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Drug dosage identifier

Amoxicillin and Clavulanic Acid

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Dose and administration 

Intravenous dose

30mg/kg/dose  (NB the dose is based on TOTAL drug not the amoxicillin component)

 Postmenstrual age (weeks)  Postnatal age (days)  Dosing interval (hrs)
 ≤ 37  Until term corrected  12
 37 to 44   0 to 6  12
 ≥ 7 days  8

Oral dose

(NB the dose is based on TOTAL drug not the amoxicillin component)

 Postnatal age (days)  Dose  Dosing interval (hrs)
 ≥ 7  30mg/kg  8


Amoxicillin+clavulanic acid should be reserved for treatment of infections where amoxicillin alone is ineffective due to inactivation by beta lactamase enzymes. It may be used to rationalise antibiotics when infants are receiving amoxicillin and require additional cover against staphylococci that would normally be provided by adding flucloxacillin.


  •  Hypersensitivity to penicillins / cephalosporins.
  • Previous history of jaundice / hepatic dysfunction associated with Augmentin (or 
amoxicillin/clavulanic acid combination).


  • Renal impairment
    • mild renal impairment : no change to dosing schedule;
    • moderate renal impairment : increase the dosing interval. Maintain adequate fluid intake, especially with IV doses, to reduce the possibility of amoxicillin crystalluria.
  • Hepatic dysfunction - monitor liver function tests
  • Cholestatic jaundice - although rarely reported in children.
  • Cytomegalovirus - increased risk of rash
  • Oral suspension - contains aspartame (source of phenylketonuria), therefore use with caution in patients with phenylketonuria.

Clinical pharmacology

The clavulanic acid component protects the amoxicillin from degradation by beta-lactamases, thus extending the spectrum of the amoxicillin. The predominant route of elimination is renal. Oral absorption is enhanced by the presence of food.

Possible adverse effects

  • Oral candida
  • Diarrhoea and vomiting, review therapy if this occurs.
  • Hepatic events - although rarely reported in children. Consult with ID service for use greater than 14 days.
  • CNS toxicity with high doses or severe renal impairment.
  • Rashes

Special considerations

  • Not suitable for intramuscular administration4
  • Monitor renal and hepatic function and FBC if on prolonged therapy.

Management of Augmentin administration



  • Amoxicillin + clavulanic acid intravenous vials 600mg: White to off-white powder for reconstitution, containing amoxicillin 500mg (as amoxicillin sodium) and clavulanic acid 100mg (as potassium clavulanate).
  • Note: There are two strengths of injection available

Oral syrup

  • Augmentin syrup 125 : the re-constituted suspension contains amoxicillin 25 mg/mL AND clavulanic acid 6.25mg/ mL(i.e. 31.25mg / mL of TOTAL drug)
  • Note: there are two strengths of oral suspension available


Intravenous and oral

  • Doses are charted on the prescription chart in mg of TOTAL drug i.e. as amoxicillin+ clavulanic acid combined. Write on the drug chart that the dose is TOTAL drug.


Slow IV Injection

  1. Reconstitute with water for injection to 60 mg/ml immediately prior to use.
  M-amoxiclav 600mg M-amoxiclav 1.2gram
Powder Space 0.5ml 0.9ml
Water to be added 9.5ml 19.1ml
Final concentration 60mg in 1ml 60mg in 1ml
  1. Shake vigorously and administer, through a PALL 0.2 micron filter, the prescribed dose by slow IV injection over 5 minutes.
  2. The reconstituted solution of 60 mg in 1ml must be administered within 20 minutes of preparation.
  3. NOT compatible with glucose 5%, glucose 10%, sodium bicarbonate, intravenous lipid emulsion, blood products, midazolam, and metronidazole.


  1. Reconstitute powder according to instructions on the bottle label.
  2. Administer each dose with food - to reduce gastrointestinal intolerance.

Nursing considerations

  • Monitor renal
  • Maintain adequate hydration



  • Vials are single - use only.
  • Store unopened vials at room temperature.
  • Use within 20 minutes of reconstitution


  • Store reconstituted suspension in the fridge until the expiry date as stated on the bottle, then discard any remaining contents.


  1. New Zealand Formulary for Children (NZFc). Amoxicillin + clavulanic acid, NZF v[59]. [2017]. Available from: (Accessed [May], [2017])
  2. BNF for Children 2016-2017. London: BMJ Group, Pharmaceutical Press and RCPCH Publications Ltd; 2016.
  3. Amoxiclav multichem® data sheet. Auckland: Multichem NZ Limited, 2016.
  4. Augmentin® data sheet. Auckland: GlaxoSmithKline NZ Limited, 2013.
  5. McEvoy G. (ed.) Handbook on Injectable Drugs 18th ed. Bethesda: American Society of Health-System Pharmacists, Inc: 2015.

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Document Control

  • Date last published: 01 July 2017
  • Document type: Drug Dosage Guideline
  • Services responsible: ADHB Pharmacy, Neonatology, Paediatric Infectious Diseases
  • Editor: Sarah Bellhouse
  • Review frequency: 2 years