After iv bolus administration, the drug is distributed into all parts of the body via the systemic circulation. Then the amount of drug in the body declines at a rate that determines the .
The elimination rate constant is different for different drugs and is dependent on the apparent body volume in which the drug is distributed (volume of distribution) and the efficiency of the eliminating organs of the drug (total body clearance).
The elimination rate constant of a drug may change due to changes in the function of the organ responsible for drug elimination (e.g. kidney or liver).
The elimination rate constant (k) hr -1
Larger k means faster
rate of drug elimination
