Objectives: In the light of the undesired effects that unlicensed and off-label drug use might have, it is necessary to study the determinants affecting the prescribing of such drugs. Prescription of drugs to children younger than the minimum licensed age may carry the highest risk of adverse reactions. To obtain insight into the factors that affect prescription of drugs to children below the minimum licensed age, we conducted a population-based case-control study.
Methods: The case-control study was nested in a cohort of 13,426 children aged 0-16 years, who were registered in the Integrated Primary Care Information (IPCI) project, a longitudinal observational general practitioners' database in the Netherlands. "Cases" were children who received a drug prescription for which they were below the minimum licensed age. To each case we matched up to four controls based on GP practice and patient age. As potential risk factors we evaluated the use of health care resources, and acute and chronic morbidity.
Results: We identified 447 cases who were matched to 1355 controls. The cases consulted their GPs significantly more often during the preceding half year, had more drug prescriptions, and had more specialist referrals than the controls. Respiratory diseases were the most important determinants for the prescription of drugs to children below the minimum licensed age. In adolescents, migraine and other headaches were the most important reasons.
Conclusions: This study showed that children suffering from respiratory disease or migraine have the highest risk of receiving a drug prescription for which the patient is below the minimum licensed age. Regulatory authorities and the pharmaceutical industry should be stimulated to improve the evaluation of drug efficacy and safety in children.