PENFLOX GR SUSPENSION

Indications

• Skin and soft tissue infections
• Respiratory tract infections
• Bone and joint infections (osteomyelitis)
• Endocarditis prophylaxis
• Infections caused by penicillinase-producing Staphylococcus aureus

Dosage

Children: Refer to the BNF for Children for pediatric dosing information based on age and weight.

Adults: Refer to the BNF for specific dosing guidelines based on the type and severity of the infection.

Mechanism of action

Flucoxacillin exerts its bactericidal action by binding to penicillin-binding proteins (PBPs) located on the bacterial cell membrane. This binding inhibits the synthesis of bacterial cell walls, leading to cell lysis and death. The drug is particularly effective against Staphylococcus aureus and other penicillinase-producing bacteria, which have developed resistance to other penicillins.

Pharmacodynamics

Flucoxacillin displays time-dependent bactericidal activity, meaning its effectiveness is related to the duration of time that the drug concentration remains above the minimum inhibitory concentration (MIC) for the target pathogens. Its spectrum of activity primarily includes gram-positive cocci, especially Staphylococcus aureus, Streptococcus pneumoniae, and some strains of Streptococcus pyogenes.

Pharmacokinetics

After oral administration, flucoxacillin is rapidly absorbed, with peak plasma concentrations occurring within 1-2 hours. It has a bioavailability of approximately 50-70%. The drug is extensively protein bound, primarily to albumin. Flucoxacillin is metabolized in the liver and excreted predominantly through the kidneys. The elimination half-life ranges from 0.9 to 1.5 hours, necessitating frequent dosing to maintain effective therapeutic levels.

Contra-indications

• Hypersensitivity to flucloxacillin or any other penicillin
• History of severe allergic reactions (e.g. anaphylaxis) to beta-lactam antibiotics

Adverse effects

• Nausea
• Vomiting
• Diarrhea
• Rash
• Urticaria
• Elevated liver enzymes
• Hepatotoxicity
• Anaphylactic reactions
• Superinfection

Interactions

• May reduce the effectiveness of oral contraceptives
• Probenecid can increase the serum concentrations of flucloxacillin
• May have interactions with anticoagulants (e.g. warfarin) due to alteration in gut flora

Precautions

• Caution in patients with liver impairment
• Use with caution in patients with renal impairment
• Monitor hepatic function during prolonged therapy
• Consider the risk of Clostridium difficile-associated diarrhea

Pregnancy

Flucloxacillin is generally considered safe to use during pregnancy, but should be used only if clearly needed.

Breast-feeding

Flucloxacillin is excreted in breast milk in small amounts, but is considered compatible with breastfeeding.

Storage

Store below 25 degrees Celsius. Protect from light. After reconstitution, store in a refrigerator and use within the recommended time frame.

Formulations

• Capsules
• Oral suspension
• Injection