Example: Amrinone is a drug used to improve the cardiac output through its vasodilatation and positive inotropic actions. Its Vd is 2 L/kg and elimination rate constant is 0.16 hr-1. Recommend an iv loading dose and an infusion rate to maintain amrinone plasma conc at 1.5mg/L.

Loading dose

Dose = Cp0 .Vd
Cp0 =

Dose

Vd
Cps.s. =

K0

CLT

Answer:

Loading dose:

= 1.5mg/L X 2 L/kg = 3 mg/kg

Infusion rate:

= 1.5mg/L X 2 L/kg X 0.16 hr-1

=0.48 mg/kg/hr

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