OBJECTIVES: To describe trends in utilization and expenditures of biologic Disease Modifying Anti-rheumatic drugs (DMARDs) in the Medicaid outpatient pharmacy program from 2007 to 2014 and to assess the impact of the 2010 Affordable Care Act (ACA) and 2011 FDA safety communications about anti-tumor necrosis factor (TNF) drugs on the utilization of biologic DMARDs. METHODS: Medicaid drug utilization data were collected from Centers for Medicare & Medicaid Services. Biologic DMARDs and national drug codes were collected from the Food and Drug Administration (FDA) databases. An interrupted time series analysis was conducted to assess the association of the ACA and FDA safety communications and the utilization of biologic DMARDs. RESULTS: The Medicaid outpatient pharmacy utilization for biologic DMARDs increased from 11,187 claims in first quarter of 2007 to 64,684 in the fourth quarter of 2014. The highest utilization occurred in the second quarter of 2010 (104,996 claims). The Medicaid expenditures of biologic DMARDs increased from $21.9 million in the first quarter of 2007 to $202.4 million in the fourth quarter of 2014. ACA led to an increase of 17.4% in the number of anti-TNF claims per quarter in the Medicaid outpatient pharmacy program. After controlling for the effect of ACA, the 2011 FDA safety communication was significantly associated with a decrease in anti-TNF utilization (p<0.001). In addition, the FDA anti-TNF safety communication was significantly associated with an increase in the utilization of non-anti-TNF (p<0.001). CONCLUSIONS: The utilization of biologic DMARDS in the Medicaid outpatient pharmacy program significantly changed over time. The utilization of biologic DMARDS was higher post- enactment of the ACA compared to the period pre-ACA. Likewise, the utilization of Anti-TNF biologics significantly increased after the implementation of the ACA and decrease following the 2011 FDA safety communication.