Amoxicillin-Clavulanic Acid

Guidelines for use

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1. Spectrum of activity

Active against:

  • Gram positive aerobes: Staphylococci- methicillin-sensitive strains (MSSA), Streptococci, Enterococcus faecalis
  • Gram negative aerobes: most strains of coli, Klebsiella spp., Proteus spp.
  • Anaerobes: most oral and gut anaerobes (e.g. fragilis)

Not active against:

  • Methicillin-resistant Staphylococcus aureus (MRSA)
  • Enterococcus faecium
  • Pseudomonas aeruginosa
  • Extended spectrum beta-lactamase (ESBL) producing organisms
  • AmpC beta-lactamase producing organisms (Serratia spp., Morganella morganii, Providencia spp., Proteus spp. (not P. mirabilis), Citrobacter spp., Enterobacter spp., Hafnia spp., Pantoea spp., Klebsiella aerogenes)

2. Clinical use

Oral Formulation:

  • Upper respiratory tract infections, such as sinusitis (typically reserved for non-resolving or relapsing infection)
  • Lower respiratory tract infections
  • Polymicrobial skin and soft tissue infections
  • Urinary tract infections when polymicrobial coverage is required
  • Intra-abdominal infections

IV Formulation:

The IV formulation of amoxicillin-clavulanic acid should be used instead of piperacillin-tazobactam for treatment of polymicrobial infections where Pseudomonas aeruginosa coverage is not needed and ceftriaxone containing regimens are not sufficient, including:

  • Severe animal bite infections
  • Severe polymicrobial skin and soft tissue infections
  • Severe polymicrobial head and neck infections
  • Select intra-abdominal infection where Enterococcus coverage is required

Note: IV amoxicillin-clavulanate is MORE expensive than ceftriaxone + metronidazole

3. Inappropriate uses

Oral Formulation:

  • Treatment of severe infections that require high systemic concentrations of antibiotics

IV Formulation:

  • Infections which require coverage for Pseudomonas aeruginosa
  • Community acquired pneumonia, urinary tract infection, intra-abdominal infection (ceftriaxone-containing regimens are recommend as first-line treatment options as they are efficacious and more cost-effective)
  • Outpatient parenteral antimicrobial therapy (due to short stability)

4. Precautions

5. Adverse effects

  • Nausea, abdominal pain, vomiting, diarrhea
  • Use should be avoided if infectious mononucleosis is suspected due to the risk of developing a morbilliform rash
  • Hypersensitivity reactions including anaphylaxis
  • Hepatic events have been reported predominantly in males and elderly patients and may be associated with prolonged treatment of amoxicillin-clavulanic acid

6. Dosage

Oral Formulation:
  • 875/125 mg PO Q12H or 500/125 mg PO Q8H
IV Formulation:
  • Usual dose: 1000/200 mg IV Q8H

Renal Insufficiency

Oral Formulation:
  • Dose adjustment not required
IV Formulation:
  • > 30 mL/min: No change
  • 10-30 mL/min: 500mg/100mg IV every 8 hours
  • < 10 mL/min: 500mg/100mg IV every 12 hours
  • HD: 500mg/100mg IV every 8 hours (cleared by dialysis)

7. Administration

8. References

  1. Amoxicillin Sodium and Potassium Clavulanate Product Monograph. Sandoz Canada Inc., Canada. Date of Revision: January 31, 2020.

Last updated: November 4, 2022