Co-amoxiclav – Enhanced penicillin antibiotic for resistant bacterial infections.
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What is Co-amoxiclav?
Co-amoxiclav (also known as Augmentin) is a combination antibiotic containing amoxicillin and clavulanic acid. It’s used to treat bacterial infections that are resistant to regular amoxicillin, making it a more powerful option for serious or complicated infections.
Book an online consultation if you have signs of a bacterial infection that may require antibiotic treatment. Our GPs can assess your condition and determine if Co-amoxiclav is the most appropriate antibiotic for your specific infection.
What is Co-amoxiclav used for?
- Severe respiratory tract infections
- Complicated urinary tract infections
- Skin and soft tissue infections
- Dental infections and abscesses
- Bone and joint infections
- Post-operative infection prevention
- Beta-lactamase producing bacterial infections
How does Co-amoxiclav work?
Combines amoxicillin with clavulanic acid, which protects the amoxicillin from bacterial enzymes (beta-lactamases) that would normally destroy it, making it effective against resistant bacteria.
Dosage and Administration
Adults
375-625 mg three times daily, or 1000 mg twice daily depending on severity and formulation.
Children
Dose calculated based on weight—GP will determine appropriate strength and frequency.
Important Notes
- Take with food to reduce stomach upset and improve absorption.
- Take at evenly spaced intervals (every 8 or 12 hours).
- Complete the full course even if you feel better.
- Tablets should be swallowed whole with plenty of water.
Side Effects
Common Side Effects
- Diarrhoea (more common than with amoxicillin alone)
- Nausea and vomiting
- Skin rash
- Thrush (oral or genital)
- Abdominal pain
- Indigestion
Serious Side Effects
Seek immediate medical attention if you experience:
- Clostridioides difficile-associated diarrhoea (CDAD)
- Severe liver reactions (cholestatic jaundice)
- Severe allergic reactions
- Stevens-Johnson syndrome
- Blood disorders
Important Warnings
- Do not take if you have a penicillin allergy.
- Tell your GP if you have liver problems or a history of liver reactions to antibiotics.
- More likely to cause diarrhoea than amoxicillin alone.
- May cause false-positive results in some diabetes urine tests.
- Can reduce effectiveness of oral contraceptives.
Drug Interactions
Tell your GP if you're taking any of the following medications:
- Warfarin—may enhance anticoagulant effects.
- Methotrexate—may increase methotrexate toxicity.
- Oral contraceptives—may reduce effectiveness.
- Probenecid—may increase amoxicillin levels.
- Allopurinol—increased risk of skin reactions.
Frequently Asked Questions
Why is Co-amoxiclav prescribed instead of regular amoxicillin?
Co-amoxiclav is used when bacteria are resistant to regular amoxicillin. The clavulanic acid prevents bacteria from destroying the amoxicillin.
Why does Co-amoxiclav cause more diarrhoea?
The clavulanic acid component can irritate the bowel more than amoxicillin alone, and the combination affects gut bacteria more significantly.
Can I take probiotics while on Co-amoxiclav?
Yes, probiotics may help reduce antibiotic-associated diarrhoea. Take them a few hours apart from the antibiotic dose.
What should I do if I develop severe diarrhoea?
Contact your GP immediately, especially if there's blood or mucus, as this could indicate a serious bowel infection (C. diff).
Medically Reviewed by: Mohammed Hassan - Independent Prescriber
Last Updated: 2025-01-14