Interindividual differences in drugs with regard to efficacy and safety are a significant health care problem and genetic variation contributes to this. The aims of this study were to give an overview of the current knowledge on pharmacogenetics and regulatory aspects, and to discuss questions on the problems of implementation in the clinic by reviewing the recent literature. The guidelines of the Clinical Pharmacogenetics Implementation Consortium (CPIC) are currently the scientifically most advanced starting point for pharmacogenetics-based selection and dosing of selected drugs. On a national level, the guidelines of the gene diagnostics commission provide a framework of which classes should be considered in the classification of the significance of hereditary variants in relation to their efficacy and tolerability. Although there is already evidence for certain gene–drug pairs with regard to their clinical and economic utility, there is a need to prove the success of the clinical application of a large number of gene–drug pairs through prospective or preemptive genotyping-based studies. Such studies are currently ongoing in large research consortia, in Europe and especially in North America.