Since 2016, an increasing number of states have passed laws restricting the days’ supply for opioid prescriptions, yet little is known about how these laws affect patients. This study evaluates the effect of the Tennessee Prescription Regulatory Act, which was implemented on Oct. 1st, 2013 and restricted the maximum days’ supply that could be dispensed for any opioid prescription by any prescriber to 30 days, on patients receiving long-term opioid treatment.
A quasi experimental model, an interrupted time series (ITS), was used with observational data to estimate the effect of the policy on monthly patient opioid prescription outcomes. Data for this study came from the Tennessee Controlled Substance Monitoring Database between October 1st, 2012 and October 31st, 2014. The study population included patients receiving long-term opioid treatment who filled an opioid prescription in at least 4 months in the 12-month pre-policy period and received at least one prescription in the pre-policy period with a days’ supply exceeding 30 days. Three outcomes were measured each month for every patient based on their opioid prescriptions: per-prescription days’ supply per-prescription, daily morphine milligram equivalent (DMME), and total opioid prescriptions. All models controlled for individual fixed effects, age, and benzodiazepine prescriptions and utilized cluster robust standard errors to address serial correlation.
The change in law was associated with a decline in the average days’ supply by -5.30 days (95% CI: -5.64, -4.96), and number of prescriptions by -1.3% (95% CI: -3%, -0.07%), but an increase in the average DMME by 1.41 (95% CI: 0.37, 2.45).
Prescribers responded to the Addison Sharp Prescription Regulatory Act by significantly decreasing the days’ supply in opioid prescriptions among current patients receiving long-term opioid treatment who had at least one prescription exceeding the maximum days’ supply set by the law in the pre-policy period.

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