Flucloxacillin Continuous Intravenous Infusion for Suspected/ Confirmed Staphylococcus Aureus Infective Endocarditis


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A guideline is intended to assist healthcare professionals in the choice of disease-specific treatments.

Clinical judgement should be exercised on the applicability of any guideline, influenced by individual patient characteristics. Clinicians should be mindful of the potential for harmful polypharmacy and increased susceptibility to adverse drug reactions in patients with multiple morbidities or frailty.

If, after discussion with the patient or carer, there are good reasons for not following a guideline, it is good practice to record these and communicate them to others involved in the care of the patient.

Background and Information

Flucloxacillin is a beta-lactam antibiotic and the treatment choice for suspected or confirmed Staphylococcus aureus infective endocarditis.  Clinical efficacy of beta-lactam antibiotics corresponds with time (T) the free drug exceeds the minimum inhibitory concentration (MIC) of the organism (T > MIC).  Administration of flucloxacillin by continuous infusion may therefore be associated with better clinical outcomes when compared with intermittent infusions especially in critically ill patients.  This method of administration also reduces nursing time spent preparing and administering this antibiotic, reduces the risk of missed doses and minimises the interruption for patients during unsociable hours (midnight – 6am).

If considering continuous infusion flucloxacillin please ensure:

  • intravenous access is available 24 hours/ day
  • infusion pump is available 24 hours/ day
  • patient is not leaving the ward for extended periods of time
  • renal function; Creatinine Clearance ≥ 30 ml/min

Contraindications include:

  • history of true beta-lactam allergy or any excipients
  • renal function; Creatinine Clearance < 30 ml/min

Dosing Information

Loading dose: 


Loading Dose

If patient has received any flucloxacillin within the previous 4 hours

No loading dose required

If patient has NOT received any flucloxacillin within the previous 4 hours

Intravenous infusion 2000 mg over 30 minutes 


Maintenance dose:

Start immediately after loading dose or within


 hours of previous flucloxacillin dose.

Actual body weight

Dose amount and duration of intravenous

Total daily dose infusion

< 85 kg

4 g over 12 hours                                                   8 g in 24 hours

≥ 85 kg

6 g over 12 hours                                                   12 g in 24 hours

Instructions for Preparation and Administration


Dissolve the contents of 500 mg vials in 5 – 10 ml water for injection Dissolve the contents of 1 g vials in 15 – 20 ml water for injection

Dilution and suitable diluents:

Following reconstitution of the required number of vial(s), dilute the required dose with sodium chloride 0.9 %.  Please see the recommended infusion volumes below:

Flucloxacillin dose

Infusion volume (sodium chloride 0.9 %)

4 g

250 ml

6 g

500 ml



  1. Adult Intravenous Medicine Monographs. Available from https://medusa.wales.nhs.uk (accessed November 2021).
  2. Gould FK et al. Guidelines for the diagnosis and antibiotic treatment of endocarditis in adults: a report of the Working Party of the British Society for Antimicrobial Chemotherapy.  Journal of Antimicrobial Chemotherapy, 2012; 67: 269 – 289.
  3. Leder K et al. The Clinical Efficacy of Continuous-Infusion Flucloxacillin in Serious Staphylococcal Sepsis.  Journal of Antimicrobial Chemotherapy, 1999; 43: 113 – 118.
  4. South Eastern Sydney Local Health District. Administration of antibiotics by prolonged or continuous infusion in the inpatient setting, Apr 2021.  Available from https://www.seslhd.health.nsw.gov.au/sites/default/files/documents/SESLHDP R%20687.pdf (accessed November 2021).

Last reviewed: 16 November 2021

Next review: 30 November 2024

Author(s): Ysobel Gourley

Version: 1

Author Email(s): [email protected]

Approved By: Antimicrobial Utilisation Committee

Document Id: 963