ABSTRACT
The amount of the drug in the body decreases due to drug elimination leading to reduction in the plasma drug concentration. The rate of drug elimination affects the rate of decline in the plasma drug concentration, which has signicant clinical consequences after single-and multiple-drug administration. Assuming the existence of direct relationship between the plasma drug concentration and drug effect, the duration of drug effect depends on the rate of decline in the plasma drug concentration. For example, the duration of effect of a general anesthetic that is eliminated rapidly from the body is shorter than the duration of effect of general anesthetics that are eliminated from the body at slower rate. During multiple drug administrations, drugs that are eliminated rapidly from the body have to be administered more frequently compared to drugs that are eliminated at slower rate. For example, the antibiotics that are eliminated rapidly from the body are usually
administered every 4, 6, or 8 h, while those with slower rate of elimination are administered less frequently.
