Vancomycin

What is Vancomycin?

Vancomycin is a glycopeptide antibiotic used to treat serious bacterial infections caused by gram-positive bacteria, particularly those resistant to other antibiotics. It is considered a “last resort” antibiotic for severe infections, including those caused by methicillin-resistant Staphylococcus aureus (MRSA). Vancomycin is typically administered intravenously in hospital settings, though oral formulations exist for specific intestinal infections.

Uses

• MRSA infections: Treatment of serious infections caused by methicillin-resistant Staphylococcus aureus, including bloodstream infections, pneumonia, and skin infections
• Clostridioides difficile colitis: Oral vancomycin is used to treat severe C. diff infections of the colon when other treatments have failed
• Endocarditis: Treatment of heart valve infections, particularly those caused by enterococci or staphylococci
• Meningitis: Used for central nervous system infections when caused by resistant gram-positive bacteria
• Surgical prophylaxis: Prevention of infection in patients allergic to penicillin or when MRSA colonization is suspected

How it works

Vancomycin works by interfering with bacterial cell wall synthesis, specifically by binding to the building blocks of peptidoglycan, a crucial component of bacterial cell walls. This prevents bacteria from forming properly structured cell walls, leading to cell death. The antibiotic is particularly effective against gram-positive bacteria because their cell walls contain thick peptidoglycan layers that vancomycin can easily target.

Side effects

Common side effects:

• Nausea and vomiting
• Diarrhea
• Abdominal pain
• Headache
• Injection site reactions (pain, redness, swelling)
• Dizziness
• Fatigue
• Metallic taste in mouth

Serious side effects requiring immediate medical attention:

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• Hearing loss or ringing in ears (ototoxicity)
• Kidney problems (decreased urination, swelling, blood in urine)
• Red man syndrome (flushing, rash on face, neck, and upper body)
• Severe allergic reactions (difficulty breathing, swelling of face or throat)
• Severe diarrhea with blood or mucus

Warnings and precautions

• Kidney function monitoring: Regular blood tests are required to monitor kidney function, as vancomycin can cause nephrotoxicity, especially in patients with existing kidney disease or those taking other nephrotoxic drugs
• Hearing assessment: Periodic hearing tests may be necessary during prolonged treatment, as vancomycin can cause permanent hearing loss, particularly at high doses or with extended use
• Pregnancy considerations: Vancomycin crosses the placenta and should only be used during pregnancy when benefits clearly outweigh risks; it is generally considered compatible with breastfeeding
• Elderly patients: Older adults require careful dose adjustments due to age-related decline in kidney function and increased risk of adverse effects
• Infusion rate: Must be administered slowly (over at least 60 minutes) to prevent red man syndrome, a potentially dangerous reaction involving flushing and cardiovascular effects

Interactions

• Aminoglycosides (gentamicin, tobramycin): Increased risk of kidney and ear toxicity when used together
• Loop diuretics (furosemide): May enhance hearing loss and kidney damage
• Amphotericin B: Additive nephrotoxic effects that can severely damage kidneys
• Cisplatin: Increased risk of kidney toxicity and hearing loss
• Nonsteroidal anti-inflammatory drugs (NSAIDs): May increase risk of kidney problems
• Warfarin: Vancomycin may enhance anticoagulant effects, requiring more frequent blood clotting monitoring
• Cholestyramine: May reduce oral vancomycin absorption when taken for C. diff infections
• ACE inhibitors: Potential for increased kidney toxicity in susceptible patients

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Dosage

Vancomycin dosing is highly individualized and based on the patient’s weight, kidney function, and severity of infection. For adults with normal kidney function, typical intravenous doses range from 15-20 mg per kilogram of body weight every 8-12 hours, with a maximum single dose usually not exceeding 2 grams. For oral vancomycin used in C. difficile infections, the typical adult dose is 125-500 mg every 6 hours for 10-14 days. Blood levels are frequently monitored to ensure therapeutic effectiveness while minimizing toxicity. All dosing must be determined and adjusted by a qualified healthcare provider based on individual patient factors and response to treatment.

Sources: FDA DailyMed drug labels (public domain), BNF, WHO Essential Medicines List. This article is for informational purposes only and does not constitute medical advice. Always consult your healthcare provider before starting or stopping any medication.

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