BACKGROUND : Between 2012 and 2017, the United States dramatically reduced opioid prescribing rates. While this may be appropriate given the opioid epidemic, there has been little research to guide the clinical practice of discontinuing patients from opioid medications and opioid death rates have continued to increase. OBJECTIVE : To determine the relationship between time to opioid discontinuation and the risk of an opioid-related emergency department visit or hospitalization among high dose opioid users. METHODS : We applied Cox proportional hazard models to 2013-2017 Medicaid claims data to research this relationship. METHODS : Medicaid beneficiaries in Vermont who filled prescription opioids at high daily doses (at least 120 morphine milligram equivalents) for 90 or more consecutive days and who subsequently discontinued opioid prescriptions (n = 494). METHODS : The outcome was an opioid-related adverse event defined as an emergency department visit or hospitalization with a primary or secondary diagnosis of opioid poisoning or substance use disorder. RESULTS : The median length of time to discontinuation was 1 day indicating that half of patients had no dose reduction prior to discontinuation. 86% of patients discontinued within 21 days (considered rapid tapering in recent clinical guidelines). 49% of members had an opioid-related hospitalization or emergency department visit. After controlling for sociodemographic and clinical factors, each additional week of discontinuation time was associated with a 7% reduction in the probability of having opioid related adverse event (p < 0.01). Although 60% of members had a diagnosed substance use disorder prior to tapering, <1% of beneficiaries were transitioned onto an opioid use disorder medication. CONCLUSIONS : Faster rates of opioid tapering were associated with a greater probability of adverse events and many patients discontinued opioids suddenly, with no dose reduction. Additional clinical guidance, research, and interventions are needed to ensure that patients' opioid prescriptions are discontinued safely.