Co-amoxiclav (Augmentin)
Also known as: amoxicillin with clavulanic acid, amoxicillin and clavulanate
A penicillin antibiotic that combines amoxicillin with clavulanic acid, used for bacterial infections such as those of the ears, lungs, sinuses, skin and urinary tract. It is not suitable for people who have had an allergic reaction to it or another antibiotic, or liver problems or jaundice while taking an antibiotic. The NHS lists diarrhoea, nausea and vomiting, and thrush as common side effects.
- Generic name
- Co-amoxiclav (Augmentin)
- Active ingredient
- Co-amoxiclav (Augmentin) (variants: amoxicillin with clavulanic acid)
- Product type
- Small-molecule medicine
- Drug class
- Penicillins
- Brand names
- UK Augmentin
- Routes
- Oral
- Dosage forms
- Tablet, Suspension
- Also known as
- amoxicillin with clavulanic acid, amoxicillin and clavulanate
- Usual preparations
- Available as tablets and as an oral suspension (liquid), according to NHS formularies; injection forms also exist. (summary of the cited reference, not a prescription)
- Monitoring
- UK patient leaflets note that some people with kidney problems may need the treatment changed.
Availability by country
| Country | Status | Note | Source |
|---|---|---|---|
| UK | Prescription only | UK |
Legal status differs between countries and can change; each row cites the document it was taken from and applies only to the country named.
What it is used for
- Infections caused by bacteria, according to the NHS.
- Infections of the ears, lungs, sinuses, skin and urinary tract, as listed by MedlinePlus.
- Sinus, bone and joint, and dental infections, according to UK patient leaflets.
How it works in the body
Co-amoxiclav is an antibiotic that works by killing the bacteria causing an infection. It contains two medicines, amoxicillin and clavulanic acid. MedlinePlus describes amoxicillin as a penicillin-like antibiotic that stops the growth of bacteria, and clavulanic acid as a beta-lactamase inhibitor.
Common side effects
- Diarrhoea, nausea and vomiting, and thrush are the common side effects listed by the NHS.
- The NHS says co-amoxiclav will not usually affect the ability to drive, ride a bike or use machinery.
Serious: seek help
- Anaphylaxis, a severe allergic reaction, can cause swelling of the lips, mouth, throat or tongue or fast or difficult breathing, and the NHS amoxicillin page says to call 999 for these signs.
- Serious skin reactions can include blistering or peeling skin; the NHS says to call NHS 111 if serious side effects are suspected.
- Liver problems can show as pale poo with dark pee, or yellowing of the whites of the eyes or the skin; the NHS says to call NHS 111 if serious side effects are suspected.
- Some UK patient leaflets list inflammation of the large intestine, which causes watery diarrhoea, among the serious side effects; the NHS route for suspected serious side effects is NHS 111.
- Pancreatitis, inflammation of the pancreas, causes severe pain in the stomach or back that does not go away; the NHS says to call NHS 111 if serious side effects are suspected.
Cautions and interactions
- The NHS says most adults and children can take co-amoxiclav, but it is not suitable for everyone.
- It is not suitable for people who have had an allergic reaction to co-amoxiclav or another antibiotic, which can include a skin rash or swelling of the face and throat.
- It is not suitable for people who have had liver problems or jaundice while taking an antibiotic, and MedlinePlus asks that past liver problems after taking it be reported to the doctor.
- The NHS says co-amoxiclav can usually be used in pregnancy if the doctor thinks it is needed, and usually while breastfeeding after checking with a pharmacist or doctor.
- The NHS names gout medicines such as allopurinol or probenecid, warfarin and methotrexate as medicines that may not mix well with it.
- MedlinePlus says amoxicillin and clavulanic acid may decrease the effectiveness of hormonal contraceptives.
- A 2026 NHS Somerset primary care guide advises avoiding broad-spectrum antibiotics such as co-amoxiclav when narrower ones remain effective, because of the risk of C. difficile, MRSA and resistant urinary infections.
Interactions
Check interactions
Taking Co-amoxiclav (Augmentin) with other medicines? Add them to the checker to see what the official sources say about each pair: the mechanism, general management and monitoring, never a bare "safe".
Interactions documented in the official sources cited on each card. The list covers the medicines represented on this site and is not exhaustive; how the interaction data is compiled.
No pair records for this medicine are in the sources currently represented by Anatomy Nexus. Absence from this list does not mean no interaction exists.
Same-class and related medicines
Same class: Penicillins
Medicines that share the class of Co-amoxiclav (Augmentin). They are separate medicines with their own licences, doses and interactions, not alternative names for Co-amoxiclav (Augmentin).
Related medicines
Medicines often discussed alongside Co-amoxiclav (Augmentin): used together, compared with it, or acting on the same problem by a different route.
Key facts
| Fact | Detail |
|---|---|
| Drug class | Penicillin antibiotic combined with clavulanic acid, a beta-lactamase inhibitor |
| Contains | Amoxicillin and clavulanic acid |
| Forms | Tablets and liquid (oral suspension) taken by mouth |
| Common side effects | Diarrhoea, nausea and vomiting, and thrush |
| Not suitable after | An allergic reaction to it or another antibiotic, or liver problems or jaundice from an antibiotic |
| Emergency sign | Sudden swelling of the lips, mouth, throat or tongue, or difficult breathing: call 999 |
What is co-amoxiclav used for?
Co-amoxiclav is an antibiotic, a medicine that treats infections caused by bacteria. The NHS describes it as a penicillin antibiotic for bacterial infections. MedlinePlus says it treats certain infections caused by bacteria, including infections of the ears, lungs, sinuses, skin and urinary tract. UK patient leaflets also list sinus, bone and joint, and dental infections, and note that it has no effect against infections caused by viruses.
The NHS says most adults and children can take it, although it is not suitable for everyone. NHS formularies list it as tablets and as an oral suspension, which is a liquid form, and injection forms also exist. A March 2026 primary care guide from NHS Somerset advises avoiding broad-spectrum antibiotics such as co-amoxiclav when narrower ones remain effective. The reason it gives is the risk of Clostridium difficile infection, MRSA and urinary infections that resist treatment.
How does co-amoxiclav work?
Co-amoxiclav contains two medicines, amoxicillin and clavulanic acid. UK patient leaflets describe it as an antibiotic that works by killing the bacteria that cause infections.
MedlinePlus describes amoxicillin as a penicillin-like antibiotic that works by stopping the growth of bacteria. It describes clavulanic acid as belonging to a class of medicines called beta-lactamase inhibitors. The NHS describes co-amoxiclav as a penicillin antibiotic.
The NHS Somerset primary care guide names co-amoxiclav among the broad-spectrum antibiotics to avoid when narrower ones remain effective. The electronic medicines compendium (emc) publishes separate leaflets for different strengths and forms, and lists Augmentin tablets and suspensions as prescription-only medicines. Leaflets differ between products, so the leaflet in the pack is the reference for a particular medicine.
What are the common side effects?
The NHS lists diarrhoea, nausea and vomiting, and thrush as the common side effects of co-amoxiclav. It also says co-amoxiclav will not usually affect the ability to drive, ride a bike or use machinery.
The NHS says co-amoxiclav can sometimes cause serious side effects, although most of them are rare. MedlinePlus lists severe vomiting as a warning sign to report to the doctor. A UK formulary notes that cholestatic jaundice, a liver problem that causes yellowing of the skin, can occur during or shortly after use of co-amoxiclav.
The next section describes the serious side effects the NHS lists and the route to care for each.
Which warning signs need urgent help?
The NHS lists four serious side effects: a severe allergic reaction, skin reactions, liver problems and inflammation of the pancreas. Signs of a severe allergic reaction (anaphylaxis) include swelling of the lips, mouth, throat or tongue and fast or difficult breathing, and the NHS amoxicillin page says to call 999 for these.
Serious skin reactions can include blistering or peeling skin. Liver problems can show as pale poo with dark pee, or yellowing of the whites of the eyes or the skin. Pancreatitis, inflammation of the pancreas, causes severe pain in the stomach or back that does not go away. Some UK patient leaflets also list inflammation of the large intestine, which causes watery diarrhoea.
The NHS co-amoxiclav page says to call NHS 111 for anyone taking co-amoxiclav who thinks serious side effects may be happening.
Who needs extra care, and which medicines interact?
The NHS says co-amoxiclav is not suitable for people who have had an allergic reaction to it or another antibiotic, which can include a skin rash or swelling of the face and throat. It is also not suitable for people who have had liver problems or jaundice while taking an antibiotic.
MedlinePlus asks that any past liver problems after taking amoxicillin and clavulanic acid be reported to the doctor, who may advise against taking it again. UK patient leaflets note that some people with kidney problems may need the treatment changed.
In pregnancy the NHS says co-amoxiclav can usually be used if the doctor thinks it is needed. While breastfeeding it can usually be taken after checking with a pharmacist or doctor. The NHS names gout medicines such as allopurinol or probenecid, warfarin and methotrexate as medicines that may not mix well with it. MedlinePlus says it may decrease the effectiveness of hormonal contraceptives.
Frequently asked questions
Is co-amoxiclav the same as amoxicillin?
No. Co-amoxiclav contains amoxicillin together with a second medicine, clavulanic acid, which MedlinePlus describes as a beta-lactamase inhibitor.
What are the common side effects of co-amoxiclav?
The NHS lists diarrhoea, nausea and vomiting, and thrush as the common ones. The NHS says co-amoxiclav will not usually affect the ability to drive, ride a bike or use machinery, and that most serious side effects are rare.
Can co-amoxiclav cause liver problems?
The NHS lists liver problems among the serious side effects, with pale poo and dark pee or yellowing of the skin or whites of the eyes as signs. It is not suitable for people who have had liver problems or jaundice while taking an antibiotic. The NHS says to call NHS 111 if serious side effects are suspected.
What if the face or throat swells after taking it?
Swelling of the lips, mouth, throat or tongue, or fast or difficult breathing, may be anaphylaxis, a severe allergic reaction, and the NHS amoxicillin page says to call 999.
Can co-amoxiclav be used in pregnancy or breastfeeding?
The NHS says it can usually be used in pregnancy if the doctor thinks it is needed, and usually while breastfeeding after checking with a pharmacist or doctor.
Connected pages in detail
What each linked page on Anatomy Nexus covers, in a line, for Co-amoxiclav (Augmentin).
Conditions
- Urinary tract infection Bacterial infection of the bladder (cystitis) or, when it ascends, the kidney (pyelonephritis), usually by gut bacteria such as Escherichia coli.
Symptoms
- Rash Any change in the colour or texture of the skin.
- Nausea The unpleasant sensation of being about to vomit.
- Vomiting Forceful emptying of the stomach through the mouth, a protective reflex run by the brainstem that closes the airway.
- Abdominal pain Pain between the ribs and the pelvis.
Medications
- Amoxicillin A widely used penicillin antibiotic that kills bacteria by breaking their cell walls, prescribed for chest, ear, sinus.
- Warfarin The long-established oral anticoagulant that blocks vitamin K-dependent clotting factors.
- Allopurinol A xanthine oxidase inhibitor that lowers uric acid in the blood.
Drug classes
- Penicillins The oldest family of antibiotics and still the first choice for many chest, ear, throat, skin and dental infections: amoxicillin, co-amoxiclav.