WASHINGTON (Reuters) - Trump administration officials are divided over part of a proposal to crack down on illicit versions of fentanyl, the deadly synthetic painkiller that U.S. President Donald Trump targeted in declaring a national opioid abuse emergency.

FILE PHOTO: Plastic bags of Fentanyl are displayed on a table at the U.S. Customs and Border Protection area at the International Mail Facility at O'Hare International Airport in Chicago, Illinois, U.S. November 29, 2017. REUTERS/Joshua Lott

In an inter-agency dispute that highlights the challenges of curbing opioid abuse, the U.S. Drug Enforcement Administration (DEA) is publicly backing tighter rules for fentanyl analogues, which are slightly altered copycat versions of the powerful drug fueling an explosion in overdoses.

But an office of the U.S. Department of Health and Human Services (HHS) is raising concerns outside of public hearings, sources told Reuters, about the DEA-backed legislation, offered by Senator Ron Johnson and Representative Jim Sensenbrenner, both Republicans.

Normally, the DEA and the U.S. Food and Drug Administration review chemical compounds individually to assign each one a controlled substance classification, with the FDA determining if such “scheduling” decisions are scientifically valid.

In this case, the bill would cut the FDA out of the time-consuming review process by letting the DEA permanently classify illicit fentanyl analogues as Schedule I drugs, like heroin, which are deemed to be addictive with no medical use.

The DEA says these legal changes would help prosecutors keep pace with criminals who constantly churn out chemically tweaked fentanyl analogues to evade strict Schedule I regulations.

But an expert from HHS’s National Institute on Drug Abuse (NIDA) quietly warned Senate staff at a private June 20 briefing that permanently placing all fentanyl analogues into Schedule I poses problems, according to an attendee who spoke to Reuters anonymously because the briefing was private.

The draft bill would not only put all fentanyl analogues into Schedule I before anything is known about their potential medical benefits, but would also make it harder for researchers to win approval to study the analogues to potentially develop new approaches to tackling the surge in overdoses, the NIDA expert said.

An HHS spokesperson told Reuters that the department has no position on the DEA-backed bill, but confirmed that HHS does have some concerns.

“These compounds can be used to develop and test new medications for preventing opioid addiction and overdose,” the spokesperson said, noting that putting fentanyl analogues into Schedule I without accommodating scientists with a streamlined approval process “could slow valuable research aimed at addressing the opioid crisis.”

Of 70,200 U.S. drug overdose deaths in 2017, according to the CDC, about 41% involved synthetic opioids, such as fentanyl and illicit analogues of it. Most of them are made in China.

Fentanyl, some versions of which are approved to treat cancer pain, is 100 times more potent than morphine.

APPROACHING DEADLINE

While the debate over fentanyl analogues dates back to the Obama administration, the rising death toll has made the issue more urgent.

Adding to that urgency is a February 2020 deadline, when a temporary 2018 DEA emergency order that placed all fentanyl analogues into Schedule I will expire.

During a July 1 press briefing, DEA Assistant Administrator John Martin downplayed the bill’s impact on research, but acknowledged HHS’s concerns.

“They have some concerns,” he said, adding that DEA is “trying to eliminate the perception out there in the research community that it’s going to be a hindrance.”

Because Schedule I drugs have high risk of abuse, the DEA imposes strict regulations for research applicants. It requires the drugs to be stored in a safe bolted to the floor and each compound must have a separate DEA registration.

“Trying to do research on Schedule I compounds is really difficult for scientists. There are all kinds of regulatory hurdles,” said Sandra Comer, public policy officer for the College on Problems of Drug Dependence, a scientific group.

Exactly how many fentanyl analogues would be impacted by the bill is unknown.

While Martin told reporters in the July 1 briefing it could involve “hundreds to maybe a thousand” fentanyl analogues, another government official who participated in the June 20 private briefing told Senate and other government staffers it could affect “millions” to “an infinite” number, according to people familiar with the matter.

A DEA spokeswoman said the agency disagreed with that estimate and that Martin’s estimate was accurate.

Meanwhile, an official with the Office of National Drug Control Policy told lawmakers in public testimony on June 4 it could potentially impact more than 3,000 fentanyl analogues.

The DEA did not have any immediate comment on that estimate.

Some groups are urging lawmakers to oppose the bill, saying it would chill research and give the DEA too much power.

“This administration has tried to take a criminal justice approach to the overdose crisis,” Drug Policy Alliance national affairs director Michael Collins said, “when it is very clear it is a public health crisis.”