Rise, and pronounced regional variation, in methylphenidate, amphetamine, and lisdexamfetamine distribution in the United States

BACKGROUND: The prescription stimulants methylphenidate, amphetamine, and lisdexamfetamine are sympathomimetic drugs with therapeutic use. They are designated in the United States as Schedule II substances, defined by the 1970 Controlled Substances Act as having a “high potential for abuse”. Changing criteria for the diagnosis of Attention Deficit Hyperactivity Disorder in 2013 and the approval of lisdexamfetamine for binge eating disorder in 2015 may have impacted usage patterns. This report compared the pharmacoepidemiology of these stimulants in the United States from 2010–2017. METHODS: Distribution of amphetamine, methylphenidate, lisdexamfetamine were examined via weights extracted from the Drug Enforcement Administration’s (DEA) Automated Reports and Consolidated Ordering System (ARCOS). Median stimulant Daily Dosage per patient was determined for a regional analysis. The percent of cost and prescriptions attributable to each stimulant and atomoxetine in Medicaid from the “Drug Utilization 2018 - National Total” from the Centers for Medicare and Medicaid was determined. RESULTS: There was a rise in amphetamine (+67.5%) and lisdexamfetamine (+76.7%) from 2010–2017. The change in methylphenidate (−3.0%) was modest. Persons/day stimulant usage was lower in the West than in other US regions from 2014-2017. There was a negative correlation (r(48) = −0.43 to −0.65, p < .05) between the percent Hispanic population per state and the Daily Dosage/population per stimulant. Methylphenidate formulations accounted for over half (51.7%) of the $3.8 billion reimbursed by Medicaid and the plurality (45.4%) of the 22.0 million prescriptions. Amphetamine was responsible for less than one-fifth (18.4%) of cost but one-third of prescriptions (33.6%). Lisdexamfetamine’s cost (26.0%) exceeded prescriptions (16.3%). CONCLUSION: The rising amphetamine and lisdexamfetamine distribution may correspond with a rise in adult ADHD diagnoses. Regional analysis indicates that stimulant distribution in the West may be distinct from that in other regions. The lower stimulant distribution in areas with greater Hispanic populations may warrant further study.