U.S. Department of Health & Human Services Divider Arrow National Institutes of Health Divider Arrow NCATS


Stereochemistry ABSOLUTE
Molecular Formula C19H16ClFN3O5S.Na
Molecular Weight 475.854
Optical Activity UNSPECIFIED
Defined Stereocenters 3 / 3
E/Z Centers 0
Charge 0







Molecular Formula Na
Molecular Weight 22.98976928
Charge 1
Stereochemistry ACHIRAL
Additional Stereochemistry
Defined Stereocenters 0 / 0
E/Z Centers 0
Optical Activity NONE

Molecular Formula C19H16ClFN3O5S
Molecular Weight 452.864
Charge -1
Stereochemistry ABSOLUTE
Additional Stereochemistry
Defined Stereocenters 3 / 3
E/Z Centers 0
Optical Activity UNSPECIFIED


Flucloxacillin is an isoxazolyl penicillin of the β-lactam group of antibiotics, which exerts a bactericidal effect upon many Gram-positive organisms including β-lactamase-producing staphylococci and streptococci. While no longer used in the United States, Flucloxacillin is supplied under a variety of trade names in other countries, including Floxapen, Flopen, Staphylex. Floxapen is indicated for the treatment of infections due to sensitive Gram-positive organisms, including β-lactamase-producing staphylococci and streptococci. Typical indications including, skin and soft tissue infections; respiratory tract infections; other infections caused by floxapen-sensitive organisms, like example, osteomyelitis, urinary tract infection, septicaemia, endocarditis. Floxapen is also indicated for use as a prophylactic agent during major surgical procedures when appropriate; for example cardiothoracic and orthopaedic surgery. Flucloxacillin, by its action on the synthesis of the bacterial wall, exerts a bactericidal effect on streptococci except those of group D (Enterococcus faecalis) staphylococci. It is not active against methicillin-resistant staphylococci. There is evidence that the risk of flucloxacillin induced liver injury is increased in subjects carrying the HLA-B*5701 allele. Despite this strong association, only 1 in 500-1000 carriers will develop liver injury. Consequently, the positive predictive value of testing the HLA-B*5701 allele for liver injury is very low (0.12%) and routine screening for this allele is not recommended. Flucloxacillin diffuses well into most tissue. Specifically, active concentrations of flucloxacillin have been recovered in bones: 11.6 mg/L (compact bone) and 15.6 mg/L (spongy bone), with a mean serum level of 8.9 mg/L. Flucloxacillin diffuses in only small proportion into the cerebrospinal fluid of subjects whose meninges are not inflamed. It is also excreted in small quantities in mother's milk. In normal subjects approximately 10% of the flucloxacillin administered is metabolised to penicilloic acid. The elimination half-life of flucloxacillin is in the order of 53 minutes.

CNS Activity

Approval Year



How to calculate clearance of highly protein-bound drugs during continuous venovenous hemofiltration demonstrated with flucloxacillin.
Necrotising fasciitis in neonates: a multidisciplinary approach.
2003 Aug 22
Unilateral submandibular suppurative sialadenitis in a premature infant.
2003 Dec
[Optimalization of antibiotic policy in the Netherlands. VII. SWAB-guidelines for antimicrobial therapy in adults patients with infectious endocarditis].
2003 Dec 6
Clinicopathological case 3: pemphigus foliaceus; bullous impetigo; subcorneal pustular dermatoses.
2003 Jul
The pharmacokinetics of the interstitial space in humans.
2003 Jul 30
A systematic review and meta-analysis of treatments for impetigo.
2003 Jun
[Diagnostic image (128). A boy who refused to walk. Spondylodiscitis LIV-LV].
2003 Mar 1
Ringworm causing childhood preseptal cellulitis.
2003 May
Small colony variants of Staphylococcus aureus and pacemaker-related infection.
2003 Oct
The use of prophylactic flucloxacillin in treatment of open fractures of the distal phalanx within an accident and emergency department: a double-blind randomized placebo-controlled trial.
2003 Oct
Methicillin-resistant Staphylococcus aureus in children with cystic fibrosis: An eradication protocol.
2003 Sep
Early interventions in CF.
Is the MIC useful in deciding to treat endocarditis surgically?
2004 Apr
[Diagnostic image (185). A man with a pimple on the upper lip. Carbuncle of the upper lip].
2004 Apr 17
[Diagnostic image (202). A newborn with subfebrile temperature and skin lesions. Staphylococcal scalded skin syndrome].
2004 Aug 14
Streptococcal necrotising fasciitis from diverse strains of Streptococcus pyogenes in tropical northern Australia: case series and comparison with the literature.
2004 Dec 16
Pharmacokinetics of intravenous flucloxacillin and amoxicillin in neonatal and infant cardiopulmonary bypass surgery.
2004 Feb
Purpura fulminans due to E. coli septicemia.
2004 Feb 16
Panton-valentine leukocidin and staphyloccoccal skin infections in schoolchildren.
2004 Jan
Congenital cyanotic heart disease and headache.
2004 Jan-Feb
Acute and clinically relevant drug-induced liver injury: a population based case-control study.
2004 Jul
Effects of duplicate and screening isolates on surveillance of community and hospital antibiotic resistance.
2004 Jul
Treatment of bullous impetigo and the staphylococcal scalded skin syndrome in infants.
2004 Jun
Osteomyelitis of the accessory navicular bone in the foot. A case report.
2004 Jun
Dermoscopy of tungiasis.
2004 Jun
Imported cutaneous diphtheria, United Kingdom.
2004 Mar
[Cutaneous nocardiosis as an opportunistic infection].
2004 Mar 13
Modulation of beta-lactam resistance in Staphylococcus aureus by catechins and gallates.
2004 May
Percutaneous closure of interatrial communications in adults - prospective embolism prevention study with two- and three-dimensional echocardiography.
2004 May 19
Allogenic blood transfusion does not predispose to infection after cardiac surgery.
2004 Nov
A randomized clinical trial to compare fleroxacin-rifampicin with flucloxacillin or vancomycin for the treatment of staphylococcal infection.
2004 Nov 1
Therapeutic impact of percutaneous spinal biopsy in spinal infection.
2004 Oct
Activity of nadifloxacin (OPC-7251) and seven other antimicrobial agents against aerobic and anaerobic Gram-positive bacteria isolated from bacterial skin infections.
2004 Oct
Methicillin-resistant Staphylococcus aureus in Europe, 1999-2002.
2004 Sep
Osteomyelitis complicating pyomyositis in HIV disease.
2004 Sep
Determination of certain drugs in binary mixtures formulations by second derivative ratio spectrophotometry and LC.
2004 Sep
Investigation of microenvironmental factors influencing the longitudinal relaxation times of drugs and other compounds.
2004 Sep
Thoracic spondylitis from a mycotic (Streptococcus pneumoniae) aortic aneurysm: a case report.
2004 Sep 1
Staphylococcus aureus bacteremia, Australia.
2005 Apr
Flucloxacillin-induced aplastic anaemia and liver failure.
2005 Apr
Quantitative determination method for trace amount of penicillin contaminants in commercially available drug product by HPLC coupled with tandem mass spectrometry.
2005 Feb
Non-paracetamol drug-induced fulminant hepatic failure among adults in Scotland.
2005 Feb
An isocratic ion exchange HPLC method for the simultaneous determination of flucloxacillin and amoxicillin in a pharmaceutical formulation for injection.
2005 Feb 23
Cutaneous adverse drug reaction to oral chlorphenamine detected with patch testing.
2005 Jan
Acute osteomyelitis and septic arthritis in children.
2005 Jan-Feb
Flucloxacillin associated neutropenia in children treated for bone and joint infections.
2005 Jan-Feb
Bactericidal activity of flucloxacillin against Staphylococcus aureus in primary keratinocyte cultures of lesional and unaffected skin of patients suffering from atopic dermatitis.
2005 Mar
Flucloxacillin alone or combined with benzylpenicillin to treat lower limb cellulitis: a randomised controlled trial.
2005 May
The role of antibiotic prophylaxis in clean incised hand injuries: a prospective randomized placebo controlled double blind trial.
2005 May


Sample Use Guides

In Vivo Use Guide
Usual adult dosage (including elderly patients): Oral - 250 mg four times a day. Osteomyelitis, endocarditis - Up to 8 g daily, in divided doses six to eight hourly. Usual children's dosage: 2-10 years: half adult dose. Under 2 years: quarter adult dose.
Route of Administration: Oral
In Vitro Use Guide
Flucloxacillin showed less activity, with MICs up to 32 ug/ml against of methicillin-resistant Staphylococcus aureus.
Substance Class Chemical
by admin
on Tue Oct 22 13:06:08 UTC 2019
by admin
on Tue Oct 22 13:06:08 UTC 2019
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Created by admin on Tue Oct 22 13:06:09 UTC 2019 , Edited by admin on Tue Oct 22 13:06:09 UTC 2019
Created by admin on Tue Oct 22 13:06:09 UTC 2019 , Edited by admin on Tue Oct 22 13:06:09 UTC 2019
Created by admin on Tue Oct 22 13:06:09 UTC 2019 , Edited by admin on Tue Oct 22 13:06:09 UTC 2019
Created by admin on Tue Oct 22 13:06:09 UTC 2019 , Edited by admin on Tue Oct 22 13:06:09 UTC 2019
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