Psychopharmaka: Pharmakogenetik und therapeutisches drug-monitoring

Pharmacogenetics studies the genetic basis of an individual's ability to respond to pharmacotherapy. The variability of this response is a major problem in psychiatry. In depression and schizophrenia, 30 to 50 % of all patients do not respond sufficiently to the initial treatment and it can take up to 6 weeks for these therapy-resistant patients to be identified. On the other hand, fatal adverse drug reactions have been reported to be the fourth leading cause of death in the USA. Much knowledge has been gathered throughout the last 3 decades about the genetic basis of pharmacokinetic and pharmacodynamic variability. Genetic tests suitable for the routine laboratory are now available. The possible use of these tests in the clinical practice of monitoring antidepressive and antipsychotic drug therapy is discussed. Genotyping tests for drug metabolising enzymes are compared to older phenotyping methods and therapeutic drug monitoring. Less well studied than the genetics of pharmacokinetics is the genetic basis of pharmacodynamic variability. Current knowledge in this young field of research is summarized.