(HealthDay)—An increasing number of urine drug test (UDT) results positive for cocaine or methamphetamine are also positive for nonprescribed fentanyl, according to a study recently published in JAMA Network Open.

Leah LaRue, Pharm.D., from Millennium Health in San Diego, and colleagues analyzed one million patient specimens from January 2013 through September 2018. These specimens were submitted for UDTs by as part of routine care at health care practices across the country (including substance use disorder treatment centers, pain management practices, primary care practices, behavioral health practices, obstetrics and gynecology practices, and multispecialty groups). Liquid chromatography-tandem mass spectrometry was used to analyze UDT for benzoylecgonine (cocaine metabolite), methamphetamine, fentanyl, and norfentanyl.

The researchers found that positivity rates for nonprescribed fentanyl among the cocaine-positive results increased significantly, from 0.9 percent in 2013 to 17.6 percent in 2018, an increase of 1,850 percent. There was also an increase in positivity rates for nonprescribed fentanyl among the methamphetamine-positive results, from 0.9 percent in 2013 to 7.9 percent in 2018, a 798 percent increase.

"Clinicians need to be aware that patients presenting for treatment of suspected or may have been exposed, knowingly or unknowingly, to multiple substances, including the combination of stimulants and opioids," the authors write.

Several authors disclosed financial ties to Millennium Health, which funded the study.

More information: Abstract/Full Text

Journal information: JAMA Network Open