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Unit Code 81592:
Vancomycin, Trough

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Useful For

Monitoring adequate clearance of vancomycin near the end of a dosing

cycle  

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, eg, 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-resistant Staphylococcus 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 (eg, 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

PLASMA OR SERUM

      Therapeutic range: 7.0-20.0 ug/mL

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

(eg, central nervous system [CNS] infection) and when performing a

pharmacokinetic analyses in complex patients to more precisely adjust

doses. Typically 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

(eg, aminoglycosides, amphotericin, loop diuretics, etc.)

Cautions

No significant cautionary statements

Special Instructions and Forms

• Infectious Material 

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