Potential drug-drug interactions in infant, child, and adolescent patients in children's hospitals.

BACKGROUND AND OBJECTIVES Hospitalized infants, children, and adolescents are typically exposed to numerous distinct medications during inpatient admissions, increasing their risk of potential drug-drug interactions (PDDIs). We assessed the prevalence and characteristics of PDDI exposure of pediatric patients treated in children's hospitals. METHODS This retrospective cohort study included patients <21 years old hospitalized in children's hospitals throughout the United States. PDDIs were identified by using the MicroMedex DRUG-REAX system. We calculated the patients exposed to PDDIs, stratified according to the seriousness of the interaction; daily and cumulative counts of PDDI exposures; and characterization of the cited potential adverse effects. RESULTS Of 498 956 hospitalizations in 2011, 49% were associated with ≥1 PDDI, with a "contraindicated" PDDI occurring in 5% of all hospitalizations, a "major" PDDI present in 41%, a "moderate" PDDI in 28%, and a "minor" PDDI in 11%. Opioids were involved in 25% of all PDDIs, followed by antiinfective agents (17%), neurologic agents (15%), gastrointestinal agents (13%), and cardiovascular agents (13%). One-half of all PDDI exposures were due to specific drug pairs occurring in ≤3% of patients per hospital day. The most common potential adverse drug events included additive respiratory depression (in 21% of PDDIs), bleeding risk (5%), QT interval prolongation (4%), reduced iron absorption/availability (4%), central nervous system depression (4%), hyperkalemia (3%), and altered diuretic effectiveness (3%). CONCLUSIONS Exposure to PDDIs is common among hospitalized children. Empirical data are needed to determine the probability and magnitude of the actual harm for each specific PDDI, particularly for less common drug pairs.