[Customizing dosage drugs what contribution in therapeutic drug monitoring?].

Drug response is often variable from an individual to another: the same dose of drug administered to different patients could cause variable pharmacological effects in nature and intensity. Those effects are often the result of variability in drugs pharmacokinetics (absorption, distribution, metabolism and elimination) which alter their bioavailability. In fact, two factors should be taken into account: the disease(s) from which the patient suffers, and the associated drugs, because many drug interactions may alter their pharmacokinetics causing consequently quite enough of different therapeutic effects. The choice of the assay of the drug subject in monitoring is crucial, it allows quantifying the in vivo dose of the drug and the quality of compliance thereof, the pharmacokinetic characteristics allows the clinician to adjust the dosage by different approaches so that plasma concentrations are included in the therapeutic range. Therapeutic monitoring aims to increase clinical efficacy and to minimize toxicity.