Clavulanate
1 medicine
Clavulanate (clavulanic acid) protects amoxicillin from bacterial enzymes and is given only combined with it, as co-amoxiclav; its own key risk is liver injury that can appear weeks after stopping.
Key facts
- Clavulanate (clavulanic acid) is a beta-lactamase inhibitor. It has no useful antibacterial effect on its own; it is combined with amoxicillin as co-amoxiclav (brand name Augmentin) to stop bacterial enzymes from destroying the amoxicillin.
- Take it with food to reduce stomach upset, at evenly spaced intervals, and finish the whole course even if you feel better early.
- Co-amoxiclav can cause cholestatic liver injury (jaundice, dark urine, itching, pale stools). This reaction can start up to several weeks after the course ends and is more common in older men and after longer treatment.
- Never take it if you have had an allergic reaction to a penicillin, or a previous liver reaction to co-amoxiclav.
- Seek urgent care for swelling of the face or throat, breathing difficulty, or a severe blistering rash.
What clavulanate treats
Clavulanate does not treat infection by itself. Combined with amoxicillin, it extends amoxicillin's reach to bacteria that produce beta-lactamase, an enzyme that would otherwise inactivate it. Co-amoxiclav is used for sinusitis, middle ear infections, chest infections, urinary tract infections, skin and soft tissue infections, animal and human bite wounds, and dental abscesses that plain amoxicillin cannot clear.
How clavulanate works
Many bacteria defend themselves by producing beta-lactamase, an enzyme that breaks open the core ring of amoxicillin and inactivates it. Clavulanate binds tightly to this enzyme and blocks it, leaving amoxicillin intact so it can kill the bacteria as intended.
Before you take it
- Do not take co-amoxiclav if you are allergic to penicillins or cephalosporins, or if you have previously had jaundice or liver problems from this combination.
- Tell your prescriber about any liver disease, glandular fever (a widespread rash can occur), and warfarin or other blood thinners, since co-amoxiclav can enhance their effect.
- It is not routinely recommended in pregnancy unless the expected benefit outweighs the risk; discuss this with your prescriber.
Side effects
Common effects include diarrhoea, nausea, rash and vaginal thrush.
Stop and seek urgent medical care for any of these:
- Yellowing of the skin or eyes, dark urine, pale stools, persistent nausea or unusual tiredness, even weeks after finishing the course.
- A severe blistering or peeling rash.
- Swelling of the face, lips or throat, or difficulty breathing.
- Severe or bloody diarrhoea.
Safety essentials
- Liver injury from co-amoxiclav is the defining risk of this combination: it can begin weeks after treatment stops, so watch for jaundice or dark urine even after you feel well. Do not restart co-amoxiclav if you have reacted this way before.
- Confirm you have no true penicillin allergy before starting; the combination is contraindicated if you do.
- Complete the full prescribed course, even once symptoms improve, so the infection clears fully and resistant bacteria are not left behind.
This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.