The risk of PDIs in children is low, but it increases significantly with age and the number of drugs prescribed, particularly antiepileptics and immunosuppressants. The finding of a potential interaction in 0.47 % of all children in whom any medication was prescribed should not be underestimated since it means a significant risk for one child out of every 200, and it is also substantially higher in the chronically ill. Pediatricians should be aware of relevant interactions and should prevent them by therapeutic drug monitoring or appropriate clinical and laboratory monitoring.