[Pharmacogenetics. Tailored therapy in medicine -- opportunities and challenges]

This article provides a general introduction into the field of pharmacogenetics and discusses its opportunities and limits. Pharmacogenetic research explores genetic variability between patients to explain observed differences in effectiveness of a drug therapy or adverse event profiles. Sometimes drug therapy is unfavourable: Patients may respond only partially to a drug therapy, do not respond at all, or suffer from serious adverse events. The reasons for the varying effectiveness of a drug therapy are due to factors like absorption; metabolism, elimination and target interaction. Recent research has led to a better understanding of the molecular genetic mechanisms behind those factors. Numerous new polymorphisms have been described, for example for the beta 2-adrenergic receptor or the cytochrome which can either improve or reduce the response to drug therapy. Two polymorphisms for the tumour necrosis factor alpha have shown to be associated with an increased risk of serious adverse events (hypersensibility: fever, rash, gastrointestinal symptoms) if treated with abacavir (HIV-treatment). Pharmacogenetic tests provide information about certain polymorphisms and raise the hope for an individualized pharmacotherapy. Yet, not only genetic but also environmental factors influence the effectiveness of a therapy. Even though results from research implies that pharmacogenetics has a great potential to maximize the effectiveness of pharmacotherapy and to reduce the incidence of drug-related adverse events, extensive clinical research both on effectiveness and costs is required to assess the true benefits of these exciting new technologies.