Therapeutic drug monitoring specializes in the measurement of drug concentrations in biological fluids and may serve as a practical aid to clarify various conditions of unexpect response to chronic drug treatment. Briefly, its main purpose is to optimize and/or individualize dosage regimens to maintain efficient and safe drug therapy. This is acieved by maintaining serum/plasma drug concentrations within a target range (therapeutic range, therapeutic window), which is defined as the range of plasma drug concentrations that produce therapeutic effects with minimal risk of adverse responses/side or toxic effects. In this review, indications, practical applications as well as the clinical value and cost-effectiveness of therapeutic drug monitoring is discussed.

Therapeutic drug monitoring specializes in the measurement of drug concentrations in biological fluids and may serve as a practical aid to clarify various conditions of unexpect response to chronic drug treatment. Briefly, its main purpose is to optimize and/or individualize dosage regimens to maintain efficient and safe drug therapy. This is acieved by maintaining serum/plasma drug concentrations within a target range (therapeutic range, therapeutic window), which is defined as the range of plasma drug concentrations that produce therapeutic effects with minimal risk of adverse responses/side or toxic effects. In this review, indications, practical applications as well as the clinical value and cost-effectiveness of therapeutic drug monitoring is discussed