Fusidic acid 💊
Related Subjects:
|Staphylococcal Infections
|Osteomyelitis
|Statins
⚠️ Statin interaction: systemic fusidic acid with a statin can cause fatal rhabdomyolysis. Stop the statin during treatment and restart it at least 7 days after the last dose of fusidic acid (MHRA).
📖 About
- Narrow-spectrum, steroid-structured antibiotic active mainly against staphylococci (including many MRSA strains).
- Resistance develops rapidly when used alone systemically, so systemic courses are given in combination (e.g. with flucloxacillin or rifampicin).
- Always check the BNF for up-to-date prescribing information.
⚙️ Mode of Action
- Inhibits bacterial protein synthesis by binding elongation factor G (EF-G) on the ribosome → blocks translocation.
- Bacteriostatic (bactericidal at high concentrations).
- Good penetration into bone, joints, skin and abscesses.
🎯 Indications
- Staphylococcal infections resistant to penicillin, especially osteomyelitis, septic arthritis and prosthetic joint infection (in combination, specialist advice).
- Staphylococcal skin and soft-tissue infections when first-line agents are unsuitable.
- Topical (cream/ointment): localised impetigo only if hydrogen peroxide 1% is unsuitable (NICE NG153) - use short courses to limit resistance.
- Eye drops (1% MR): bacterial conjunctivitis.
💊 Dose (adult)
| Preparation | Dose |
|---|
| Sodium fusidate tablets | 500 mg three times daily (may double in severe infection) |
| Fusidic acid oral suspension | 750 mg three times daily (lower bioavailability than tablets) |
| Sodium fusidate IV (body weight ≥50 kg) | 500 mg three times daily |
| Sodium fusidate IV (body weight <50 kg) | 6–7 mg/kg three times daily |
| Topical cream/ointment | Apply 3–4 times daily, usually for 5–7 days |
💉 IV Administration
- Give into a central vein if possible, or a large peripheral vein over at least 2 hours (well diluted) - high risk of venospasm and thrombophlebitis.
🧪 Monitoring
- LFTs regularly with high doses, prolonged courses or hepatic impairment (jaundice is common with IV use).
🔄 Interactions
- Statins: contraindicated in combination - see warning above.
- HIV protease inhibitors (ritonavir, saquinavir): mutual ↑ levels - avoid.
- Warfarin: ↑ INR - monitor.
- Ciclosporin: may ↑ levels.
⚠️ Cautions
- Hepatic impairment or biliary disease (excreted in bile).
- Neonates (displaces bilirubin from albumin - kernicterus risk).
🚫 Contraindications
- Hypersensitivity.
- Concomitant statin therapy (systemic use).
💥 Side Effects
- GI: nausea, vomiting, diarrhoea, dyspepsia (take tablets with food).
- Hepatic: jaundice, raised LFTs, hepatitis (reversible on stopping).
- IV: thrombophlebitis, venospasm, haemolysis with rapid infusion.
- Other: rash, hypersensitivity; rarely acute kidney injury, pancytopenia.
- Topical: local irritation, contact dermatitis.
📚 References
