There is a growing body of evidence that the observed characteristics in pharmacokinetics and pharmacodynamics of drugs are genetically determined and that they primarily include drug metabolism and transport processes. Current acknowledge-ments, based on collected evidence, clearly show that an early adjustment of therapy regime to genetic characteristics of patients may help to avoid side effects. Such an approach stands for an individualized, optimal therapeutic use of drugs, based on the dose regime adjusted to an individual genotype. Gene therapy is the intentional transfer of genetic material into human somatic cells in prophylactic, therapeutic or diagnostic purposes. While the gene transfer technology is very advanced, ethical princ...