In Pawtucket, R.I., near a storefront advertising “free” cell phones, J.R. sat in an empty back stairwell and showed a reporter how he tries to avoid overdosing when he smokes crack cocaine.

(NPR is identifying him by his initials because he fears being arrested for using illegal drugs.)

It had been several hours since his last hit, and the chatty, middle-aged man’s hands moved quickly. In one hand, he held a glass pipe. In the other, a lentil-sized crumb of cocaine.

Or at least J.R. hoped it was cocaine, pure cocaine — uncontaminated by any , a potent opioid that was linked to nearly 80% of all overdose deaths in Rhode Island in 2022.

He flicked his lighter to “test” his supply. If it has a “cigar like sweet smell,’’ he said, it means that his cocaine is laced with “fetty” or fentanyl. He put the pipe to his lips and took a tentative puff. “No sweet,” he said, reassured.

, an addiction specialist and researcher who teaches at Brown University. “People are gonna die today because they buy some cocaine that they don’t know has fentanyl in it.’’

The mix of stimulants like cocaine and methamphetamines with fentanyl – a synthetic opioid 50 times than heroin – is driving what experts call the opioid epidemic’s “.” The mixture presents powerful challenges to efforts to reduce overdoses, because many users of stimulants don’t know they are at risk of ingesting opioids and so don’t take overdose precautions.

The only way to know if cocaine or other stimulants contain fentanyl is to use drug-checking tools such as fentanyl test strips – a best practice for now embraced by for combating drug overdose deaths. Fentanyl test strips cost as little as $2 for a two-pack online, but many front-line organizations also give them out for free.

In the U.S., the first wave of the long-running and devastating opioid epidemic began with the abuse of prescription painkillers (early 2000s); the second wave involved an increase in heroin use, starting around 2010.

published in 2023 in the scientific journal Addiction. 

The stimulant in the fatal mixture tends to be cocaine in the Northeast, and methamphetamine in the West and much of the Midwest and South.

“The number one thing that people in the U.S. are dying from in terms of drug overdoses is the combination of fentanyl and a stimulant,’’ said , a researcher at UCLA and the study’s lead author.

“Black and African Americans are disproportionately affected by this crisis to a large magnitude, especially in the Northeast.’’

Factors driving polydrug overdoses

It’s not clear how much of the latest trend in polydrug use is accidental or intentional. A recent study from found that most people who use fentanyl do so at times intentionally and other times unintentionally.

People often use stimulants to power through the rapid withdrawal from fentanyl, Friedman said. And the high-risk practice of using cocaine or meth with heroin, known as , has been around for decades.

Other factors include manufacturers adding the cheap synthetic opioid to a stimulant to stretch out their supply, or dealers mixing up bags.

But in Rhode Island, researchers said, many people still think they are using unadulterated cocaine or crack — a misconception that can be deadly.

Stimulant users unprepared for fentanyl’s ubiquity

“Folks who are using stimulants, and not intentionally using opioids, are unprepared to respond to an opioid overdose…because they don’t perceive themselves to be at risk,’’ said , a Brown University epidemiologist and a principal investigator in a new, called Preventing Overdoses Involving Stimulants.

of overdose deaths involving cocaine in 2022, after D.C., Delaware and Vermont. according to the U.S. Centers for Disease Control and Prevention (CDC).

People who don’t regularly use opioids have lower tolerance, which puts them at higher risk of an overdose.

And many of the people interviewed in the study also use drugs alone, so if they do overdose they may not be found until it’s too late.

Dubois was a single mother raising two Black sons. The older son, Clifton, had been struggling with addiction since he was 14, she said. Clifton also had been diagnosed with ADHD and a mood disorder.

Back in March 2020, Clifton had just checked into a rehab program as the pandemic ramped up, Dubois said.

Because of the lockdown at rehab, Clifton was upset about not being able to visit with his mother. “He said, ‘if I can’t see my mom, I can’t do treatment,’” Dubois recalled. “And I begged him” to stay in treatment.”

But soon after, Clifton left the rehab program. He showed up at her door. “And I just cried,” she said.

Dubois’s younger son was living at home. Dubois didn’t want Clifton doing drugs around his younger brother. So she gave Clifton an ultimatum: “If you want to stay home, you have to stay drug free.”

Clifton went to stay with family friends, first in Atlanta, and later in Woonsocket, an old mill city that has Rhode Island’s of drug overdose deaths.

recently published in The American Journal of Psychiatry.

But it’s too simplistic to merely focus on whether fentanyl is present, or not, said Joseph Friedman, the researcher at UC San Diego and the study’s author.

For years, hospitals have safely used medical grade fentanyl for surgical pain because the potency is strictly regulated.

“It’s not the strength of fentanyl, that’s risky,’’ he said. “It’s the fact that the potency fluctuates wildly in the illicit market.”

Studies of street drugs, he said, show that in illicit drugs the potency can vary from 1% to 70% fentanyl.

“Imagine ordering a mixed drink in a bar and it contains one to 70 shots,’’ Friedman said, “and the only way you know is to start drinking it…There would be a huge number of alcohol overdose deaths.’’

Drug checking technology can provide a rough estimate of fentanyl concentration, he said, but to get a precise measure requires sending drugs out to a laboratory.

offer a low-cost way to prevent overdoses by detecting the presence of fentanyl, regardless of potency, in cocaine and other illicit drugs.

In Rhode Island, the test kits are available for free from harm reduction groups such as .

But the test strips only work if people use them – and then don’t consume the drugs if they test positive for fentanyl. And not enough people who use stimulants do.

This story comes from NPR’s health reporting partnership with and .