Reazioni avverse da uso off-label dei farmaci nei bambini. Un'esperienza pilota di valutazione prospettica

Recently published studies examining the extent of off-label drug prescribing in various European paediatric wards have reported that such usage is widespread and is particularly high in Italy. So far, however, no studies have investigated the extent to which adverse reactions (ADRs) due to off-label drug use occur in Italy. To evaluate the risk associated with off-label drugs use in paediatric in-patients, a prospective surveillance was carried out in a paediatric ward of a teaching hospital over a nine month period. Forty-one children (mean age: 7.2 yrs, 58% male) suffered from ADRs out of a study population of 1619 patients. In 29 children the ADRs were due to hospital drug therapies, in 12 to medicines administered in the community. Urticaria (11 cases), vomiting and rash (5 each) and tremor (4) were the most common ADRs. The drugs most frequently associated with ADRs were salbutamol (5 cases) and amoxicillin/clavulanic acid (4). Eight ADRs (20%) were classified as severe. Off-label drug prescriptions were responsible for 38% of in-patient ADRs and for 42% of the out-patient ADRs that led to hospitalisation. The use of drugs not licensed for paediatric use (8 cases), or used for indications not reported in the summary of product characteristics (6) were the off-label categories most frequently associated with ADRs. Drugs used for endocrinology diagnostic tests were responsible for one third of ADRs due to off-label uses. The results of this study suggest a high risk of ADRs associated with off-label prescribing in children, both in the hospital and in the community. This pilot study also demonstrates the feasibility of ah ADR monitoring system that could take into account important issues relating to rational drug prescribing in paediatric patients. Continuation of the study, also in a community setting, is required for a comprehensive risk assessment of off-label drug interventions in children because the lack of paediatric labelling does not prevent prescription of an approved drug for ah unapproved use.