Towards evidence-based pharmacotherapy in children.

In daily practice, it is difficult to find a registered drug for children, because about 70% of the drugs prescribed in children are not studied, off-label or unlicensed in this age group. Clinical trials have usually been performed in adults, and then in daily practice dosages are adjusted for children without proper studies in that age group. In some countries, national formularies are being established to overcome the existing variance in prescribing between physicians. Complicating factors in finding the correct dosage for children include the heterogeneity between different age groups in the developmental stages of the organs influencing the absorption, distribution, metabolism, and excretion as well as differences in body composition during growth. Growth may also influence the effects and adverse effects of a drug used in a child. For oral administration of drugs in children, the bioavailability, the taste, the composition, and the absence of toxic ingredients for that age group are additional important factors. The EU has recently introduced legislation to stimulate the pharmaceutical industry to investigate the pharmacological effect and safety of new medicines in children. In response to this legislation, research networks are being established to provide the optimal infrastructure for pediatric drug investigation. The goals of this paper are to review the current problems in daily practice and to address the needs for evidence based pharmacotherapy in children.