What is the appropriate vancomycin loading dose for a patient weighing 62.7 kg?

Vancomycin Loading Dose for 62.7 kg Patient

For a patient weighing 62.7 kg, administer a vancomycin loading dose of 1,565-1,880 mg (25-30 mg/kg based on actual body weight), rounded to the nearest practical dose of either 1,500 mg or 2,000 mg, infused over at least 2 hours. 1, 2

Calculation and Rationale

• The recommended loading dose is 25-30 mg/kg based on actual body weight for seriously ill patients with suspected or documented MRSA infections 1, 2
• For a 62.7 kg patient:
  • Lower range: 25 mg/kg × 62.7 kg = 1,567.5 mg
  • Upper range: 30 mg/kg × 62.7 kg = 1,881 mg
• Round to practical doses: either 1,500 mg or 2,000 mg depending on infection severity 1

When Loading Doses Are Essential

• Loading doses are critical for serious infections including sepsis, meningitis, pneumonia, endocarditis, necrotizing fasciitis, and bacteremia to rapidly achieve therapeutic concentrations 1, 2
• Seriously ill patients have expanded extracellular volume from fluid resuscitation, which increases vancomycin's volume of distribution and delays achievement of therapeutic levels without a loading dose 1
• Fixed 1-gram doses fail to achieve early therapeutic levels in most patients, particularly those weighing >70 kg 1

Administration Guidelines

• Infuse the loading dose over at least 2 hours (not the standard 1 hour) to minimize risk of red man syndrome and infusion-related reactions 1, 2
• Consider antihistamine premedication before administering large loading doses to prevent hypersensitivity reactions 1, 2
• The loading dose is NOT affected by renal function—only maintenance doses require adjustment for renal impairment 1

Maintenance Dosing After Loading

• Following the loading dose, administer maintenance doses of 15-20 mg/kg every 8-12 hours (approximately 940-1,250 mg for this patient) 1, 3
• For serious infections, target trough concentrations of 15-20 μg/mL to achieve the therapeutic AUC/MIC ratio >400 1, 2, 4
• Obtain the first trough level before the fourth or fifth maintenance dose to guide further dosing adjustments 1, 2

Critical Pitfalls to Avoid

• Never use fixed 1-gram doses—this results in underdosing for most patients and delays therapeutic concentration achievement 1
• Do not reduce the loading dose in patients with renal dysfunction; only maintenance doses require adjustment based on kidney function 1
• Avoid rapid infusion rates faster than 10 mg/min or infusion times shorter than 2 hours for large doses, as this significantly increases risk of red man syndrome 1, 3
• Do not skip the loading dose in critically ill patients even if renal function is impaired—therapeutic concentrations must be achieved rapidly in serious infections 1