Amoxicillin+clavulanate (Augmentin) is an important broad spectrum agent that includes Gram negative anaerobic coverage (see below). We rely on it for a variety of complex infections, often as a second line.
Compared with amoxycillin alone, the incidence of gastrointestinal, hepatic and haematological side effects is significantly higher for amoxicillin+clavulanic acid. It may be associated with a higher risk of Stevens-Johnson syndrome, purpura and hepatitis. Superinfections with Clostridium difficile in (community or hospital) are also a significant risk.
Common circumstances of misuse and recommended (eTG) alternative approaches:
| Syndrome | Indicated first line alternative to amoxicillin+clavulanate |
| Otitis media
Acute sinusitis |
Wait and see delayed script approach
Amoxycillin. See also. |
| Acute pharyngitis | Wait and see delayed script approach +/- throat swab to confirm group A strep in child
Phenoxymethylpenicillin. See also. |
| Acute on chronic obstructive pulmonary disease (COPD) | Symptomatic management dependent on asthma presence etc.
Doxycycline OR amoxycillin short course– reserve for severe exacerbations |
| Acute bronchitis or post viral cough syndrome | Avoid antibiotic therapy– post viral cough lasts 2-3 weeks usually! |
| Cellulitis | Flucloxacillin or dicloxacillin
Cotrimoxazole or doxycycline if MRSA implicated |
| Skin/Soft tissue infection (boils) | Incision and drainage. See also. |
| Acute uncomplicated diverticulitis | Avoid antibiotic therapy |
| Urinary tract infection
|
Use trimethoprim or cephalexin due to lower side effects
Direct therapy against demonstrated pathogen |
Comparative spectra – what does the clavulanate add in fact?
| Category | Bacterial species | Amoxycillin
% susc |
Amox+clav
% susc |
Relevance |
| Gram negative | E. coli
Klebsiella pneumoniae |
~40%
0% |
~ 80%
~ 80% |
Treatment of UTI / intra-abdominal infections |
| Enterobacter-like species* | 0%
|
=
|
No advantage
|
|
| Bacteroides group (Gram negative anaerobes) | < 20%
|
~ 95%
|
Intra-abdominal infections, diabetic foot infection | |
| Haemophilus influenzae
Moraxella catarrhalis |
70%
< 5% |
~ 95%
100 % |
Reserved for second line or treatment failure.
(These organisms frequently represent colonisers in resp. tract) |
|
| Pasteurella multocida | 100% | = | No advantage; anaerobic cover valuable for animal bites however | |
| Gram positive | Streptococcus pneumoniae (non CNS infection) | 90%
|
=
|
No advantage
|
| Streptococcus pyogenes (group A) and other beta haemolytic streptococci | 100%
|
=
|
No advantage
|
|
| Staphylococcus aureus (MSSA)
|
20%
|
100%
|
NOT drug of choice – use dicloxacillin or cephalexin | |
| Staphylococcus aureus (MRSA)
|
0%
|
=
|
No advantage
|
|
| Enterococcus faecalis
Enterococcus faecium |
~ 95%
0 % |
=
= |
No advantage
|
|
| Peptostreptococci and other Gram positive anaerobes | 100%
|
=
|
No advantage
|
* Includes Enterobacter cloacae, Serratia species, Citrobacter freundii, Morganella morganii and related species
References
- Australian Therapeutic Guidelines: Antibiotic, edition 15, 2014
- Salvo F et al. Adverse drug reactions related to amoxicillin alone and in association with clavulanic acid: data from spontaneous reporting in Italy. J Antimicrob Chemother. 2007 Jul;60(1):121-6.
AIMED - Let's talk about antibiotics 
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