• Posted August 27, 2026

Illegal Fentanyl Use Double That For Medical Purposes, With High Risk Of OD, Study Finds

Illegal use of the powerful synthetic opioid fentanyl is more than double its use for medical purposes in the United States, a new study has found.

More than 7 of 10 people whose urine tested positive for fentanyl had not been prescribed the drug, but were using it illicitly, researchers report in the September issue of the journal eClinicalMedicine.

“Finding that illicit use has reached 70% among all fentanyl users is a surprise," said senior researcher Ping Zhang said in a news release. He’s a professor of computer science and engineering and biomedical informatics at Ohio State University.

Results also showed that illicit users were three times more likely to suffer an overdose than people given fentanyl in the hospital or prescribed the drug.

Fentanyl is 50 times stronger than heroin and 100 times more powerful than morphine, researchers said in background notes. Even small doses can cause a fatal overdose, and synthetic opioids including fentanyl have been linked to nearly 70% of U.S. overdose deaths.

But fentanyl also plays a critical role in medicine for managing severe pain, particularly in patients with advanced cancer and those recovering from surgery, researchers noted.

“Fentanyl is a big problem, but we don’t actually know how serious illicit drug use is compared to medical use,” Zhang said.

To try to answer that question, researchers analyzed data for nearly 300,000 people whose urine tested positive for fentanyl use between 2015 and 2023, out of more than 300 million patients treated during that time. The records came from a national U.S. healthcare database that covers all 50 states.

About 71% of those who tested positive had been using fentanyl illicitly, more than twice the 29% who had been given fentanyl for medical purposes, the study said.

Analysis also showed that people using fentanyl illegally were three times as likely to have an overdose or become addicted to the drug.

“These patterns indicate that illicit-source fentanyl remains a significant and growing threat to public health nationwide,” the researchers wrote.

They next plan to analyze whether medical use of fentanyl might increase risk of illicit use.

More information

The U.S. Centers for Disease Control and Prevention has more on fentanyl.

SOURCES: Ohio State University, news release, Aug. 24, 2026; eClinicalMedicine, September 2026