Raw research findings for this medication. Mostly single studies, not curated or confirmed robust.
Flucloxacillin is a penicillin antibiotic designed to resist the penicillinase enzyme that many staphylococci make. It is used widely in the UK, Europe and Australia for skin, soft tissue, bone and other infections caused by Staphylococcus aureus; in the US the closely related dicloxacillin is used instead. It is sold as Floxapen, among other names.
Flucloxacillin can rarely cause a delayed liver injury (cholestatic hepatitis), and a genome-wide study found that carriers of HLA-B*57:01, the same immune-system gene version that matters for abacavir, have around 80 times the risk. The injury remains rare even in carriers. DPWG has published a guideline on HLA-B*57:01 and flucloxacillin. Few other genes have been studied.
Clinical guidelines that name a gene for Flucloxacillin. They sort people into groups by the gene copies they carry.
DPWG guideline: HLA-B. *57:01 positive.
Every published finding on gene variants and Flucloxacillin. Upload your DNA file to see which of these rows apply to you.
PharmGKB weighs all studies of a variant and rates how strong the evidence is, from 1A (strongest) to 4.
HLA-B HLA-B*57:01: Level 1A · replicated. Toxicity: Drug-induced liver injury. 1.
NR1I2 rs3814055: Level 3. Toxicity: Toxic liver disease. 1.
Study findings and evidence levels: PharmGKB (CC BY-SA 4.0). Guidelines: CPIC and DPWG, as bundled in PharmCAT. Most studies were done mainly in people of European ancestry.
More drugs from the same category
Not a prescribing recommendation. This page is educational information about pharmacogenomic research and clinical guidelines - it is not medical or dosing advice, and not a prediction of how any medication will work for you. Never start, stop, or change a medication or dose based on it; talk to your doctor or pharmacist, who can order clinical-grade testing if appropriate.
Content updated September 2026.
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