[Pediatric pharmacology. Practical ideas of kinetics and metabolism of drugs].

After administration, a drug does not exert immediately all its actions. Rates of diffusion, fixation and excretion of drugs are depending from their nature as well as from the condition of the body to which they are given. The resultant of these mechanisms control the blood level of a drug, level which varies in function of time. The blood level reflects the pharmacodynamic activity of a drug. Information on kinetics and significance of the status of drug equilibrium are of major importance for rational drug administration.