Indications
S-Fluclox is used to treat infections caused by Gram-positive organisms, including those due to penicillinase-producing staphylococci. It covers skin and soft tissue infections such as boils, abscesses, and carbuncles, as well as infected skin conditions like ulcers, eczema, acne, furunculosis, cellulitis, infected wounds, infected burns, otitis media and externa, and impetigo. It is also used for respiratory tract infections, including pneumonia, lung abscess, empyema, sinusitis, pharyngitis, tonsillitis, and quinsy. Beyond these, it treats other infections such as osteomyelitis, enteritis, endocarditis, urinary tract infection, meningitis, and septicaemia caused by organisms sensitive to S-Fluclox. It is also given as a preventive measure during major surgical procedures where appropriate, such as cardiothoracic and orthopedic surgery.
⚠️ Always consult a registered physician before taking any medicine.
Pharmacology
Flucloxacillin is active against Gram-positive organisms, including strains that produce penicillinase, though it has little effect on Gram-negative bacilli. It works by blocking formation of the bacterial cell wall. As an isoxazolyl penicillin, it combines resistance to breakdown by penicillinase with stability in stomach acid and activity against Gram-positive bacteria, making it a bactericidal antibiotic that is especially useful against penicillinase-producing staphylococci.
More specifically, Flucloxacillin disrupts the bacterial cell wall by interfering with the synthesis of peptidoglycan, the heteropolymeric structure that gives the cell wall its mechanical strength. The final step of peptidoglycan synthesis is the cross-linking of the terminal glycine residue of the pentaglycine bridge to the fourth residue (D-alanine) of the pentapeptide, a step carried out by the transpeptidase enzyme. Flucloxacillin inhibits this enzyme, so the cell wall is weakened and the bacterial cell swells and eventually ruptures. It is thought to resist bacterial penicillinase because of steric hindrance from its acyl side chain, which prevents the beta-lactam ring from being opened.
Pregnancy & Breastfeeding
Pregnancy and Breastfeeding: Flucloxacillin falls under US FDA Pregnancy Category B. There are no adequate, well-controlled studies of its use in pregnant women, and because animal studies don't always predict how humans will respond, it should only be used during pregnancy when clearly necessary. Flucloxacillin also passes into breast milk, so it should be given to breastfeeding mothers with caution.
⚠️ Talk to your doctor before taking any medicine during pregnancy or while breastfeeding.
Dosage Reference
⚠️ Reference ranges from official sources only. Consult your doctor for personalized dosing.