In October 2011 the Task Force Therapeutic Drug Monitoring of the Association for Neuropsychopharmacology and Pharmacopsychiatry (AGNP) published an update (Pharmacopsychiatry 2011, 44: 195-235) of the first version of the consensus paper on therapeutic drug monitoring (TDM) published in 2004. This article summarizes the essential statements to make them accessible to a wider readership in German speaking countries.