What is Flucloxacillin?
Flucloxacillin, also known as floxacillin, is a narrow-spectrum beta-lactam antibiotic belonging to the penicillin family. It is part of a subgroup of semi-synthetic penicillins developed to be resistant to degradation by bacterial penicillinase enzymes. These enzymes are produced by many bacteria, such as Staphylococcus aureus, to counteract the effects of earlier penicillin antibiotics. Flucloxacillin's resistance to these enzymes makes it a valuable tool against infections caused by penicillinase-producing staphylococci. However, it is not effective against the more resistant form, Methicillin-resistant Staphylococcus aureus (MRSA). Flucloxacillin can be administered orally as capsules or liquid, or by injection for more severe infections.
How Does Flucloxacillin Work?
Like other beta-lactam antibiotics, flucloxacillin works by inhibiting the synthesis of the bacterial cell wall. It does this by binding to specific proteins inside the bacteria, known as penicillin-binding proteins (PBPs). This binding interferes with the cross-linkage of peptidoglycan polymer chains, a crucial component of the cell wall in Gram-positive bacteria. This leads to the disruption of the cell wall, causing the bacteria to burst and die, a process called cell lysis. Its specific structure allows it to evade the destructive action of penicillinase enzymes, ensuring it can effectively target susceptible bacteria.
Primary Sicknesses Flucloxacillin Cures
Flucloxacillin is primarily used for infections caused by susceptible Gram-positive bacteria, most notably Staphylococcus aureus.
Skin and Soft Tissue Infections
Flucloxacillin is a first-line treatment for a variety of skin and soft tissue infections, which are commonly caused by staphylococcal and streptococcal bacteria. This includes:
- Cellulitis: A common and potentially serious bacterial skin infection that causes redness, swelling, and pain in the infected area.
- Impetigo: A highly contagious skin infection that mostly affects infants and young children, causing red sores on the face.
- Boils, Abscesses, and Carbuncles: Localized infections and collections of pus within the skin.
- Infected Wounds and Burns: Used to treat infections that can develop in cuts, wounds, and burns.
- Infected Skin Conditions: Treatment for infections secondary to conditions like eczema, ulcers, or scabies.
Bone and Joint Infections
In more severe cases, flucloxacillin is used to treat deep-seated infections that have penetrated bone and joint tissues.
- Osteomyelitis: An infection of the bone. While flucloxacillin may not penetrate bone tissue as efficiently as other antibiotics, it is effective and widely used for this condition.
- Septic Arthritis: An infection of a joint, often caused by Staphylococcus aureus, which may require intravenous flucloxacillin.
Ear and Throat Infections
- External Ear Infections (Otitis externa): An infection that affects the outer ear canal.
- Middle Ear Infections (Otitis media): May be used, particularly if staphylococcal infection is suspected.
- Throat Infections: Can be used for conditions like pharyngitis and tonsillitis.
Other Severe Infections
Flucloxacillin may also be used, often in combination with other antibiotics, to treat more serious systemic infections.
- Pneumonia: A lung infection, sometimes treated with flucloxacillin, particularly if staphylococcal origin is suspected.
- Endocarditis: An infection of the heart's inner lining, requiring high-dose flucloxacillin, sometimes in combination with other drugs.
- Septicaemia: A severe bloodstream infection caused by bacteria.
- Surgical Prophylaxis: Used before major surgery, particularly heart, lung, or orthopaedic surgery, to prevent staphylococcal infections.
Comparison of Flucloxacillin with Other Antibiotics
Different antibiotics are prescribed depending on the type of bacteria causing an infection and the location and severity of the infection. Here's how flucloxacillin compares to some other common antibiotics.
| Feature | Flucloxacillin | Cephalexin | Amoxicillin + Clavulanic Acid (Co-amoxiclav) |
|---|---|---|---|
| Drug Class | Narrow-spectrum penicillin | First-generation cephalosporin | Broad-spectrum penicillin |
| Primary Use | Staphylococcal and some streptococcal infections | Staphylococcal and streptococcal skin infections, urinary tract infections | A wide range of bacterial infections, including respiratory and urinary tract |
| Spectrum | Narrow. Effective against Gram-positive, especially penicillinase-producing staphylococci. | Broad. Effective against a variety of Gram-positive and some Gram-negative bacteria. | Broad. Clavulanic acid helps overcome bacterial resistance to amoxicillin. |
| MRSA Effectiveness | No, ineffective | No, ineffective against MRSA | No, generally ineffective against MRSA |
| Mechanism | Inhibits cell wall synthesis; resistant to penicillinase. | Inhibits cell wall synthesis, but different protein-binding affinity. | Amoxicillin inhibits cell wall synthesis, while clavulanic acid inhibits beta-lactamase. |
Important Considerations and Contraindications
While generally safe, there are important factors to consider before taking flucloxacillin.
- Penicillin Allergy: Flucloxacillin should not be used in anyone with a known allergy to penicillin or other beta-lactam antibiotics.
- Liver Function: It should be used with caution in patients with a history of liver problems or who are over 50. Severe, and in very rare cases fatal, liver problems have been reported.
- Pregnancy and Breastfeeding: Flucloxacillin is generally considered safe during pregnancy and breastfeeding, but a doctor should always be consulted.
- Drug Interactions: Caution is advised when taking paracetamol concomitantly, especially in at-risk patients, due to the increased risk of high anion gap metabolic acidosis (HAGMA).
Conclusion
Flucloxacillin is a highly effective, narrow-spectrum antibiotic used to treat a wide array of infections caused by susceptible Gram-positive bacteria. Its primary applications lie in skin and soft tissue infections, though it is also crucial for more serious conditions like osteomyelitis and endocarditis. Its ability to resist penicillinase makes it particularly valuable against staphylococcal infections. However, it is ineffective against MRSA, and like all medication, it comes with important considerations, including the risk of liver issues and interactions with other drugs. As with any antibiotic, a full course should be completed as prescribed to ensure the infection is fully eradicated.
