Suspected ADRS in Children

SUSPECTED ADRS IN CHILDREN

There has been significant public interest expressed in the safety of medicines used in children; particular concern surrounds the safety of medicines which are not specifically licensed for use or are used ‘off label’ (i.e. for unlicensed indications) in this patient group (Wells, 1996). Despite the lack of firm evidence of safety and efficacy in children, of medicines licensed for use in adults, such medicines may well be used when treating children, especially where no licensed alternatives exist. Safety and efficacy in chil-dren cannot be assumed simply based on data from studies in adults; for instance, children differ from adults in terms of their pharmacokinetics (Leeder, 1996; Reed, 1996). It is possible that the adverse reaction profile of a medicine in children may differ from that in adults, and it is therefore particularly important to collect suspected ADR reports in this area. However, it is notable that under-l8-year-olds make up around 20% of the population, but that the proportion of Yellow Card reports received for this age group was somewhat lower in 1997 and 1998 (approximately 8%).

To investigate whether unlicensed or ‘off label’ use of medicines in children was leading to adverse reac-tions, and whether such reactions were being reported, a pilot Scheme to stimulate reporting of suspected ADRs in children was set up in the Trent NHS region in September 1998; this Scheme targeted paediatri-cians and hospital pharmacists.

An analysis by the MHRA of this pilot Scheme, two years following its introduction, showed that there was an increase in the absolute numbers of hospital reports of suspected ADRs in children received from the Trent region. Since the time covered by this analysis overlapped significantly with the nationwide meningitis C vaccination campaign, it was perhaps not surprising that the majority of reports received were of suspected ADRs associated with this vaccine. However, when reports for meningitis C vaccine were excluded, it was notable that the underlying rate of paediatric reporting in the Trent region had remained relatively static between 1994 and 2000, and was comparable with national reporting rates for suspected ADRs in children; additionally a relatively low proportion (less than 30%) of reports related to serious reactions.

As a separate initiative, the MHRA collabo-rated with the British Paediatric Surveillance Unit (BPSU) (now the Royal College of Paediatrics and Child Health) on their ‘Orange Card’ reporting Scheme, where consultant paediatricians report partic-ular disorders under surveillance in children to the BPSU (Verity and Preece, 2002). In order to improve the availability of medicines licensed for use in chil-dren and to seek ways of improving reporting of paediatric ADRs, the CSM established a Paediatric Medicines Working Group in July 2000. A move towards improving the safe use of medicines in children was also undertaken in Europe and in Decem-ber of the same year a Council Resolution called on the European Commission to find solutions to the issue of inadequate medicines for children. In Septem-ber 2004, the Commission adopted the proposal for a regulation of the Council and the European Parliament on medicinal products for paediatric use, with the overall objective of improving the health of children in Europe by increasing research, development and authorisation of medicines for paediatric use. As part of the proposal, measures to increase the robustness of pharmacovigilance for paediatric medicines will be put forward and a Paediatric Working Party within the European Medicines Agency (EMEA) will be established.In recent years, the proportion of Yellow Cards received by the MHRA in under-l8-year-olds has increased marginally to 10% of all UK ADR reports received in 2004, perhaps influenced by the introduction of nurse reporting and a general increased knowledge about the Scheme. There is still room for improvement, but with the advent of the European paediatric regulation and the introduction of patient reporting in the United Kingdom, it is likely that paediatric ADR reporting will continue to increase.