Pharmacology

Question 1

Drug clearance

Answer 1

=Elimination rate constant (Kel) x volume of distribution (Vd)

= (Dose/interval)/average steady state concentration

Question 2

Elimination half life (t1/2)

Answer 2

= 0.693/Kel
= 0.693xVd/drug clearance

Kel = drug clearance/Vd

Question 3

Loading dose (mg/kg)

Answer 3

(Volume of distribution x Cp)/(SxF)

Volume of distribution L/kg
Cp = [plasma] mg/dl (can be desired - current)
S = fraction of drug which is active
F= fraction of drug which is bioavailable

Assumes values of 1 if not given
Multiply by weight for total dose in mg only

Question 4

Steady state concentration

Answer 4

= Infusion rate /drug clearance
= Infusion rate / (Vs x elimination rate constant)

Question 5

TPN Osm

Answer 5

(a.ax8) + (glucosex7) + (Nax2) + (Px0.2) - 50