This Week’s Focus: Fentanyl Overdoses

This week, the NDEWS Weekly Briefing focuses on fentanyl overdoses. The National Institute of Technology Rapid Drug Analysis & Research (RaDAR) newsletter reported on September 15, 2025, that fentanyl was the top compound detected within samples collected in August 2025. It furthermore stated that fentanyl was the top compound detected along the East Coast and the second most detected compound on the West Coast, after methamphetamine.

Our NDEWS Special Report focuses on fentanyl-related EMS encounters occurring at specific times of the day. The findings of the report are displayed through a heat map that indicates the most frequent times EMS personnel reported fentanyl-related overdoses in the US.

NDEWS was recently featured in the Fall 2025 issue Explore published by University of Florida Research. The article dives into background, mission and work of NDEWS. In addition, it highlights direct quotes from NDEWS Director Linda Cottler, Co-Director Joseph Palamar, Co-Investigator and Sentinel Site Director Bruce Goldberger, along with NIDA's Deputy Director Wilson Compton. To view the full article, click here.

Out of 123,738 EMS encounters for fentanyl-related overdoses from January 1, 2024 to August 31, 2025, the data shows a slightly later peak in EMS encounters for fentanyl-related overdoses between 17:00 and 21:59, with Fridays recording the highest number of EMS encounters by day of the week. To view the entire Special Report from the weekly briefing, click here.

Click here to learn more about NDEWS Hotspot Alerts

A recently published study in the International Journal of Drug Policy by Shover et al. examines the purity of illegally manufactured fentanyl (IMF). 1,763 samples from a community-based drug checking program at four different locations across Los Angeles were analyzed using observed mass spectrometry. The results of the study found a high variation in the purity of IMF among the samples sold as fentanyl, even among samples acquired on the same day and at the same location. Read the full study here.

A currently in press, journal pre-proof case series available online in AJPM Focus by Buchanan, and featuring NDEWS SAG member Alex Krotulski, looks at the possibility of strychnine as an emerging adulterant in the fentanyl supply. Historically, strychnine was utilized as a tonic, laxative, rodenticide, and adulterant in cocaine, heroin, and methamphetamine. The data for the case series were gathered from the ToxIC Fentalog Study (2020-2025). Four cases in 2023 from Denver, Colorado, showed signs of strychnine, which indicates a reappearance in its use as an adulterant. Read the case series here.

A recently published study in Science Advances by Shi et al. introduces a screening platform that uses a machine learning classifier and a multilayer molecular network to select and annotate fentanyl compounds using mass spectrometry (MS). The screening platform, named Fentanyl-Hunter, scanned 772 fentanyl spectra and achieved an F1 score of 0.868, and its network covers 87% of known fentanyl derivatives. The authors note this screening platform has the potential to enhance public health surveillance, forensic investigations, and environmental monitoring. Read the full article here.

A published study in Drug Testing & Analysis by Ballotari et al. focused on the development and validation of ultra-performance liquid chromatography-mass spectrometry method of detection and quantification of fentanyl, nonpharmaceutical fentanyl, xylazine, and the semiquantitative detection of nitazenes in post-mortem hair samples. A collection of 250 post-mortem hair samples were tested, with fentanyl and its metabolites being detected in 52%, while xylazine was detected in 19.2% of the samples analyzed. The developed method showed promise for rapid chromatographic separation and sensitive detection of the studied compounds. Read the full article here.

Are you committed to advancing the science of substance use and public health? The University of Florida’s NIDA-funded T32 Training Program offers predoctoral and postdoctoral scholars an exceptional opportunity to launch impactful research careers focused on NDEWS!

What We Offer:
- Interdisciplinary training at the intersection of addiction science, epidemiology, and surveillance
- Mentorship from leading UF faculty in epidemiology, public health, psychology, medicine, and more
- Hands-on research with landmark and important NIH-funded projects and access to rich data
- Career development support, including grant writing, publishing, and professional networking
- A collaborative, inclusive research community committed to reducing the burden of substance use

Eligibility:
- US citizens or permanent residents
- Interested in a PhD in Epidemiology, or early-stage postdoctoral fellows
- Demonstrated interest in substance use, addiction, or public health research

Location: Gainesville, Florida — a dynamic hub for scientific innovation with high quality of life and low cost of living.

📅 Date: Friday, September 26, 2025

🕑 Time: 1:30 pm - 2:30 pm ET

📍 Location: Online 

📅 Date: Monday, September 29, 2025

🕑 Time: 3:00 pm - 4:00 pm ET

📍 Location: Online 

📅 Dates: Tuesday, October 7, 2025

🕑 Time: 8:00 am - 10:30 pm ET

📍 Location: Online 

📅 Dates: Thursday, October 9, 2025

🕑 Time: 11:00 am - 12:30 pm ET

📍 Location: Online 

📅 Dates: Friday, October 10 & 17, 2025

🕑 Time: 10:00 am - 5:00 pm ET

📍 Location: Online 

The NDEWS Weekly Briefing curates emerging data and findings from across the Early Warning Network, which includes three core components: our Scientific Advisory Group (SAG), comprised of national experts and federal partners; our Sentinel Site Directors (SSDs), who lead local surveillance in key geographic regions; and our Community-Based Health Experts, who provide on-the-ground insights from populations most impacted by drug trends. Together, these contributors generate timely, multidisciplinary and impactful information, ranging from peer-reviewed research findings to local surveillance data. These contributions inform public health and research communities.

More about The NDEWS Early Warning Network
- Issue 230: Early Warning in Action — Insights from the NDEWS Early Warning Network
- Issue 234: Early Warning in Action — Insights from the NDEWS Early Warning Network

You can share the NDEWS Weekly Briefing with friends, colleagues, and others who would benefit from information on recent and relevant news, articles, and data related to novel drug trends in the US and globally by clicking here.

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If you miss or want to learn more about NDEWS Original Content, you can find our archived content on the NDEWS website:

     • NDEWS Hotspot Alerts using substance-related EMS data
     • NDEWS Rapid Street Reporting (RSR) survey data reports
     • NDEWS Web Monitoring Team Reddit Alerts
     • NDEWS Sentinel Site Reports
     • Previous issues of the NDEWS Weekly Briefings

The Weekly Briefing is a newsletter published each week by the National Drug Early Warning System (NDEWS) Coordinating Center, which is funded by the National Institute on Drug Abuse (U01DA051126) to the University of Florida (MPI: Cottler (contact), Co-Is: Goldberger, Nixon, Striley), NYU Langone Health (MPI: Palamar), and Florida Atlantic University (Co-I: Barenholtz). Any item may be reproduced provided the source is acknowledged.