Flucloxacillin
General Information
A penicillin antibiotic. Do NOT use if patient is allergic to penicillin.
For adult critical care areas only: Where using flucloxacillin by continuous Infusion see Adult Intensive Care Medication Guidelines
Formulary antimicrobial: Use in accordance with Trust guidelines
AWaRe antibiotic classification: 'Access'. Use as per guidelines.
For all information regarding contra-indications, interactions, contraception, pregnancy and breastfeeding and additional information, see BNF and Summary of Product Characteristics (SPC).
Dosage
See separate guideline for Infective Endocarditis Treatment
|
|
Oral flucloxacillin |
Intravenous flucloxacillin |
|
Standard dose |
500mg – 1g QDS |
1g – 2g QDS |
|
MSSA bacteraemia |
|
2g QDS |
|
Ambulatory treatment with elastomeric |
See cellulitis, lower or upper limb, including ambulatory care |
Obesity
Dosing should be at the upper end of recommended ranges, particularly for morbidly obese patient with severe infection, considering patient’s renal function.
Renal and hepatic impairment
Renal Impairment
|
eGFR (mL/min/1.73m2) |
flucloxacillin dose (oral or intravenous) |
|
10 or more |
Dose as in normal renal function |
|
Less than 10 |
Max 4g daily |
|
HDF/High Flux/PD |
Not dialysed. Dose as in eGFR less than 10 mL/min/1.73m2 |
Note: Doses are based on Renal Drug Database
Hepatic impairment
- Flucloxacillin is contraindicated in patients with a previous history of flucloxacillin-associated jaundice/hepatic dysfunction.
- No dose adjustment required. Use with caution.
- The risk of flucloxacillin-induced liver injury is higher in patients with hepatic dysfunction who are 50 years and over or with severe underlying disease. Hepatic events can be severe and may very rarely result in death.
- Hepatitis and cholestatic jaundice onset can be delayed by up to two months. Neither route nor dose-related.
References
- Esteve Pharmaceuticals (formerly Intrapharm Laboratories). Flucloxacillin 1000 mg powder for solution for injection or infusion summary of product characteristics. Electronic medicines compendium. Last revision of the text 5/3/26. Accessed via www.medicines.org.uk Accessed 04/11/26.
- Flamingo Pharma. Flucloxacillin Capsules 500 mg summary of product characteristics. Electronic medicines compendium. Last revision of the text 12/12/24. Accessed via www.medicines.org.uk Accessed 04/11/26.
- British National Formulary. Flucloxacillin. BNF online accessed via www.medicinescomplete.com Accessed 04/11/26.
- The Renal Drug Database. Flucloxacillin. Last updated 15/4/26. Accessed via https://renaldrugdatabase.com Accessed 04/11/26.
- Sanford Guide [online]. Flucloxacillin. Last updated 20/10/26. Accessed via https://webedition.sanfordguide.com. Accessed 04/11/26.
- GIG Cymru NHS Wales. All Wales antimicrobial dosing in extremes of body weight in adults. Last updated April 2022. Accessed via https://phw.nhs.wales/resources/all-wales-antimicrobial-dosing-in-extremes-of-body-weight-in-adults/ Accessed 04/11/26