[Pharmacogenetics and its importance in the clinical].

Therapeutic inefficacy and pharmacologic toxicity has frequently been seen in the clinical use of drugs or medicines in individuals under pharmacological treatment. Due to the presence of drug metabolizing enzymes, medicines may participate as substrate inhibitors or enzyme inductors. Their activity may vary among individuals. This enzymatic variability may be assessed through the analysis of recombinant DNA, using restriction analysis of the genomic DNA (fragment restriction of polymorphic length) and the enzymatic amplification of DNA through PCR (polymerase chain reaction). This technology has been used in clinical studies which allow us to know the mechanisms of inherited variations in response to drugs regulated by each individual's genes dependent on different races. These enzymatic differences may also be influenced by nutritional habits or environmental factors. This study deals with the importance of understanding the metabolism of drugs applied to the therapeutic management of individuals with therapeutic inefficacy or pharmacologic toxicity.