What is the dose of Vancomycin for severe infections?

Vancomycin Dosing for Severe Infections

For severe infections, vancomycin should be dosed at 15-20 mg/kg (actual body weight) every 8-12 hours, not to exceed 2 g per dose, in patients with normal renal function. 1, 2

Initial Dosing Recommendations

• For adults with severe infections (bacteremia, endocarditis, osteomyelitis, meningitis, pneumonia, necrotizing fasciitis), use 15-20 mg/kg (actual body weight) every 8-12 hours 1, 2
• In seriously ill patients (sepsis, meningitis, pneumonia, endocarditis), consider a loading dose of 25-30 mg/kg (actual body weight) 1
• When administering loading doses, consider prolonging infusion time to 2 hours and using an antihistamine to prevent red man syndrome 1
• Infusion rates should not exceed 10 mg/min to minimize infusion-related reactions 3

Therapeutic Monitoring

• Trough concentrations are the most accurate and practical method to guide vancomycin dosing 1, 2
• For severe infections, target trough concentrations of 15-20 μg/mL 1, 2
• Obtain serum trough concentrations at steady state, prior to the fourth or fifth dose 1, 2
• Monitoring of peak vancomycin concentrations is not recommended 1
• Trough monitoring is essential for serious infections and patients who are morbidly obese, have renal dysfunction, or have fluctuating volumes of distribution 1, 2

Special Considerations

Renal Function

• For patients with impaired renal function, dosage adjustment is necessary 3
• The daily vancomycin dose in mg is approximately 15 times the glomerular filtration rate in mL/min 3
• In patients with marked renal impairment, consider maintenance doses of 250-1,000 mg once every several days 3

Specific Infection Types

• For CNS infections (brain abscess, subdural empyema, spinal epidural abscess):

  • IV vancomycin for 4-6 weeks is recommended 1
  • Some experts recommend adding rifampin 600 mg daily or 300-450 mg twice daily 1

• For septic thrombosis of cavernous or dural venous sinus:

  • IV vancomycin for 4-6 weeks is recommended 1
  • Surgical evaluation for drainage of contiguous infection sites is recommended 1

Vancomycin MIC Considerations

• For isolates with vancomycin MIC <2 μg/mL, continue vancomycin if clinical response is adequate 1
• For isolates with vancomycin MIC >2 μg/mL (VISA or VRSA), use an alternative agent 1, 2
• The pharmacodynamic parameter that best predicts efficacy is AUC/MIC ratio >400 2, 4

Common Pitfalls and Caveats

• Underdosing vancomycin (1g every 12 hours) in critically ill patients often fails to achieve target trough concentrations of 15-20 μg/mL 5
• Traditional dosing of 1g every 12 hours is only adequate for non-severe infections in patients with normal renal function who are not obese 2
• Higher trough levels (15-20 μg/mL) are associated with increased nephrotoxicity risk but also with improved clinical outcomes in severe MRSA infections 4
• Weight-based dosing is particularly important in obese patients to prevent underdosing 2
• For persistent MRSA bacteremia or vancomycin treatment failures, search for and remove other foci of infection, and consider alternative agents 1

Pediatric Considerations

• For children with serious or invasive disease, IV vancomycin 15 mg/kg/dose every 6 hours is recommended 1
• Target trough concentrations of 15-20 μg/mL should be considered for serious pediatric infections 1