[Theoretical and practical problems concerning therapeutic drug monitoring from the viewpoint of the pharmacologist].

Drug treatment is aimed at achieving a maximum therapeutic benefit while minimizing unwanted side-effects. The recognition that drug doses administered to patients were often inadequate or excessive has highlighted the importance of measuring serum levels of drugs - by the methods of Therapeutic Drug Monitoring, - for effective patient care. The clinical usefulness of TDM has been undoubtedly demonstrated for a number of drugs. During 1990-1995 four commonly used anticonvulsive drugs, - carbamazepine, phenytoin, primidone and valproic acid - were monitored by an Abbott TDx machine, and the usefulness of TDM was further strengthened. In spite of some difficulties the number of samples located in the therapeutic range gradually elevated, assuring a better individual therapy and cost-benefit ratio. During the last 18 months similar results were obtained with theophylline and digoxin as well.