Opioid prescribing restrictions and opioid use among the Louisiana Medicaid population

Background: Most states in the U.S. have enacted prescription opioid quantity limits to curb long-term opioid dependency. While several studies of these policies find reductions in subsequent prescriptions, others find mixed results in reducing overall opioid prescriptions and prescription length. Our objective was to examine three opioid restriction policies implemented in Louisiana Medicaid: (1) a 15-day quantity limit for opioid-naive acute pain patients, (2) a subsequent further reduction to a 7-day quantity limit and a Morphine Milligram Equivalent Dosing (MME) limit of 120mg per day, and (3) a final reduction in daily MMEs to 90mg per day. Methods: Using interrupted time series (ITS) models with Medicaid pharmacy claims data, we estimated changes in trends of opioid prescription fills associated with opioid restriction policies in Louisiana Medicaid. Outcomes of interest included average opioid prescription length, average MMEs per day, and the likelihood that an opioid-naive beneficiary who received their first opioid prescription filled a second prescription within 30 or 60 days of their initial fill. Results: 15-day and 7-day opioid prescription quantity limits were associated with a 0.720 and a 0.401 day reduction in average opioid prescription lengths. 7-day limits were associated with a 2.7 and a 3.0 percentage point reduction in the likelihood of a second opioid prescription fill within 30 or 60 days of the initial fill. The 120mg per day MME limit was associated with a 0.80 MMEs per day reduction in average daily MMEs. Further restricting daily MMEs to 90mg per day had no statistically significant association with average daily MMEs. Conclusion: These findings suggest that efforts to limit opioid exposure through the implementation of prescrip-tion quantity limits and MME restrictions in Louisiana's Medicaid program were successful and are likely to be associated with a reduction in future opioid dependency among the state's Medicaid population.