The relationship between state prescription drug monitoring program characteristics and controlled substance dispensing to medicaid beneficiaries


      Prescription Drug Monitoring Programs (PDMPs) have been enacted by several states to combat the abuse and diversion of controlled substances (CS). The study objective is to measure the impact of state PDMP characteristics on the dispensing of opioids and benzodiazepines to Medicaid beneficiaries.


      Medicaid dispensing and reimbursement data for each state (1990-2011) was obtained from the Medicaid Drug Rebate Program. Opioid and benzodiazepine prescriptions dispensed were isolated from the data and standardized to morphine milligram equivalents (MMEs) and diazepam milligram equivalents (DMEs), respectively. Data was merged with state PDMP characteristics obtained from the National Alliance of Model State Drug Laws and several potential explanatory variables were identified; including, operational program, compulsory provider participation, interstate data sharing, and proactive notification of potential abuse. A random effects model using GLS regression was employed to generate estimates of the impact of state PDMP characteristics over time on MMEs dispensed of Schedule II opioids (CII), dispensing of Schedule III opioids (CIII), and DMEs of benzodiazepines. MMEs, DMEs, and Medicaid reimbursement dollars per MME dispensed were log transformed.


      States with operational PDMPs dispensed on average 0.29 fewer logged MMEs of CII opioids (p<0.05). States with PDMPs housed in law enforcement agencies dispensed 0.11 more logged MMEs of CII opioids (p<0.05) on average and a 1-unit increase in Medicaid reimbursement resulted in 0.39 more logged MMEs of CII opioids dispensed (p<0.001). States with PDMP interstate data sharing dispensed 0.11 more logged MMEs of CII opioids (p<0.05). Results for CIII opioids and benzodiazepines were similar.


      States with operational PDMPs dispense fewer CII and CIII opioids, and benzodiazepines, to Medicaid patients. The amount of Medicaid reimbursement and data sharing with other states is associated with increased dispensing, but compulsory PDMP use and proactive reporting to health providers were not found to impact dispensing.