Regional Trends in the Opioid Epidemic Using Safety Signals of Drug Abuse and Dependence: A Disproportionality...

The opioid epidemic, once a major concern in the United States, has escalated worldwide through three waves driven by prescription and synthetic opioids like oxycodone and fentanyl. Regional patterns of misuse and dependence remain unclear due to data heterogeneity. To address this, we compared adverse events reporting for these opioids using VigiBase.

We analyzed "drug abuse and dependence" adverse events using VigiBase, a global pharmacovigilance database containing more than 40 million Individual Case Safety Reports (ICSRs). A regional comparison of opioid-related adverse event reporting was performed, with oxycodone and fentanyl as the primary drugs and morphine and tramadol as comparators. Adverse events were defined by Standardized MedDRA Query (SMQ) criteria and cases were stratified by three periods (1990-2009, 2010-2012, 2013-2024) and regions (Americas, Western Pacific, Europe). Opioid-related death was additionally assessed as a secondary outcome. Disproportionality analysis was conducted to identify safety signals, using the reporting odds ratio (ROR). Signals were considered significant if ROR > 2, χ² > 4, and more than three reports were observed.

Oxycodone-related reports peaked in 2005 (n = 8395), 2011 (n = 10,444), and 2021 (n = 45,025), while fentanyl peaked in 2011 (n = 11,451) and 2017 (n = 32,704). The safety signals for oxycodone were found across all predefined periods in the Americas (1990-2009: ROR 4.40, n = 9102; 2010-2012: ROR 2.13, n = 2299; 2013-2024: ROR 5.20, n = 108,068), and in two periods in the Western Pacific (2010-2012: ROR 6.53, n = 81; 2013-2024: ROR 5.94, n = 1066). No signals were detected for oxycodone in Europe, and fentanyl did not meet signal criteria in any region or period in the primary analyses.

Oxycodone showed consistent safety signals in the Americas and Western Pacific. The absence of signals for fentanyl and in Europe may reflect under-reporting, highlighting the need for improved surveillance of illicit opioid use.