When someone buys a pill or powder sold as fentanyl, they are often buying a mix. A new federal study shows how much else is in there, and how fast the list is growing. For families looking for drug rehab in Panama City, it explains why overdoses have become harder to predict and harder to treat.
A Quick Chemical Fingerprint of the Street Supply
Researchers at the National Institute of Standards and Technology, or NIST, published the study in “Drug Testing & Analysis” on October 7. They analyzed 4,563 drug-residue samples collected across the country from January 2024 through June 2026. A technique called DART-MS lets them identify the trace compounds in a sample in seconds. Older methods took tens of minutes.
The headline finding is about volume. In early 2024, a typical sample held one or two added substances. Samples with six or more are now more common.
Medetomidine Is Replacing Xylazine
Two of the added substances are veterinary sedatives. Xylazine is the one some people may have heard of. We even wrote articles about it on this blog in 2024 and 2025. The NIST team found it much more common in East Coast samples than in the West, and a more potent sedative called medetomidine is replacing it. East Coast samples were much more likely to contain medetomidine than West Coast samples from 2024 through 2026.
The study doesn’t name Florida or break out samples by state, so we can’t say what share came from the Southeast. The CDC’s regional data fills in some of the gap. In its surveillance of opioid-positive samples from July through December 2025, medetomidine turned up in 74.2 percent of samples in the Northeast, 56.2 percent in the Midwest, 30.1 percent in the South, and 3.8 percent in the West. Sentinel sites in Broward and Palm Beach counties were part of the Southern count. The NIST team has tracked additives moving from Philadelphia to Delaware and Maryland and then west, and the CDC’s regional numbers are consistent with that kind of spread.
The Panhandle is not Broward County, and a regional average can’t tell you what is in a pill sold in Bay County. It does suggest that medetomidine is no longer someone else’s problem, it is our problem here, in all likelihood.
Other Things in the Mix
The study also tracked BTMPS, an industrial chemical used in plastics manufacturing. It has appeared in both East and West Coast samples since summer 2024 and can cause eye inflammation and burning. Samples from the West tend to have fewer additives, but at higher concentrations.
The researchers found that these additives rise and fall in cycles, each on its own schedule. One of the study’s authors, Edward Sisco, put the clinical problem this way: “With more additives, it’s both more difficult to analyze a sample and more difficult to treat a drug overdose.”
Sedation That Doesn’t Lift After Naloxone
Naloxone reverses opioids, and medetomidine is not an opioid. The CDC says prolonged sedation that continues after naloxone is a sign clinicians should consider medetomidine involvement.
The CDC’s guidance for a suspected overdose has not changed: give naloxone and call 911. If the person is still deeply sedated afterward, tell the paramedics what happened and how many doses you gave. That information helps them look beyond opioids.
Withdrawal Can Be the Dangerous Part
Medetomidine also changes what happens when someone stops using. According to the CDC, regular exposure followed by stopping can cause severe withdrawal that starts quickly, can damage organs, and often needs emergency or intensive care. Signs include a racing heart, severe high blood pressure, shaking, chest pain, and nonstop vomiting.
That is a reason not to go it alone. A person who has been using street fentanyl and wants to quit may be facing a more complicated withdrawal than they expect, and a medically supervised detox can monitor for it.
The Supply Will Keep Moving
Today’s list of additives will not be next year’s list. NIST is already studying a newer class of opioids it calls “orphines,” some more potent than fentanyl. What stays constant is that nobody using street drugs can know what they are taking.
If you or someone you love is using, the safest choices are the same ones we’ve always recommended: don’t use alone, keep naloxone in the house, and call 911 fast. And if the next step is treatment, our residential program for drug and alcohol rehab is in Panama City. You can call without a plan.
