Drug reference

Flucloxacillin

Penicillin · Antibiotic

Also known as Flucloxacillin sodium

PenicillinAntibiotic

CDSCO approved

EXCRETION

—

not curated

INTERACTIONS

1 major

SEVERE in our sources

PREGNANCY

—

not curated

Top interactions

ParacetamolSevereDatabase

Mechanism

Flucloxacillin is an isoxazolyl penicillin that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs) and blocking transpeptidation of peptidoglycan. The isoxazolyl side chain provides steric protection of the beta-lactam ring from hydrolysis by staphylococcal penicillinases, conferring narrow-spectrum activity primarily against penicillinase-producing Staphylococcus aureus. It is associated with a pharmacogenomic risk of drug-induced liver injury linked to the HLA-B*57:01 allele.

Indications

Endocarditis (native valve) caused by staphylococciEndocarditis (prosthetic valve) caused by staphylococciMild infection (e.g., skin and soft tissue infections)Moderate or severe infection (e.g., skin and soft tissue infections)Otitis externa (in absence of penicillin allergy)Mixed infections involving beta-lactamase-producing staphylococci (as Co-fluampicil)Severe mixed infections involving beta-lactamase-producing staphylococci (as Co-fluampicil)

Dosing

Hepatic adjustment: Use with caution in patients with hepatic impairment; increased risk of cholestatic jaundice and hepatitis with increasing age and administration for more than 2 weeks.

Contraindications

Penicillin allergy
History of hepatic dysfunction associated with flucloxacillin

Side effects

Common

Gastrointestinal side effects (e.g., diarrhea)

Serious

Cholestatic jaundice
Hepatitis
Erythematous rashes (increased risk in acute lymphocytic leukaemia and chronic lymphocytic leukaemia)
Hypersensitivity reactions (rash to anaphylaxis)
Serum sickness
Stevens-Johnson syndrome
Nephropathy
Hematologic reactions (neutropenia, prolonged use)
Neurotoxicity (seizure, high doses, renal impairment)

Drug interactions

Paracetamol

Severe

Database

Increased paracetamol levels, severe metabolic acidosis, high anion gap.

Avoid co-administration. If unavoidable, monitor closely for signs of toxicity and metabolic acidosis. Adjust paracetamol dose or consider alternative analgesics.