Rates of a potentially deadly overlap between use of nonprescribed fentanyl and use of either cocaine or methamphetamine have been increasing, a cross-sectional study of 1 million urine drug tests shows.
Leah LaRue, PharmD, of Millennium Health in San Diego, and colleagues performed the study, which sampled 1 million urine drug tests submitted by health care professionals “as part of routine care” during Jan. 1, 2013–Sept. 30, 2018. They isolated tests that were positive for either cocaine or methamphetamine – but not positive for both – and then determined how many in each group were also positive for nonprescribed fentanyl. Their analyses showed that the rate of cocaine-positive tests that also were positive for nonprescribed fentanyl increased from 0.9% in 2013 (n = 84; 95% confidence interval, 0.7%-1.1%) to 17.6% in 2018 (n = 427; 95% CI, 16.1%-19.1%), an increase of 1,850% (P less than .001). The rate of methamphetamine-positive tests that also were positive for nonprescribed fentanyl also started at 0.9% in 2013 (n = 29; 95% CI, 0.6%-1.2%) but rose to 7.9% in 2018 (n = 344; 95% CI, 7.1%-8.7%, a 798% increase (P less than .001). The study was published in.
The investigators suggested two explanations for these increases: intentional combination of drugs for “speedball effects” of combining stimulants and depressants and/or unintentional exposure on the part of users through contamination of substances. There have been increases in both cocaine-related and methamphetamine-related deaths, and the investigators of this study suspect these increases could be explained in part by overlap with opioids such as fentanyl. Part of the overdose risk inherent in these combinations is that, as the stimulant wears off, the fentanyl increasingly depresses the respiratory system, according to investigators; alternatively, opioid-naive stimulant users might be exposed to high levels of fentanyl with no opioid tolerance, which also can lead to overdose.
The study’s limitations include how samples were submitted – by health care professionals as part of routine care – and the possibility that individuals’ list of prescribed medications could have been incomplete or inaccurate such that the presence of prescribed fentanyl was counted as nonprescribed.
“The combination of nonprescribed fentanyl with cocaine or methamphetamine places an individual at increased risk of overdose,” they concluded.
SOURCE: LaRue L et al. JAMA Netw Open. 2019 Apr 26. .