What two pharmacokinetic parameters alter the half-life of medications?A. Loading dose and clearance
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.