Vancomicin

# Vancomicin ## Overview - **Classification**: Glycopeptide antibiotic - **Mechanism**: Inhibits bacterial cell wall synthesis by binding to D-Ala-D-Ala terminus of peptidoglycan precursors, blocking cross-linking. ## Primary Indications 1. **Serious Gram-Positive Infections**: Treatment of multi-drug resistant Gram-positive infections, especially Methicillin-resistant *Staphylococcus aureus* (MRSA). 2. ***Clostridioides difficile* Infection (CDI)**: Oral formulation used for treatment of CDI, particularly severe or recurrent cases. 3. **Prophylaxis**: Surgical prophylaxis in patients with MRSA colonization or beta-lactam allergy. ## Adult Dosing ### Standard Dosing **Serious Gram-Positive Infections (IV)** - **Dose**: **15-20 mg/kg** (based on actual body weight) - **Frequency**: Every **8-12 hours** - **Route**: Intravenous (IV) infusion over at least 60 minutes - **Maximum Dose**: Typically **2000 mg** per dose (or **60 mg/kg/day**) - **Target Trough**: **10-15 mcg/mL** for less severe infections; **15-20 mcg/mL** for severe infections (e.g., endocarditis, osteomyelitis, pneumonia, sepsis). ***Clostridioides difficile* Infection (Oral)** - **Dose (Non-severe)**: **125 mg** - **Frequency**: Four times daily (QID) - **Route**: Oral (PO) - **Duration**: 10 days - **Dose (Severe/Recurrent)**: **250-500 mg** - **Frequency**: Four times daily (QID) - **Route**: Oral (PO) - **Duration**: 10-14 days ### Dose Adjustments - **Renal Impairment**: Requires significant dose adjustment based on creatinine clearance (CrCl). - **CrCl >50 mL/min**: Standard dosing (q8-12h). - **CrCl 20-49 mL/min**: Consider **15 mg/kg** every 24-48 hours. - **CrCl <20 mL/min or Hemodialysis (HD)**: Initial dose **15 mg/kg**; subsequent doses guided by levels, often **1000 mg** q7 days or **500 mg** post-dialysis. - **Note**: Monitoring vancomycin troughs and renal function is essential. - **Hepatic Impairment**: No specific dose adjustment needed; vancomycin is primarily renally eliminated. - **Elderly Patients**: Often have reduced renal function; dose adjust based on CrCl, not age alone. Start with lower doses and monitor closely. ## Pediatric Dosing ### Neonates (0-28 days) - **Dose**: - **PNA <7 days**: **15 mg/kg** initial dose, then **10 mg/kg** every 12-24 hours (interval varies by gestational age and postnatal age). - **PNA >7 days**: **15 mg/kg** initial dose, then **10-15 mg/kg** every 8-12 hours. - **Frequency**: As above, highly individualized. - **Maximum**: Typically **60 mg/kg/day**. - **Special Notes**: Requires careful therapeutic drug monitoring (TDM) due to variable renal clearance in neonates. Infuse over at least 60 minutes. ### Infants (1-12 months) - **Dose**: **15 mg/kg** - **Frequency**: Every **6 hours** (total **60 mg/kg/day**) - **Maximum**: **2000 mg** per dose. ### Children (1-12 years) - **Dose**: **15 mg/kg** - **Frequency**: Every **6 hours** (total **60 mg/kg/day**) - **Maximum**: **2000 mg** per dose. Target troughs **10-20 mcg/mL**. ### Adolescents (13-18 years) - **Dose**: Approach as adult dosing, **15-20 mg/kg** - **Frequency**: Every **8-12 hours** - **Maximum**: **2000 mg** per dose or **60 mg/kg/day**. ## Safety Information ### Contraindications - **Absolute**: Hypersensitivity to vancomycin. ### Common Adverse Effects - **Very Common (>10%)**: - **Infusion-related reactions (Red Man Syndrome)**: Flushing, rash, pruritus, hypotension (due to rapid infusion). - Phlebitis/injection site pain. - **Common (1-10%)**: - **Nephrotoxicity**: Dose-related, increased risk with high troughs, prolonged therapy, or concomitant nephrotoxins. - Ototoxicity (hearing loss, tinnitus): Rare, typically with very high doses/troughs and pre-existing renal impairment. - Rash, fever. - **Serious but Rare**: - Agranulocytosis, neutropenia, thrombocytopenia (reversible). - Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS). ### Key Drug Interactions - **Nephrotoxic Agents (e.g., aminoglycosides, NSAIDs, loop diuretics, amphotericin B, cyclosporine)**: Increased risk of nephrotoxicity. - **Ototoxic Agents (e.g., aminoglycosides, loop diuretics)**: Potentiated risk of ototoxicity. - **Neuromuscular Blockers**: May enhance neuromuscular blockade. ## Monitoring & Follow-up - **Before Treatment**: - Baseline renal function (SCr, BUN). - Baseline audiogram if pre-existing hearing impairment. - **During Treatment**: - **Vancomycin Trough Levels**: - Measure before 4th or 5th dose (at steady state). - Monitor at least weekly or more frequently in unstable renal function. - **Renal Function**: Monitor SCr and BUN at least 2-3 times per week. - **Clinical Signs**: Watch for signs of nephrotoxicity (decreasing urine output, rising SCr), ototoxicity (hearing changes, tinnitus), or Red Man Syndrome. ## Clinical Pearls - 💡 **Infusion Rate**: Always infuse vancomycin slowly, over at least **60 minutes** (or 10 mg/min), to prevent Red Man Syndrome. - 💡 **Oral vs. IV**: Oral vancomycin is NOT absorbed systemically and is only used for *C. difficile* infections. IV vancomycin is ineffective for CDI. - 💡 **Trough Monitoring**: Target troughs are essential for efficacy and minimizing toxicity; interpret in context of clinical response and renal function. - 💡 **Therapeutic Drug Monitoring (TDM)**: **Area Under the Curve (AUC)** monitoring is gaining favor over troughs, aiming for an AUC24/MIC ratio of **400-600** for MRSA. > **⚠️ Important**: This information is for educational purposes only. Always consult current prescribing information, local guidelines, and clinical judgment before prescribing.