Fluclox

# Fluclox ## Overview - **Classification**: Penicillin antibiotic, Beta-lactam, Anti-staphylococcal penicillin. - **Mechanism**: Inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), leading to bacterial cell lysis. Bactericidal. ## Primary Indications 1. **Staphylococcal Infections** - Skin and soft tissue, bone and joint, respiratory tract, endocarditis. 2. **Streptococcal Infections** - When co-infection with Staph is suspected. 3. **Surgical Prophylaxis** - In procedures with high risk of staphylococcal infection. ## Adult Dosing ### Standard Dosing **Mild-Moderate Infections (e.g., Cellulitis, Folliculitis)** - **Dose**: **250-500 mg** - **Frequency**: Four times daily (QID) - **Route**: Oral (PO) - **Duration**: Typically 5-14 days **Severe Infections (e.g., Osteomyelitis, Endocarditis, Septicaemia)** - **Dose**: **1-2 g** - **Frequency**: Four times daily (QID) - **Route**: Intravenous (IV) - **Maximum Dose**: Up to **12 g/day** IV - **Duration**: Varies, e.g., 4-6 weeks for osteomyelitis, 4-6 weeks for endocarditis **Surgical Prophylaxis** - **Dose**: **1-2 g** - **Frequency**: Single dose at induction of anaesthesia - **Route**: Intravenous (IV) - **Special Consideration**: May give further doses if surgery prolonged or high risk. ### Dose Adjustments - **Renal Impairment**: * CrCl > 10 mL/min: No adjustment needed. * CrCl < 10 mL/min (including hemodialysis): Reduce dose or extend interval (e.g., **1 g** Q8-12H). * Monitor for accumulation in severe impairment. - **Hepatic Impairment**: * Use with caution. Monitor liver function tests (LFTs) closely. * Avoid if history of flucloxacillin-associated jaundice/hepatitis. - **Elderly Patients**: * Adjust based on renal function. Monitor LFTs due to increased risk of hepatotoxicity. ## Pediatric Dosing ### Neonates (0-28 days) - **Dose**: **25 mg/kg/dose** (IV/PO) - **Frequency**: Q12H for 0-7 days old; Q8H for 7-28 days old. - **Maximum**: **100 mg/kg/day**. - **Special Notes**: IV preferred for serious infections. Oral suspension available. ### Infants (1-12 months) - **Dose**: **12.5-25 mg/kg/dose** (IV/PO) - **Frequency**: Q6H. - **Maximum**: **100 mg/kg/day**. ### Children (1-12 years) - **Dose**: **12.5-25 mg/kg/dose** (IV/PO) - **Frequency**: Q6H. - **Maximum**: **100 mg/kg/day** (or up to **4 g/day**). ### Adolescents (13-18 years) - **Dose**: Approach adult dosing, typically **250-500 mg** Q6H PO, or **0.5-1 g** Q6H IV. - **Maximum**: Up to **4 g/day** PO or **12 g/day** IV. ## Safety Information ### Contraindications - **Absolute**: Hypersensitivity to penicillins or any beta-lactam antibiotic. - **Absolute**: History of flucloxacillin-associated jaundice or hepatic dysfunction. ### Common Adverse Effects - **Common (1-10%)**: Nausea, vomiting, diarrhea, abdominal discomfort, rash, urticaria. - **Serious but Rare**: Anaphylaxis, cholestatic hepatitis/jaundice, pseudomembranous colitis, interstitial nephritis, neutropenia, agranulocytosis. ### Key Drug Interactions - **Warfarin**: Flucloxacillin can enhance anticoagulant effect. Monitor **INR** closely, adjust warfarin dose as needed. - **Methotrexate**: Decreased renal clearance of methotrexate. Monitor for methotrexate toxicity. - **Oral Contraceptives**: May reduce efficacy due to altered gut flora. Advise additional contraceptive methods. - **Probenecid**: Increases and prolongs flucloxacillin plasma levels. Used therapeutically to boost levels. ## Monitoring & Follow-up - **Before Treatment**: Assess allergy history, baseline renal and hepatic function (if prolonged therapy or pre-existing conditions). - **During Treatment**: Monitor for signs of hypersensitivity (rash), gastrointestinal upset. - **During Prolonged Treatment**: Monitor LFTs (especially beyond 2 weeks), renal function, full blood count. - **Clinical Signs**: Watch for persistent rash, jaundice (yellow skin/eyes), dark urine, severe diarrhea, fever. ## Clinical Pearls - 💡 **Tip 1**: Administer **1 hour before or 2 hours after meals** for optimal absorption (empty stomach). - 💡 **Tip 2**: Excellent first-line agent for suspected **Staphylococcus aureus** skin and soft tissue infections. - 💡 **Tip 3**: Counsel patients to **complete the full course** of antibiotics, even if symptoms improve. - 💡 **Tip 4**: Advise patients to seek medical attention if they develop yellowing of skin/eyes, persistent nausea, or dark urine. > **⚠️ Important**: This information is for educational purposes only. Always consult current prescribing information, local guidelines, and clinical judgment before prescribing.