Cost savings were not associated with an increase in adverse drug events.
A therapeutic exchange initiative from lisdexamfetamine to amphetamine/dextroamphetamine extended-release (ER) led to a significant decrease in the overall costs of long-acting stimulant medications, according to the results of a poster1 presented at the American Society of Health-System Pharmacists 2022 Midyear Clinical Meeting, held December 4 to 8 in Las Vegas, Nevada.
Researchers conducted a single-center, retrospective cohort study at a 55-bed rural pediatric and adolescent behavioral health facility. Participants were between ages 5 and 17 and were admitted to the acute program and residential treatment center. A Pharmacy and Therapeutics Committee developed a therapeutic interchange chart of equivalent doses for both medications, and a six-month transitional period was allotted before postimplementation data were collected.
The primary study outcomes were the difference in cost per patient day for long-acting amphetamine stimulants and adverse drug events that affected quality of patient care. The secondary outcome was determining if there was a significant difference in prescribing patterns, based on doses per patent for day, for immediate-release and extended-release stimulants.
After the initiation of a long-acting amphetamine therapeutic interchange, the cost per patient day decreased by 94% ($3.09 vs $0.18) with no change in adverse drug events pre- or post-implementation. Doses of immediate-release stimulants per patient day increased by 86% overall, with specific increases of 79% for dexmethylphenidate and 124% for amphetamine/dextroamphetamine—both significant increases.
There was no statistically significant difference in extended-release stimulant doses per patient day, with a decrease of 12% overall. Doses of lisdexamfetamine decreased by 100% — a significant decrease, per researchers — while methylphenidate ER and amphetamine/dextroamphetamine ER significantly increased by 77% and 336%, respectively.
“Implementation of a therapeutic interchange of lisdexamfetamine to amphetamine/dextroamphetamine ER significantly decreased long-acting amphetamines stimulant medication costs with no difference in [adverse drug events],” the researchers concluded. “Further evaluation of the doses and cost per patient day would be called for to determine if a change from extended-release to immediate-release formulations are associated with equivalent therapeutic outcomes.”