Researchers in Missouri are taking a closer look at the brain regions that stop working during a fentanyl overdose, hoping to identify new targets for treatment as the drug continues to drive more than 81,000 overdose deaths in the United States every year.

A $577,531 grant from the Department of Health and Human Services is funding the work, which focuses on two brainstem areas responsible for controlling breathing. Fentanyl's primary mechanism of death is respiratory depression: it essentially tells the brain to stop breathing. Yet most research into opioid addiction and overdose has focused on brain regions tied to addiction rather than the ones that actually kill people.

The research team will analyze brain tissue from 40 people who died of fentanyl overdoses and 40 matched controls, using newer molecular techniques that can read gene activity and chromatin accessibility at the level of individual cells. The goal is to build the first detailed map of what is happening genetically inside those brainstem regions at the moment of overdose, and to identify specific genes that could be targeted by future drugs. The study will also examine cases where xylazine, a veterinary sedative increasingly found alongside fentanyl in the drug supply, was present, since that combination poses added risks for responders and survivors.

Fentanyl was involved in more than 92 percent of the roughly 81,000 opioid overdose deaths recorded in 2023, according to the grant, and the pace of deaths has not slowed meaningfully despite wider distribution of the overdose-reversal drug naloxone. Researchers hope that understanding the precise cellular mechanisms behind respiratory failure could eventually lead to treatments that work differently than naloxone, or that could help people who are harder to revive.

The project fits into a broader push to fund basic science on opioids alongside clinical interventions. Similar federally funded addiction research has included efforts to train rural doctors in Ohio and test overdose prevention programs for women leaving prison in Kentucky. The Missouri brainstem study is more foundational: it aims to understand the biology well enough that future clinical solutions become possible.

Once the cellular data is assembled, the team plans to cross-reference it with large genetic studies of overdose deaths to identify which inherited variations may make some people more vulnerable, and to flag gene-drug combinations worth testing in preclinical trials.