India · MRSA · Serious Gram-positive infections · Weight-based IV dosing · TDM · Renal Adjustment · Vancomax · Vancocin
CrCl >90: 15–20 mg/kg q8h
CrCl 50–90: 15–20 mg/kg q12h
CrCl 20–50: 15–20 mg/kg q24h
CrCl <20: 15–20 mg/kg then TDM-guided
⚠️ Haemodialysis: give after each dialysis session. TDM-guided redosing.
Flushing, erythema, pruritus on neck/face/upper body during infusion — not a true allergy
Prevention: infuse ≥60 min per gram. Never bolus.
Treatment: slow or stop infusion temporarily. Antihistamine (promethazine 25mg IV). Resume at slower rate.
Vancomycin is a glycopeptide antibiotic and the drug of choice for serious infections caused by methicillin-resistant Staphylococcus aureus (MRSA) and other resistant Gram-positive organisms including vancomycin-sensitive Enterococcus, penicillin-resistant Streptococcus pneumoniae (meningitis), and Clostridioides difficile (oral route only). India has extremely high rates of MRSA in hospital settings (40–70% of S. aureus isolates are MRSA in many Indian ICUs), making vancomycin one of the most important hospital antibiotics in the country. Its use requires TDM monitoring, precise renal dosing, and careful infusion technique to avoid toxicity.
Vancomycin distributes into total body water but not proportionally into adipose tissue. In obese patients, the loading dose may use actual body weight (to achieve rapid therapeutic levels) but maintenance dosing is typically based on Ideal Body Weight (IBW) or adjusted body weight. For patients with BMI >40, use AdjBW = IBW + 0.4 × (actual weight − IBW). This calculator uses the most appropriate weight automatically based on height and weight inputs.
Vancomycin must never be given as an IV bolus. Rapid infusion causes "Red Man Syndrome" — a histamine-mediated (non-IgE) reaction causing flushing, erythema, and pruritus on the face, neck, and upper torso, sometimes with hypotension. It is not a true allergy. Prevention: infuse each gram over at least 60 minutes (1000 mg = minimum 60 minutes; 1500 mg = 90 minutes; 2000 mg = 2 hours). For CNS infections requiring higher doses, infuse over 2–3 hours. If Red Man Syndrome occurs: slow or stop the infusion, give antihistamine, restart at a slower rate.
Traditional vancomycin TDM used trough levels (drawn 30 minutes before the next dose): target 10–15 mg/L for most infections, 15–20 mg/L for severe infections. Current ASHP/IDSA/SIDP guidelines (2020) now recommend AUC/MIC monitoring as the preferred approach for serious infections — targeting AUC24 400–600 mg·h/L — because trough monitoring alone may overestimate nephrotoxicity risk at high trough targets. In most Indian centres, AUC monitoring is not yet routinely available; trough monitoring remains the practical standard. Trough target: 10–15 mg/L (moderate infections), 15–20 mg/L (bacteraemia, endocarditis, meningitis). Draw trough 30 minutes before the 4th or 5th dose (steady state).
Oral vancomycin 125 mg four times daily for 10 days is first-line treatment for Clostridioides difficile infection (CDI) in India, where metronidazole is now considered second-line (per IDSA 2017 guidelines). Oral vancomycin is NOT absorbed systemically — it acts locally in the colon. It cannot be used as oral vancomycin for MRSA or other systemic infections. IV vancomycin does NOT work for CDI (insufficient colonic concentration after IV administration).