MONDAY, May 6, 2019 (HealthDay News) -- As if using cocaine or methamphetamines isn't risky enough, new research shows a sharp spike in urine drug tests that are positive for those drugs and the powerful synthetic opioid fentanyl.

The findings could provide insight into steeply rising rates of cocaine- and methamphetamine-related overdoses in the United States.

For the study, researchers analyzed data on one million urine drug tests taken in various medical settings. The investigators found that between January 2013 and September 2018, the presence of fentanyl in urine drug tests that were also positive for cocaine or methamphetamine rose 1,850% and 798%, respectively.

Those statistics suggest that increases in cocaine- and methamphetamine-related overdoses may be related to fentanyl either being added to those drugs or used at the same time, according to the authors of the study published online recently in JAMA Network Open.

Research published just last week came to similar conclusions, but from a different angle: Nearly three-quarters of cocaine-involved deaths in 2017 also involved opioids, as did about half of deaths involving psychostimulants such as meth. Synthetic opioids -- fentanyl, most prominently -- often played a key and deadly role, researchers from the U.S. Centers for Disease Control and Prevention found.

In the latest study, the urine tests were ordered by health care providers in numerous areas of medicine, including pain management, primary care, addiction treatment, behavioral health, obstetrics and gynecology, and multi-specialties.

Positive results for cocaine or methamphetamine with non-prescribed fentanyl were seen across all of them, suggesting abuse is happening in many care settings, the researchers noted.

"The increasingly common concurrent use of fentanyl with cocaine or methamphetamine may help explain the recent sharp increases in overdose deaths involving stimulants," said study co-author Bob Twillman. He is a consultant with the drug testing company Millennium Health, based in San Diego.

"It is still undetermined if these combinations are created by dealers or users, and if by users, if this simply reflects a shift from heroin to fentanyl as the opioid being used," he added in a company news release.

"Clinicians and patients both should be aware of the potential consequences of fentanyl exposure, knowingly or unknowingly, and take the necessary steps to maximize patient safety," Twillman concluded.

More information

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