Flucloxacillin
Drug class: β-Lactam Antibiotics; Beta-lactam antibiotics belonging to the class of the penicillin family.
Flucloxacillin（中文：氟氯西林）
Common Strengths[edit]
- Capsules: 250 mg and 500 mg.
- Oral Solution: 125 mg/5 mL and 250 mg/5 mL.
Drug Usages[edit]
Flucloxacillin is a narrow-spectrum antibiotic belonging to the penicillin class, specifically designed to combat infections caused by penicillinase-producing staphylococci and other Gram-positive organisms.
Flucloxacillin is primarily used to treat:
- Skin and soft tissue infections (e.g., cellulitis, boils, abscesses).
- Bone infections (osteomyelitis).
- Respiratory tract infections (e.g., pneumonia).
- Infections of the ear, nose, and throat.
Mechanism of Action[edit]
Flucloxacillin works by inhibiting bacterial cell wall synthesis, leading to cell lysis and death. It binds to penicillin-binding proteins (PBPs), disrupting the formation of peptidoglycan, an essential component of bacterial cell walls.
Route of Administration[edit]
- Oral (capsules or solution).
Dosages[edit]
- Adults:
- Commonly 500 mg four times daily for mild to moderate infections.
- Severe infections may require up to 8 g daily in divided doses.
- Children:
- 25-50 mg/kg/day in divided doses (for severe infections, up to 100 mg/kg/day).
- Renal Dosing:
- Generally, no dose adjustment is needed for mild to moderate renal impairment.
- For severe renal impairment (eGFR <10 mL/min), consider reducing the dose or extending the dosing interval.
Side Effects[edit]
| Frequency | Adverse reactions |
|---|---|
| Common Side Effects | Nausea |
| Vomiting | |
| Diarrhea | |
| Abdominal pain | |
| Rash | |
| Serious Side Effects | Allergic reactions (anaphylaxis) |
| Liver damage (jaundice) | |
| Severe diarrhea (possibly bloody) | |
| Interstitial nephritis. |
Pharmacokinetics[edit]
- Onset of Action: within 1 hour after oral administration.
- Duration: Approximately 6-8 hours for therapeutic effects.
- Half-life: About 53 minutes in healthy individuals; prolonged in cases of renal impairment.
Drug Precautions[edit]
Pregnancy
Generally considered safe, but consult a healthcare provider.
Breastfeeding
Minimal transfer to breast milk; usually safe but should be monitored.
Children and Elderly
- Risk of Hyperbilirubinemia: Special caution is advised in newborns, as flucloxacillin can displace bilirubin from plasma protein binding sites, increasing the risk of kernicterus, particularly in jaundiced infants
- Elderly: Increased Risk of Adverse Effects due to factors such as polypharmacy and altered pharmacokinetics. They may experience more significant side effects from flucloxacillin, including hepatic dysfunction and allergic reactions.
Monitoring Items
Liver function tests, renal function tests, and signs of allergic reactions.
Drug Interactions:
- Flucloxacillin and Paracetamol (Acetaminophen)
- Risk of Pyroglutamic Acidosis: Concurrent use of flucloxacillin and paracetamol has been associated with a rare but serious condition known as pyroglutamic acidosis (PGA), which can lead to high anion gap metabolic acidosis. This interaction is particularly concerning in patients with risk factors such as advanced age, renal impairment, malnutrition, or sepsis. Monitoring for signs of metabolic acidosis is recommended when these drugs are used together.
- Flucloxacillin and Warfarin
- Increased Warfarin Requirements: flucloxacillin may increase the dose of warfarin needed to maintain therapeutic levels.
- Enzyme Induction: Flucloxacillin has been shown to induce certain liver enzymes (specifically CYP3A4), which can alter the metabolism of other drugs.
Clinical Recommendations
- Monitoring: Regular monitoring of renal function and metabolic status is advised for patients receiving both flucloxacillin and paracetamol, especially those with pre-existing risk factors.
- INR Checks: Patients on warfarin should have their INR levels checked frequently during flucloxacillin therapy to avoid complications related to anticoagulation.
- Patient Education: It is essential to educate patients about the signs of potential adverse effects from these interactions, particularly symptoms related to metabolic acidosis or changes in bleeding tendency.
FAQ[edit]
How Should I Take the Tablet?
Take flucloxacillin on an empty stomach, at least 1 hour before or 2 hours after meals.
What Should I Avoid While Taking?
Avoid alcohol in excess, as it can increase side effects. Also, consult your doctor before taking other medications.
What Happens if I Miss a Dose?
Take the missed dose as soon as you remember unless it is almost time for the next dose. Do not double up to make up for a missed dose.
