What is the recommended dosage of intravenous (IV) vancomycin?

Intravenous Vancomycin Dosing

For adults with normal renal function, administer vancomycin at 15-20 mg/kg (actual body weight) every 8-12 hours, with each dose not exceeding 2 g and infused over at least 60 minutes at a rate not exceeding 10 mg/min. 1, 2

Standard Dosing Regimen

Adults with Normal Renal Function

• Administer 15-20 mg/kg (actual body weight) every 8-12 hours, not exceeding 2 g per dose 1, 3, 2
• Each dose must be infused over at least 60 minutes at a rate not exceeding 10 mg/min 2
• Use concentrations no greater than 5 mg/mL to minimize infusion-related reactions 2
• Traditional fixed dosing of 1 g every 12 hours is inadequate for most patients and leads to underdosing, particularly in those weighing >70 kg or with obesity 1, 3

Pediatric Patients

• Administer 10 mg/kg per dose every 6 hours 2
• Alternative dosing from specialized guidelines: 40-60 mg/kg/day divided every 6-8 hours depending on infection severity 4
• Each dose should be administered over at least 60 minutes 2

Neonates

• Initial dose: 15 mg/kg, followed by 10 mg/kg every 12 hours for the first week of life, then every 8 hours thereafter up to 1 month of age 2
• Premature infants require longer dosing intervals due to decreased vancomycin clearance as postconceptional age decreases 2

Loading Dose for Serious Infections

For seriously ill patients with suspected MRSA infection, sepsis, meningitis, pneumonia, endocarditis, or necrotizing fasciitis, administer a loading dose of 25-30 mg/kg (actual body weight) 1, 3, 5

• The loading dose rapidly achieves therapeutic concentrations and is critical in serious infections 1
• Prolong infusion time to 2 hours and consider premedication with an antihistamine to reduce red man syndrome risk 1, 3
• The loading dose is NOT affected by renal function—only maintenance doses require adjustment for renal impairment 1, 3
• Fixed 1 g loading doses fail to achieve therapeutic levels in most patients, especially those >70 kg 1

Therapeutic Monitoring

Target Trough Concentrations

• For serious infections (bacteremia, endocarditis, meningitis, pneumonia): target trough 15-20 μg/mL 1, 3, 5, 6
• For non-severe infections: target trough 10-15 μg/mL 1
• Trough concentrations are the most accurate and practical method to guide vancomycin dosing 1, 3, 6

Monitoring Protocol

• Obtain trough concentrations at steady state, prior to the fourth or fifth dose 1, 5
• Monitoring is mandatory in patients with renal dysfunction, obesity, or fluctuating volumes of distribution 1, 3
• For non-severe skin and soft tissue infections in patients with normal renal function who are not obese, trough monitoring is not required 1

Pharmacodynamic Target

• The AUC/MIC ratio >400 is the pharmacodynamic parameter that best predicts vancomycin efficacy 1, 3, 6
• Trough concentrations of 15-20 μg/mL generally correlate with achieving the target AUC/MIC ratio 1

Dosing Adjustments for Renal Impairment

Dosage adjustment is mandatory in patients with impaired renal function 2

• The vancomycin dose per day in mg is approximately 15 times the glomerular filtration rate in mL/min 2
• Initial dose should be no less than 15 mg/kg, even in patients with mild to moderate renal insufficiency 2
• In marked renal impairment, maintenance doses of 250-1,000 mg once every several days may be more convenient than daily dosing 2
• In anuria, a dose of 1,000 mg every 7-10 days has been recommended 2

Common Pitfalls and How to Avoid Them

Underdosing

• Never use fixed 1 g doses without considering patient weight—this results in underdosing in the majority of patients 1, 3
• Weight-based dosing is critical, particularly in obese patients who are likely to be underdosed with conventional 1 g every 12 hours strategies 1

Inappropriate Target Levels

• Do not target high trough levels (15-20 μg/mL) for non-severe infections, as this unnecessarily increases nephrotoxicity risk 1, 3
• Nephrotoxicity risk increases with trough levels >15 mg/L, especially when combined with other nephrotoxic agents 1
• Patients with class III obesity (BMI ≥40 kg/m²) are 3 times more likely to develop nephrotoxicity compared to non-obese patients 7

MIC Considerations

• If vancomycin MIC is ≥2 μg/mL, consider alternative therapies (daptomycin, linezolid, ceftaroline) as target AUC/MIC ratios may not be achievable 1, 3, 5, 6

Concomitant Nephrotoxins

• Concomitant administration of piperacillin-tazobactam, diuretics, and IV contrast increases nephrotoxicity risk 7
• Longer durations of therapy and higher initial maintenance doses are predictors of nephrotoxicity development 7