Is a loading dose of vancomycin (Vanco) necessary for patients already on vancomycin who are starting Sustained Low-Efficiency Dialysis (SLED)?

Vancomycin Loading Dose for Patients Already on Vancomycin Starting SLED

No, you do not give a loading dose of vancomycin to patients already on vancomycin when starting SLED; instead, give a supplemental post-SLED dose of at least 500-1000 mg after each dialysis session to replace drug removed during dialysis. 1, 2

Understanding Vancomycin Removal During SLED

The key issue is not whether the patient needs initial loading, but rather understanding that SLED significantly removes vancomycin from the bloodstream:

• SLED removes approximately 35-36% of vancomycin during a typical 7-8 hour treatment session 1, 2
• The majority of drug removal (approximately 30%) occurs during the first 4 hours of SLED, with only 9% removed during the last 4 hours 2
• Vancomycin rebound after SLED is minimal at only 9.8%, meaning what's removed stays removed 1
• The elimination half-life during SLED is approximately 13.6 hours 1

Clinical Decision Algorithm

For Patients Already on Vancomycin Starting SLED:

1. Check pre-SLED vancomycin level if available

   • If pre-SLED level is 20-30 mcg/mL, expect it to drop to 13-20 mcg/mL post-SLED 2
   • Nearly half of patients fall below therapeutic range (<15 mcg/mL) after an 8-hour SLED session 2

2. Administer supplemental dose post-SLED:

   • Give at least 500-1000 mg after each SLED session to maintain therapeutic concentrations 1, 2
   • Target a post-SLED peak of 20-30 mcg/mL 1

3. Do NOT give a loading dose (25-30 mg/kg) unless:

   • The patient has never received vancomycin before
   • Pre-SLED levels are subtherapeutic and the patient has severe sepsis/septic shock 3

Why Loading Doses Are for Treatment Initiation, Not SLED Initiation

Loading doses of 25-30 mg/kg are specifically indicated for:

• Seriously ill patients with suspected MRSA infection who have not yet received vancomycin 3, 4
• Achieving rapid therapeutic concentrations in critically ill patients with expanded extracellular volume from fluid resuscitation 3
• The loading dose is not affected by renal function and should be given regardless of kidney status 3

However, loading doses are NOT indicated when a patient is already on vancomycin therapy - the issue with SLED is replacement of removed drug, not initial loading.

Practical Dosing Strategy for SLED Patients

• Vancomycin clearance during SLED is highly variable (mean 5.97 L/h on SLED vs 2.40 L/h off SLED) 5
• For patients receiving daily SLED, consider a regimen of 1600 mg daily after an initial 2400 mg loading dose (if treatment-naive) 5
• Therapeutic drug monitoring is essential - check levels before and after SLED sessions 1, 2, 5

Common Pitfalls to Avoid

• Do not assume standard intermittent hemodialysis or CRRT dosing applies to SLED - SLED is a hybrid modality with unique pharmacokinetics 1, 5
• Do not skip post-SLED supplemental dosing - patients are at significant risk for undertreatment of infections without replacement dosing 2
• Do not give unnecessary loading doses to patients already on vancomycin - this increases nephrotoxicity risk without benefit 3
• Do not rely on fixed dosing - the narrow therapeutic window and high variability in critically ill patients receiving SLED mandates individualized therapeutic drug monitoring 5