Optimizing treatment with psychotropic agents through precision drug therapy: It is not about the mean

In science significant differences between the averages of groups are considered important. However, in practice physicians have to treat individuals. Therefore there has been an increasing interest in the application of personalized medicine and consequently for personalized pharmacotherapy. In the dissertation of Ms. Berm, two aspects of personalized medicine are addressed. Firstly, increasing patients comfort in the determination of drug concentrations in blood with the help of dried blood spot sampling and analysis. Methods for dried blood spot analysis of common antidepressants were developed and validated. Secondly, analysis of genetic characteristics could be used to predict a patient’s drug concentration at a certain dose. For this purpose the relation between genetic characteristics and blood drug concentrations of nortriptyline and venlafaxine were studied in old aged patients. Next, a model was used to assess the costs and effects of routine application of this genetic testing among old aged nortriptyline users. In the model, care as usual including therapeutic drug monitoring was used as a reference treatment strategy. With this dissertation, an insight is given into the added value of genetic testing in a specific population. In addition, analytical methods using dried blood spot sampling were developed and implemented in a research setting. In the future, such analytical methods could be used to facilitate more research in the field of personalized medicine.