Prevalence of contraindicated combinations amid behavioral and mental health medications filled in a pediatric population

Background: Behavioral or mental health disorders are common in children, adolescents, and young adults. Medication use is increasingly common, with few data describing drug-drug combinations in ambulatory settings. The objectives of this study were to describe the pharmaco-epidemiology of behavioral and mental health (BMH) medications among children, adolescents, and young adults in New York Medicaid and assess the prevalence of contraindicated drug pairs within this population. Methods: This observational cross-sectional study evaluated New York State Medicaid managed care and fee-for-service enrollees under 21 years of age dispensed BMH medications in 2014. Main outcomes included number of members with prescriptions filled; number filling > 1 medication prescription concurrently for ≥ 30 days (polypharmacy), and number and nature of potentially contraindicated drug pairs. Results: Of 2,430,434 children, adolescents, and young adults, 422,486 (17.4%) had a visit associated with a BMH diagnosis and 141,363 (5.8%) received one or more BMH medications. With 84 distinct medications evaluated, polypharmacy was common, experienced by 53,388 individuals (37.8% of those with a prescription filled), generating 11,115 distinct drug combinations. 392 individuals filled prescriptions for a contraindicated pair of ≥ 2 BMH medications for 30 days or longer. With ≥ 1 day overlap, 651 were exposed to contraindicated medications. The most common contraindicated pairs increased potential risk for prolonged QT interval and serotonin syndrome (n = 378 and n = 250 patients, respectively). Most combinations involved ziprasidone (3247.1 per 10,000 ziprasidone prescriptions filled). Conclusions: With nearly 6% of members dispensed a BMH medication, contraindicated drug pairs were uncommon. However, any of those combinations represent a potential risk. Clinicians should attend to the balance of potential risks and benefits before contraindicated pairs are dispensed. The methodology described could serve as a basis for monitoring such rare instances and might reduce harm.