OBJECTIVES: To explore whether Medicaid preferred drug lists (PDL) impact the utilization of restricted statin medications for Medicaid patients equally, or disproportionately impact patients treated by doctors prescribing in poor or minority neighborhoods. METHODS: A retrospective, regression-based analysis, of a pharmacy claims database and census data of the prescriber's zip-code. Post policy changes in the proportion of statin prescriptions filled for off-PDL medicines were examined in six states. Two non-PDL states were used as controls for underlying market dynamics. Demographics of physicians' neighborhoods (poverty and ethnicity) were used to examine the variation in prescribing based on the characteristics of physicians' areas of practice. RESULTS: The post-policy decline in the use of restricted prescriptions varied considerably, from Florida (-97%) to Texas (-65%). There was a statistically significant positive association between the magnitude of decline and the share of impoverished households and the share of the minority population in Alabama, Florida and Texas. CONCLUSION: The analysis indicates that there is considerable variation in the impact of a PDL by state, and in certain states by the degree of poverty or diversity in the neighborhood. This could imply due to the PDL, in poorer and more ethnically diverse neighborhoods, fewer patients receive the restricted medication by prior authorization, and more patients experience a disruption in their medication regimen and any resultant unintended consequences. This is an area worthy of exploration, as the dual eligibles transition into Medicare part D and may experience changes in formulary.