Clavulanic acid
A beta-lactamase inhibitor never given alone: it is combined with amoxicillin as co-amoxiclav against beta-lactamase-producing bacteria.
Also called clavulanate (US name, as clavulanate potassium) or co-amoxiclav (UK name of amoxicillin with clavulanic acid).
Drug card
- How it works
- Inactivating bacterial beta-lactamases so the partner penicillin survives
- Used for
- Chest infections and community-acquired pneumonia
- Sinusitis
- Middle ear infections (otitis media)
- Cellulitis, animal bites and dental abscess
- Known for
- Cholestatic jaundice
Study it as a flashcard, and it comes back before you forget it.
Mechanism of action
How does clavulanic acid work?
Clavulanic acid is a beta-lactam made by Streptomyces clavuligerus. It blocks the active site of many beta-lactamases, including the plasmid-encoded enzymes that spread resistance between bacteria, so amoxicillin is not destroyed. This extends amoxicillin to beta-lactamase-producing H. influenzae, Moraxella catarrhalis, S. aureus (not MRSA), E. coli and Klebsiella.
Like other beta-lactamase inhibitors: Beta-lactamase inhibitors are beta-lactams with almost no useful antibacterial action of their own. They bind at or near the active site of bacterial beta-lactamases and inactivate them, so a partner penicillin given with them is not broken down. Clavulanic acid and tazobactam block mainly class A enzymes; class B, C and D beta-lactamases escape clavulanic acid.
Uses
What is clavulanic acid used for?
- Chest infections and community-acquired pneumonia
- Sinusitis
- Middle ear infections (otitis media)
- Cellulitis, animal bites and dental abscess
- Cystitis and kidney infection (pyelonephritis)
- Bone and joint infections
Side effects
Side effects of clavulanic acid
- Cholestatic jaundiceKnown forSerious
- Diarrhea
- Nausea and vomiting
- Oral or vaginal thrush
- Hepatitis, sometimes weeks after the courseSerious
- Allergic reactions, including anaphylaxisSerious
- Rash, especially in glandular fever
- C. difficile colitisSerious
- Severe skin reactions (SJS, TEN, DRESS, AGEP)Serious
- Interstitial nephritisSerious
- Acute pancreatitisSerious
- Seizures, mainly with kidney impairmentSerious
Known for marks what an exam expects you to know it for.
Watch for
Cautions and what sets it apart
- Given only with amoxicillin (co-amoxiclav), so penicillin allergy rules it out.
- Past co-amoxiclav jaundice is a contraindication; liver reactions are commoner in men, older people and long courses.
- Avoid in glandular fever: the amoxicillin part often causes a widespread rash.
- Warfarin: the INR can rise, so clotting is checked more often.
Good to know: This card covers clavulanic acid as the beta-lactamase inhibitor partner in co-amoxiclav (amoxicillin/clavulanic acid). On its own it has no clinically useful antibacterial effect.
Remember it
A way to remember it
A bodyguard for the penicillin: the inhibitor takes the beta-lactamase's hit so the penicillin survives to kill.
Clavulanic acid and tazobactam are beta-lactams that tie up beta-lactamase at its active site. They do almost nothing to bacteria on their own; their job is to keep amoxicillin or piperacillin intact.
Written for biofideX
Its class
Beta-lactamase inhibitors
Other beta-lactamase inhibitors with a card:
Easily mixed up with penicillins and carbapenems.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
- Amoxicillin and clavulanate potassium tablets: label (DailyMed)
- Amoxicillin and clavulanate potassium for oral suspension 600 mg/42.9 mg per 5 mL: label (DailyMed)
- Co-amoxiclav 500 mg/125 mg film-coated tablets: SmPC (emc)
- Clavulanic Acid (NCI Thesaurus)
- Co-amoxiclav (NHS)
For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.
Antibiotics: the cell wall
Clavulanic acid is one of 12 drugs practiced together here: their classes, how they work, what they treat and what they're known for.
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