Vancomycin

Question 1

MOA

Answer 1

Inhibits stage two of cell wall synthesis by binding to D-ala-D-ala cell wall precursors

Slowly bactericidal in a time-dependent manner

Question 2

MOR

Answer 2

VRE and VRSA resistance to vancomycin is due to modification of D-ala-D-ala binding site

VISA resistance is due to thickening of the peptidoglycan layer of the cell wall

Question 3

Spectrum of activity

Answer 3

Gram (+) aerobes and Gram (+) anaerobes
- PRSP
- MSSA
- MRSA–> DOC
- C. diff

Question 4

Absorption

Answer 4

Absorption from the GI tract is negligible after oral administration but can be used for C. diff

For treatment of systemic infections, intermittent IV infusion is preferred route of administration (not IM)

Question 5

Distribution

Answer 5

Widely distributed into tissues and fluids

Vancomycin takes approximately ONE HOUR to distribute from plasma compartment into peripheral tissues

Vd adults= 0.6 to 0.7 L/kg

Displays variable penetrations into CSF even in presence of inflamed meninges

Question 5

Elimination

Answer 5

Primarily eliminated unchanged in the kidneys

In adults with normal renal function, the t1/2= 6-8 hours

The t1/2 progressively increases as renal function decreases

In patients with ESRD the t1/2 is 7-14 days

Question 6

Serum concentration monitoring

Answer 6

Peak concentrations should be obtained 60 minutes after infusion

Question 7

Dosing

Answer 7

TBW should be used for dosing in obese patients–> MAX initial doses should not exceed 2000 to 3000 mg

Question 8

Clinical uses

Answer 8

MRSA

Serious Gram (+) infections in patients allergic to B-lactam antibiotics

PRSP

ORAL vancomycin for C. diff

Question 9

Adverse Effects

Answer 9

Red mans syndrome–> related to the rate of infusion

Vancomycin doses of 1 gram should be infused over at least 1 hour and larger doses should be infused over 90 to 120 minutes

Nephrotoxicity and Ototoxicity
- Risk factors include–> renal dysfunction, high doses, loop diuretics

Thrombophlebitis

Interstitial nephritis