MedCalc: Vancomycin Pharmacokinetics
* = minimum information needed for Revision calculations

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Step 1 : Patient Information :  
Gender : Age : years
Weight : Serum Creatinine :
Height :
Ideal Body Weight : kg
CrCl : ml/min CrCl : L/hr
* Vd : L * Kel : hr-1
t½ : hr
 
Step 2 : Based on displayed / current dose :  
Dose : mg * t :
hr   ( usu. 1-2 x t ½ )
( i.e. q12º, q24º, q48º )
* Target Cpss trough : mg/L * Time 'peak' obtained : hr   (usu. 1 hr + infusion time)
or
Cpss max : mg/L Cpss min : mg/L
 
Step 3 : Revisions :  
Actual 'trough' level : mg/L Time 'trough' obtained : hrs before (+) / after (-) t

If 'trough' were drawn on-time :  
kel = 
ln( 
dose / Vd + C (trough)
C (trough)
 )
t
Revised k : hr-1
Revised t½ : hr
(from Step 2)   Dose : mg
 Step 4 : Calculate revisions using this k & t½ 
'Trough' not drawn on-time :  
Cp (estim trough) = Cp0 ( e - kt )

Revised k = 
ln( 
Cpss max
Cp (estim trough)
 )
t - 2

Estimated trough (Cp) : mg/L
Revised k : hr-1
Revised t½ : hr
(from Step 2)   Dose : mg
 Step 4 : Calculate revisions using this k & t½ 
Cpss-anytime (mg/L) = 
Dose  ( e - kt )
Vd
( 1 - e - kt )
Revised k : hr-1
Revised t½ : hr
(from Step 2)   Dose : mg
 Step 4 : Calculate revisions using this k & t½ 
Cockcroft-Gault : GFR =  
(140 - age) x weight (kg)
PCr x 72
  x 0.85 (for women)
Vd (L) =  0.7 (L/kg) x (actual body weight)
kel (hr-1) = 
CrCl (L/hr)
Vd (L)
t½ (hr) = 
0.693
kel (hr-1)
  Dose (mg) = 
Cpss x Vd x ( 1 - e - kt )
e - kt
  Cpss max (mg/L) = 
Dose  ( e - kt )
Vd
( 1 - e - kt )
  Cpss min (mg/L) = 
Dose  ( e - kt )
Vd
( 1 - e - kt )
kel = 
ln( 
dose / Vd + C (trough)
C (trough)
 )
t

Created: Tuesday, January 9, 2001
Last Modified: