Heracillin (Flucloxacillin)

Heracillin is indicated for several types of bacterial infections where flucloxacillin‑sensitive organisms are identified. It is commonly prescribed in the following clinical situations:

• Skin and soft‑tissue infections such as cellulitis, impetigo, and infected wounds.
• Bone and joint infections, including osteomyelitis and septic arthritis.
• Respiratory tract infections caused by susceptible strains, for example, community‑acquired pneumonia.
• Infections where beta‑lactamase‑producing staphylococci are suspected.
• Situations requiring oral step‑down therapy after initial intravenous treatment.

Side effects of Heracillin vary in frequency and severity. Most patients experience mild, transient reactions, while serious adverse events are rare.

Common

• Nausea or upset stomach.
• Diarrhea, sometimes mild.
• Skin rash or mild itching.
• Elevated liver enzymes (asymptomatic).
• Headache.

Serious

• Severe allergic reactions (e.g., anaphylaxis, Stevens‑Johnson syndrome).
• Hepatotoxicity presenting with jaundice or hepatitis.
• Clostridioides difficile‑associated colitis.
• Blood dyscrasias such as neutropenia or thrombocytopenia.
• Acute interstitial nephritis.

Before starting Heracillin, consider the following precautions and warnings:

• Verify patient allergy to penicillins or any beta‑lactam antibiotics.
• Use with caution in patients with a history of liver disease or elevated liver enzymes.
• Monitor renal function in patients with severe kidney impairment.
• Assess for signs of superinfection, especially during prolonged therapy.
• Avoid use in pregnant or breastfeeding women unless clearly indicated by a healthcare professional.
• Adjust dosage in elderly patients if renal or hepatic function is reduced.
• Counsel patients to complete the full prescribed course even if symptoms improve.

Heracillin may interact with other medicines, affecting efficacy or safety. Review the following interaction categories:

Avoid

• Methotrexate, which may have increased toxicity.
• Oral contraceptives, as flucloxacillin can reduce hormonal effectiveness.
• Warfarin, potentially enhancing anticoagulant effect.
• Probenecid, which can raise flucloxacillin plasma levels.

Use with caution

• Allopurinol, may increase risk of rash.
• Non‑steroidal anti‑inflammatory drugs (NSAIDs), may raise risk of kidney injury.
• Other antibiotics, especially broad‑spectrum agents, for potential additive gastrointestinal effects.
• Antacids containing aluminum or magnesium, which could affect absorption.