Search our Test Catalog. Specify what to search (name, test code, titles, everywhere) and how to search (begins with, contains)

Unit Code 500127:
Vancomycin, Random, Serum

Print Friendly View
Print Page Email Page

Useful For

Monitoring adequacy of blood concentration during vancomycin therapy

Clinical Information

Vancomycin is an antibiotic used to treat infections caused by gram-

positive organisms that are resistant to beta-lactam antibiotics, such

as methicillin-resistant staphylococci (MRSA), Staphylococcus viridans

group, penicillin/cephalosporin-resistant Streptococcus pneumoniae,

and penicillin/ampicillin-resistant Enterococcus species (in combination

with an aminoglycoside if cidal therapy is needed, e.g., endocarditis).

The oral formulation, which is not absorbed, is used in the treatment of

pseudomembranous colitis caused by Clostridium difficile. Vancomycin

is also used for treatment of gram-positive organisms that are susceptible

to beta-lactams when patients are intolerant or have allergies to these

agents. It is an alternative to cefazolin for surgical prophylaxis.

 

Staphylococcal organisms are considered to have intermediate

resistance (vancomycin-intermediate Staphylococcus aureus [VISA])

with a minimal inhibitory concentration (MIC) of > or =4 ug/mL and are

resistant (vancomycin-resistantStaphylococcus aureus [VRSA]) with

a MIC of > or =16 ug/mL. Enterococcus organisms are considered

resistant to vancomycin (VRE) with a MIC of > or =16 ug/mL.

Vancomycin therapy is not effective for these resistant organisms.

 

Vancomycin is usually dosed based on the patient's weight (e.g., 15-20

mg/kg) and is usually administered twice per day by intravenous infusion.

Dosing amount or interval must be decreased to accommodate for

reduced renal function.

Reference Values

Therapeutic range:

25.0-50.0 ug/mL (Peak);

7.0-20.0 ug/mL (Trough)

Interpretation

Trough levels correlate better with efficacy than peak levels, with target

trough levels of 7 ug/mL to 20 ug/mL, depending on the type of infection.

Goal trough level:

         - 7 ug/mL to 15 ug/mL for most patients.

         - 10 ug/mL to 15 ug/mL for more serious infections such as

            bacteremia, endocarditis, and osteomyelitis.

         - 15 ug/mL to 20 ug/mL may be appropriate for nosocomial

            pneumonia or meningitis.

 

Peak levels are typically obtained when there are penetration limitations

(e.g., central nervous system [CNS] infection) and when performing a

pharmacokinetic analyses in complex patients to more precisely adjust

doses. Typical peak levels are in the 25 ug/mL to 50 ug/mL range. The

higher end of this range is used when targeting higher trough levels.

 

Random levels may be ordered when attempting to determine when to

redose vancomycin in patients with renal impairment/dialysis.

 

Ototoxicity can be seen with high vancomycin peak levels (>80 ug/mL).

Vancomycin alone is not commonly associated with nephrotoxicity, but

nephrotoxicity is relatively common when given with other nephrotoxins

(e.g., aminoglycosides, amphotericin, loop diuretics, etc.)

Cautions

No significant cautionary statements.

Clinical Reference

1.  Mandell GL: Principles and Practice of Infectious Diseases. London,

     Churchill Livingston Press, 1995

 

2.   Estes L, Wilson J:  Mayo Guide to Antimicrobial Therapy. Mayo Clinic,

      2005-2007

Key