sodium fusidate: clinical use

Prescribing considerations

• Confirm that the suspected or proven pathogen is susceptible; extended or recurrent use may select resistance.
• For severe or deep-seated infection, the tablet SmPC states that concurrent appropriate antistaphylococcal therapy should generally be considered.
• Avoid systemic treatment where gastrointestinal absorption is unpredictable; the selected tablet SmPC identifies intravenous treatment as appropriate in that setting.
• Assess liver or biliary disease, potentially hepatotoxic medicines, statin use, anticoagulation and HIV protease inhibitors before systemic prescribing.
• Use particular caution in neonates because displacement of bilirubin from albumin creates a theoretical kernicterus risk.

Contraindications and cautions

• Hypersensitivity to sodium fusidate, fusidic acid or a formulation excipient.
• Systemic sodium fusidate must not be co-administered with statins.

Monitoring

• Monitor liver function during systemic treatment in hepatic dysfunction or when potentially hepatotoxic medicines are used.
• Closely monitor anticoagulation when systemic sodium fusidate is started or stopped in a patient taking an oral anticoagulant.
• Investigate muscle pain, weakness or tenderness promptly, particularly where statin exposure is relevant.
• Review new rash promptly and discontinue systemic treatment if a serious cutaneous reaction is suspected.

Clinical pharmacology

Fusidic acid binds ribosome-associated elongation factor G and inhibits bacterial translation. It has strong antistaphylococcal activity and penetrates tissues including bone and necrotic tissue; systemic elimination is mainly biliary, with little urinary excretion.

Formulation and product differences

• The ointment is a cutaneous preparation containing lanolin, cetyl alcohol and butylhydroxytoluene, which may cause local reactions; its paraffin-containing residue creates a fabric fire hazard.
• The tablets are film-coated, contain lactose and produce systemic exposure with clinically important hepatic, muscular and interaction risks.
• Topical systemic absorption is considered negligible, so systemic medicine interactions are unlikely with the ointment.