Date of Award


Degree Type


Degree Name

Master of Science in Pharmaceutical Sciences


Biomedical and Pharmaceutical Sciences

First Advisor

Xuerong Wen


Background: Risks of morbidity and mortality may arise when prescription stimulants are used in combination with prescription central nervous system (CNS) depressants. The RI Prescription Drug Monitoring Program (PDMP) captures all prescriptions for schedule II to IV, as well as information on certain schedule V medications.

Objective: This study examines the pattern of using a combination of controlled substance prescription CNS stimulants with CNS depressants in RI. We also seek the predictors of concomitant use of these two drugs classes in patients.

Methods: This was a cross-sectional study using de-identified data from the RI PDMP in 2015. We included all patients who filled a prescription for stimulants or CNS depressants. Medications that are not in these two study drug classes were excluded. The outcome of interest was concomitant use of stimulants and CNS depressants, which was defined as patients who filled any stimulants and any depressants with at least 60 days of combined fill and less than 15 days’ gap in filling. Demographic characteristics of patients were used in the statistical analyses to identify the predictors of concomitant use of stimulants and depressants.

Results: In the complete RI PDMP data set, there was a total 409,740 patients who filled 2,516,314 prescriptions of schedule II to V medications. The patients using both stimulants and CNS depressants tended to be younger females, which used private pay (cash) more frequently than their male counterparts. Patients in the stimulants and CNS depressants cohort were older women who used commercial pay type at a higher percentage than their counterparts in the stimulants only cohort. A difference existed in the percent of patients that filled an average days’ supply of less than or equal to 30 days compared with greater than 30 days, between those who take both prescription controlled substance stimulants and depressants chronically compared with those who fill only stimulants. In hypothesis 3, patients in the Attention Deficit Hyperactivity Disorder cohort were younger with a lower percentage average daily dose (less than or equal to 25 milligrams) of stimulant, more likely to be of male sex, and use commercial insurance as the primary pay type compared to the usage of stimulants in the stimulants and CNS depressants cohort.

Conclusion: The prevalence of chronic concomitant therapy of stimulants with CNS depressants was associated with prescribing longer days of supply and higher dose of stimulants. The most prevalent pay type of all cohorts was commercial insurance.



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