicines to prevent blood clots, like warfarin, then you made need to have extra blood tests throughout your treatment. 

You will also need to be careful with the following medicines: 

  • Methotrexate and allopurinol which are used to treat rheumatic diseases; 
  • Mofetil, which is used after an organ transplant to help the body accept the organ and some anticoagulant medication. 

Can I get Co-Amoxiclav without a prescription? 

No, you must have a prescription to get Co-Amoxiclav. The decision to treat your condition with antibiotics must be made by a doctor in person after a face to face consultation. 

To get a prescription you can visit your local GP or walk-in centre. Once you have been advised that you need antibiotics then you can arrange an online consultation to order your antibiotics, where a doctor will double check all the information and provide the necessary treatment if safe to do so. 


Cucic, A. (2019). Broad Spectrum Antibiotics | Med Health Daily. [online] Available at: [Accessed 19 Nov. 2019]. (2019). Co-amoxiclav, a medicine for treating bacterial infections. [online] Available at: [Accessed 19 Nov. 2019]. 

Sun Pharmaceuticals Industries Europe BV (2018). [online] Available at: [Accessed 19 Nov. 2019] 

Antimicrobial resistance: risk associated with antibiotic overuse and initiatives to reduce the problem

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.