Two thirds of opioid overdose deaths in 25 states also involved cocaine, methamphetamine or a benzodiazepine
CDC surveillance, January to June 2018: illicitly made fentanyl was in about two thirds of opioid deaths, and "62.6% of all opioid deaths co-occurred with at least one common nonopioid drug" (cocaine, methamphetamine or benzodiazepines).
Reasonable evidence with real limitations. how we score evidence
Caveat on this rating: Twenty five states, six months, and "presence" means detected at death, not cause. The decrease reported was small and the authors do not claim a trend.
The question "is it okay to mix" has a public health answer in the surveillance data: most opioid deaths are already mixtures.
Significant findings
Gladden and colleagues (MMWR, 2019) describe opioid overdose deaths in 25 states participating in the CDC's State Unintentional Drug Overdose Reporting System, comparing January to June 2018 with the previous half year. The background: "From 2013 to 2017, the number of opioid-involved overdose deaths (opioid deaths) in the United States increased 90%, from 25,052 to 47,600. This increase was primarily driven by substantial increases in deaths involving illicitly manufactured fentanyl (IMF) or fentanyl analogs mixed with heroin, sold as heroin, or pressed into counterfeit prescription pills."
The findings: "overall opioid deaths decreased 4.6%"; decreases were in prescription opioid deaths without illicit opioids; and "IMF deaths, especially those with multiple illicit opioids and common nonopioids, increased. Consequently, IMF was involved in approximately two-thirds of opioid deaths during January-June 2018. Notably, during January-June 2018, 62.6% of all opioid deaths co-occurred with at least one common nonopioid drug."
The nonopioid drugs counted were cocaine, methamphetamine and benzodiazepines, detected in the person who died. The report's conclusion: efforts must "address polysubstance misuse with opioids."
Worth asking
Two things this report establishes. Counterfeit pills, including ones sold as Xanax or oxycodone, may be fentanyl; the report says so in its first paragraph. And the deaths are mostly combinations, not single drugs. If you take a prescribed benzodiazepine or stimulant and also use cocaine or pills from outside a pharmacy, the relevant number is not the interaction between your two drugs but the fentanyl you did not know was there. Fentanyl test strips and naloxone are the practical questions.
Source
Changes in Opioid-Involved Overdose Deaths by Opioid Type and Presence of Benzodiazepines, Cocaine, and Methamphetamine - 25 States, July-December 2017 to January-June 2018 — Gladden RM, O'Donnell J, Mattson CL, Seth P (2019)
Regulator or national health body
Read the source: https://doi.org/10.15585/mmwr.mm6834a2
DOI: 10.15585/mmwr.mm6834a2
How this was scored
- Study design
- Cross-sectional study / survey
- Funding
- No external funding
- Published in
- Regulator or national health body
- Sample size
- not recorded
- Preregistered
- not recorded
- Conflicts disclosed
- Yes
- Independent of proponent
- not recorded
- Retracted
- No
Read the full scoring rubric, including what it can't tell you.
Published September 21, 2026.
Questions
How strong is the evidence behind this?
veisund rates this source "moderate evidence". Reasonable evidence with real limitations. It scores 58 out of 100 on our published rubric. One caveat travels with that badge: Twenty five states, six months, and "presence" means detected at death, not cause. The decrease reported was small and the authors do not claim a trend. The score is calculated from recorded facts about the source — study design, funding, publication venue, sample size, preregistration — not typed in by an editor.
What is the source for this?
Changes in Opioid-Involved Overdose Deaths by Opioid Type and Presence of Benzodiazepines, Cocaine, and Methamphetamine - 25 States, July-December 2017 to January-June 2018 — Gladden RM, O'Donnell J, Mattson CL, Seth P (2019). Published in: Regulator or national health body. DOI: 10.15585/mmwr.mm6834a2. The full source is linked on this page so you can read it yourself.
Who paid for this research, and does that matter?
Study design: Cross-sectional study / survey. Funding: No external funding. Independence from the proponent is not recorded. Industry sponsorship is one of the most reliably measured biases in medicine, which is why funding carries real weight in the score rather than sitting in a footnote.
Is this medical advice?
This is information to bring to your prescriber, not medical advice and not a reason to change anything on your own. Nothing here is an instruction to stop or reduce a medication. If you are in crisis, call or text 988.
This is information to bring to your prescriber, not medical advice and not a reason to change anything on your own. Nothing here is an instruction to stop or reduce a medication. If you are in crisis, call or text 988.