Example:

After a single iv dose of 100 mg lidocaine the following concentrations wers obtained:

  • at time 0 hrconc 2 mg/L
  • at time 1.5 hrconc 0.9 mg/L
  • at time 3.0 hrconc 0.5 mg/L
  • at time 6.0 hrconc 0.1 mg/L

Calculate lidocaine AUC using the trapezoidal rule (lidocaine t1/2 is 1.5 hr)

0, 2
1
1.5, 0.9
2
3, 0.5
3
6, 0.1
tail

Area of the trapezoid

= (

Cpn+Cpn+1

2) .(tn+1 - tn)
(

2+0.9

2 ) .(1.5-0) = 2.175 mg-hr/L +
(

0.9+0.5

2 ) .(3-1.5) = 1.05 mg-hr/L +
(

0.5+0.1

2 ) .(6-3) = 0.9 mg-hr/L +
(

0.1

k ) = (

0.1

.693/1.5 hr ) = 0.216 mg-hr/L

AUC = 4.341 mg-hr/L

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