Co-amoxiclav at a glance
Medicine class
Penicillin antibiotic combined with a beta-lactamase inhibitor
Usual role
Treatment of selected bacterial respiratory, urinary, dental, skin, bone and joint infections
Available forms
Oral tablets and suspensions, plus intravenous formulations used in clinical settings
Taking oral forms
Take with a meal; measure liquids with the supplied device
What is Co-amoxiclav used for?
Licensed uses include susceptible bacterial infections affecting the following areas. Intravenous products also cover certain severe infections and surgical prophylaxis.
Sinuses and middle ear
Lower respiratory tract
Urinary tract
Skin and soft tissue, including cellulitis, animal bites and severe dental abscess with spreading cellulitis
Bones and joints, particularly osteomyelitis
Severe ear, nose and throat, intra-abdominal and female genital infections treated intravenously
Prevention of infection associated with specified major surgical procedures using intravenous treatment
How does Co-amoxiclav work?
Amoxicillin blocks bacterial cell-wall formation, causing susceptible bacteria to break down. Clavulanic acid inhibits certain beta-lactamases that would otherwise destroy amoxicillin. It does not overcome every form of bacterial resistance.
Co-amoxiclav preparations and strengths
Oral suspension
Route: Oral
Strengths: 125 mg + 31.25 mg/5 mL, 250 mg + 62.5 mg/5 mL, 400 mg + 57 mg/5 mL
Tablet
Route: Oral
Strengths: 250 mg + 125 mg, 500 mg + 125 mg, 875 mg + 125 mg
How to take Co-amoxiclav
Follow the dispensing label and product leaflet. Take oral co-amoxiclav with a meal, swallow tablets with water and measure liquid with the supplied oral syringe or spoon rather than a kitchen teaspoon.
Shake oral suspension well before use.
Different liquid formulations are not automatically interchangeable; use the exact product and measuring device supplied.
Intravenous co-amoxiclav is prepared and administered by healthcare professionals.
Co-amoxiclav side effects
Common or expected effects
- Diarrhoea
- Feeling sick or being sick
- Thrush
Get urgent medical advice
- Immediate allergic reaction, including breathing difficulty or facial, tongue or throat swelling
- Severe skin reactions with blistering, peeling or widespread rash
- Antibiotic-associated colitis, particularly severe, persistent or bloody diarrhoea
- Hepatitis or cholestatic jaundice, which may cause yellow skin or eyes, dark urine or pale stools
- Acute pancreatitis causing severe persistent abdominal or back pain
- Convulsions, particularly with impaired renal function or excessive exposure
Co-amoxiclav in pregnancy
Penicillin antibiotics, including co-amoxiclav, can be used during pregnancy when recommended by a doctor. Available human data do not indicate increased congenital-malformation risk. It is not generally used to prevent infection following preterm premature rupture of membranes because one study reported an increased risk of neonatal necrotising enterocolitis.
Co-amoxiclav while breastfeeding
Co-amoxiclav can usually be used while breastfeeding after clinical assessment. Monitor a full-term, healthy infant for diarrhoea, thrush, rash, breathing problems or feeding changes. Seek specialist advice if the infant is premature or unwell.
Co-amoxiclav interactions
Important interactions include:
Warfarin and other oral anticoagulants
Anticoagulant effect and INR may increase, so closer monitoring may be needed when co-amoxiclav is started or stopped.
Methotrexate
Penicillins may reduce methotrexate excretion and increase toxicity risk.
Probenecid
It reduces renal secretion of amoxicillin, increasing and prolonging amoxicillin concentrations; combined use is not recommended.
Allopurinol
Concurrent use with amoxicillin may increase the likelihood of allergic skin reactions.
Common questions about Co-amoxiclav
Answers are fully visible for fast scanning and source review.
Is co-amoxiclav a penicillin antibiotic?
Yes. It contains the penicillin amoxicillin and the beta-lactamase inhibitor clavulanic acid.
Does co-amoxiclav work for viral infections?
No. It treats susceptible bacterial infections, not viral illnesses such as colds or influenza.
Can someone with a penicillin allergy take co-amoxiclav?
It is contraindicated in people with penicillin hypersensitivity and those with a previous severe immediate reaction to another beta-lactam. Assess allergy history before use.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.