Meds and you

Updated 11 February 2013


Co-Amoxiclav is an antibiotic combination consisting of amoxicillin, a penicillin antibiotic, and clavulanic acid.


(Also known as Co-Amoxyclav)

Co-Amoxiclav is the active ingredient of Adco-Amoclav, Amoclan, AugMaxcil, Augmentin, Austell-Co-Amoxiclav, Bio-Amoksiklav, Clamentin, Curam, Forcid, Ranclav and Sandox-Co-Amoxyclav.

General Information

Co-Amoxiclav is an antibiotic combination consisting of amoxicillin, a penicillin antibiotic, and clavulanic acid, an antibiotic substance to protect the antibiotic against resistance. It is prescribed for the treatment of a wide range of bacterial infections caused by susceptible organisms including middle ear infections, upper and lower respiratory tract infections, dental abscess, skin and soft tissue infections and gonorrhoea. It is also used to prevent bacterial growth developing inside the heart in those who are at risk of such infection during certain surgical procedures. Co-Amoxiclav is furthermore used along with other medication - often another antibiotic and a drug to reduce stomach acid secretion - to treat H. pylori, a cause of stomach ulcers.

Co-Amoxiclav can cause minor stomach upsets and a blotchy skin rash, a common unwanted effect, which is not necessarily an indication of an allergic reaction. Should you develop a skin rash, you should however consult your doctor to rule out the possibility of allergy. A penicillin allergy may lead to fever, swelling of the mouth and tongue, itching and associated breathing difficulties.

Antibiotic resistance - when a bacterium develops the ability to defend itself against the effect of an antibiotic – may occur with Co-Amoxiclav. This mostly happens when patients do not complete prescribed antibiotic courses, allowing the bacteria to recover from treatment, and the use of antibiotics for non-bacterial infections such as cold and flu. Co-Amoxiclav is not effective in treating viral infections.

Oral contraceptives may not be as effective as usual while taking Co-Amoxiclav - other methods of contraception are advised to avoid unplanned pregnancy.

How does Co-Amoxiclav work?

Co-Amoxiclav functions by changing the structure of the bacterial cell wall, allowing fluid to penetrate into the cell. As a result the bacterial cell literally ruptures.

Clavulanic acid is a competitive inhibitor of ß-lactamase, meaning that it "tricks" the bacteria into binding to it instead of the "real" antibiotic, thus allowing the antibiotic to overcome resistance. Despite this, some bacterial strains have emerged that are resistant to even such combinations.

Fast facts

Drug schedule: Schedule 4

Available as: Co-Amoxiclav is available as tablets, oral suspension and injection

What does it do? Co-Amoxiclav is an antibiotic.

Overdose risk: Low

Dependence risk: Low

Is Co-Amoxiclav available as a generic? Yes

Is Co-Amoxiclav available on prescription only? Yes

User information

Onset of effect: Rapid - within 2 hours

Duration of action: Up to 8 hours

Dietary advice: Co-Amoxiclav can be taken with or without food. Taking it with a meal may however minimise stomach irritation, diarrhoea and nausea.

Stopping this medicine: Complete the full course as prescribed by your doctor, even if you feel better within a few days. Premature discontinuation may cause symptoms to recur, or cause bacterial resistance.

Prolonged use: Co-Amoxiclav is generally given as short courses only - Prolonged use may increase the risk of a medicine-resistant infection.

Special precautions

Consult your doctor before using this drug if:

  • you are allergic to either penicillin or cephalosporins antibiotics, as there is a

possibility that you may be allergic to Co-Amoxiclav as well

  • you have kidney or liver disease
  • you have inflammatory bowel disease or ulcerative colitis
  • you have any allergies
  • you have glandular fever
  • you have leukaemia
  • you are taking other medications.

Pregnancy: This medication is considered safe. You should however still consult your doctor before use.

Breastfeeding: Avoid. This medication is passed through breast milk and may affect your baby adversely. Consult your doctor before use.

Porphyria: This medication is safe to use.

Infants and children: This medication is safe for use in children at the recommended dose.

Elderly: No special precautions need to be taken.

Driving and hazardous work: No special precautions need to be taken.

Alcohol: No special precautions need to be taken.

Possible side effects

Side effect


Consult your doctor



Only if severe

In all cases

Mild diarrhoea



Nausea / vomiting






White patches on tongue / vaginal discharge / itch



Skin rash / itch






Swollen mouth / tongue






Unusual bruising






Dizziness / fainting




Drug interactions:


Increased risk of skin rash


May affect the efficacy of Co-Amoxiclav. Take at least 2 hours apart


Reduce the efficacy of Co-Amoxiclav

Oral contraceptives

Possible reduced contraceptive efficacy. Another form of contraceptive is advised.


Increased risk of Co-Amoxiclav toxicity


Possible reduced Co-Amoxiclav efficacy


Increased risk of Warfarin toxicity

Overdose action

A small overdose is no cause for concern. In case of intentional large overdose, seek emergency medical attention.

Recommended dosage

Adults, oral: 375 mg (250 mg amoxicillin and 125 mg clavulanic acid) 3 times a day. The amoxicillin component may be increased to 625 mg every 8 hours, or 1 g every 12 hours.

Children: Co-Amoxiclav is prescribed according to the dose for amoxicillin: Children under 20 kg: 10-25 mg/kg 8 hourly; Children over 20 kg: As for adults.


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