The role of therapeutic drug monitoring in children.

Routine use of therapeutic drug monitoring in children is helpful in individualizing the dosage during long term treatment (e.g. theophylline and antiepileptic drugs) and in checking against toxic accumulation of drug in neonates (e.g. digoxin, theophylline/caffeine and aminoglycoside antibiotics). In individual patients, measurements of drug concentrations in plasma may be the only way to elucidate clinically unexpected drug effects or to handle interaction phenomena. Knowledge of the pharmacokinetic and pharmacodynamic changes during development is a prerequisite for a correct interpretation of the concentration values. Unfortunately, the quantitative relation between kinetics and clinical effect is still relatively poorly known for many drugs in the paediatric age groups. Apart from the pharmacokinetic informative value, therapeutic drug monitoring also has some merit as an aid to the physician in explaining to the patient and the parents why the drug should be taken as instructed. This may improve compliance.