Fentanyl Use Declines in 2024 but People Who Use Fentanyl are Increasingly Using Heroin, Methamphetamine

Millennium Health Signals Report™ highlights the continued evolution of polysubstance use

SAN DIEGO--(BUSINESS WIRE)--The latest Signals Report from Millennium Health highlights that fentanyl detection in urine drug tests has fallen more than 12% from its 2022 peak but fentanyl-associated polysubstance use remains a significant and constantly evolving threat.

The analysis of more than 1.4 million urine drug testing results revealed that roughly 93% of the population using fentanyl tested positive for additional substances in 2024, with a notable 14% rise in stimulant use compared to the previous year. Similarly, data from the Centers for Disease Control and Prevention (CDC) indicate that nearly 60% of fatal fentanyl overdoses in 2023 involved stimulants,¹ a phenomenon that has been called the “fourth wave” of the overdose epidemic and further complicates public health responses.

A copy of the full report can be accessed here.

Most strikingly, heroin co-use in this population surged nearly 18% nationwide from 2023 to 2024, marking the first significant increase in nearly a decade. The heroin detection rate spiked in mid-2024 and exceeded 30% in the latter part of the year.

“While fentanyl use is falling, the rise in heroin co-use among those using fentanyl is a trend we are watching closely,” said Millennium Health Senior Vice President and Chief Clinical Officer, Angela G. Huskey, PharmD, CPE. “Coupled with the continued increases in stimulant co-use, rapid shifts like this make the illicit drug supply dangerously unpredictable. This would be especially concerning if we were to see a further increase in the use of even more deadly opioids like carfentanil,” she added.

The report also shows significant regional variations. Methamphetamine use was most common among those using fentanyl in the West (at over 78%), whereas co-use of cocaine was most common in the Northeast (at over 54%). Heroin co-detection in specimens positive for fentanyl was highest in the Midwest and South, but generally increased across all regions.

These current drug use trends are detailed in the Millennium Health Signals Report – Shifting Tides: The Continued Evolution of the “Fourth Wave” of America’s Overdose Crisis.

Data in the Millennium Health Signals Report originates from the company’s Emerging Threat Intelligence ™ (ETI) Program. “The ETI program provides real-time surveillance of drug use trends that may be leveraged by clinicians, researchers, public health officials, and policymakers to help guide efforts to address our nation’s drug overdose crisis,” said CEO, Scott Walton.

“Most importantly, our Signals Reports are more than just an academic exercise. Behind the numbers and statistics are hundreds of thousands of individuals and families who are experiencing pain, uncertainty, and—all too often—the grief that is associated with substance use disorders, overdose, and accidental poisonings. We must hold them in clear focus as we all work to further stem the tide of this evolving crisis.”

Methodology

The 2025 Millennium Health Signals Report is an analysis of urine drug testing specimens collected between January 1, 2016, and November 30, 2024. Included specimens were from patients aged 18 years or older with a substance use disorder diagnosis. Specimens were collected in health care practices located in all 50 states. More than 1.4 million urine specimens representing 458,000 unique patients are included in the analysis. Further detail on the drugs analyzed and statistical methods is provided in the report.

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1. CDCWONDER. Centers for Disease Control and Prevention. Accessed January 14, 2025. https://wonder.cdc.gov/