FLOXMED ORAL SOLUTION

Indications

• Bacterial infections due to beta-lactamase-producing staphylococci
• Cellulitis
• Endocarditis (in combination with other antibiotics)
• Osteomyelitis
• Impetigo
• Severe infections in cystic fibrosis patients

Dosage

Children: For neonates up to 7 days

Adults: The usual adult dosage for severe infections is 1 g every 6 hours, with a maximum of 4 g per day. For specific conditions, such as Staphylococcal infections, the dose may vary; consult the BNF for detailed guidance.

Mechanism of action

Flucloxacillin binds to specific penicillin-binding proteins (PBPs) within the bacterial cell wall, inhibiting the final stages of cell wall synthesis. This action leads to cell lysis, facilitated by bacterial autolytic enzymes. It may also interfere with autolysin inhibitors, enhancing its bactericidal effect.

Pharmacodynamics

As a beta-lactam antibiotic, flucloxacillin exhibits bactericidal activity, primarily against gram-positive bacteria, including Staphylococcus aureus. It is effective against both aerobic and anaerobic bacteria, and its activity results from the inhibition of peptidoglycan synthesis in the bacterial cell wall. Flucloxacillin demonstrates resistance to hydrolysis by certain beta-lactamases, allowing it to treat infections caused by resistant strains effectively.

Pharmacokinetics

Flucloxacillin is absorbed well when administered orally, with peak plasma concentrations typically occurring 1-2 hours post-dose. It is distributed widely in body tissues and fluids, including bone and bile. The drug is primarily excreted via the kidneys, with around 70-90% of an administered dose excreted as unchanged drug in the urine. Its half-life is approximately 0.5 to 1 hour, necessitating multiple daily doses for effective treatment.

Adverse effects

• Vulvo-vaginal fungal infection
• Dizziness
• Fatigue
• Gastrointestinal discomfort
• Gastrointestinal disorders
• Headache
• Oral ulceration
• Vertigo

Interactions

• Refer to Appendix 1: penicillins (severe infection)

Precautions

• Avoid in acute porphyrias
• Monitor liver and renal function tests required in long-term use

Pregnancy

Not known to be harmful, but the manufacturer advises avoidance.

Breast-feeding

Trace amount in milk, but appropriate to use.

Storage

Store in a cool, dry place away from direct sunlight.

Formulations

• Tablets
• Injectable solution

Mechanism of action

By binding to specific penicillin-binding proteins (PBPs) located inside the bacterial cell wall, flucloxacillin inhibits the third and last stage of bacterial cell wall synthesis. Cell lysis is then mediated by bacterial cell wall autolytic enzymes such as autolysins; it is possible that flucloxacillin interferes with an autolysin inhibitor.

Pharmacodynamics

Flucloxacillin is a penicillin beta-lactam antibiotic used in the treatment of bacterial infections caused by susceptible, usually gram-positive, organisms. The name "penicillin" can either refer to several variants of penicillin available, or to the group of antibiotics derived from the penicillins. Flucloxacillin has <i>in vitro</i> activity against gram-positive and gram-negative aerobic and anaerobic bacteria. The bactericidal activity of Flucloxacillin results from the inhibition of cell wall synthesis and is mediated through flucloxacillin binding to penicillin binding proteins (PBPs). Flucloxacillin is stable against hydrolysis by a variety of beta-lactamases, including penicillinases, and cephalosporinases and extended spectrum beta-lactamases.