Question 3#

What two pharmacokinetic parameters alter the half-life of medications?

A. Loading dose and clearance
B. Absorption and clearance
C. Vd and clearance
D. Absorption and Vd

Correct Answer is C


c. Vd and clearance. Half-life is a function of both clearance (Cl) and Vd . The elimination-rate constant (kel ) is determined by two independent factors: Cl and Vd . kel = Cl/Vd . Half-life is determined by the equation 0.693/kel . Therefore, as the apparent Vd and Cl change, the half-life of a drug may change.