TDM is defined as “individualization of dosage by maintaining plasma or blood concentrations within a target range (therapeutic range/therapeutic window). It is pragmatic manipulation of the dose of a drug using plasma concentration as a guide to optimize its efficacy, to avoid or identify toxicity and to detect or confirm poor compliance”. Students will learn about timing of samples, drug estimation methods, and interpretation of data and then how to modify dosage. An example of antiepileptic drug monitoring will be explained.