Amid an outbreak of dangerous infections by pain drug abusers,the U.S. Food and Drug Administration has asked Endo InternationalPlc to stop sales of its powerful opioid painkiller Opana ER, thefirst time the agency has taken such a step.

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While the drug was approved by the FDA for legitimate painrelief, it’s become a favorite of addicts. After Endo reformulatedthe drug to try and reduce its potential for abuse, many drug userswent from crushing and snorting the pill to injecting it. That ledto “a serious outbreak of HIV and hepatitis C,” the FDA said in astatement.

The move marks a shift in FDA policy, pushed by CommissionerScott Gottlieb, to consider how opioids are used not just byappropriate patients but also by drug abusers. Thousands ofAmericans die each year from opioid overdoses, as do many more whoswitch from the pills to heroin.

The agency believes it has the legal authority to look beyondpatients to whom the drug is prescribed and to include abusers inthe risk-benefit calculation it considers when reviewing a drug,Gottlieb said.

“We’re going to be focusing policy attention on looking atrisk-benefit not only in the labeled indication but also in thesetting of the abuse of narcotics both in the pre- and post-marketconsideration,” Gottlieb said in a phone interview.

Gottlieb declined to say if there were other opioids that theagency was reviewing for similar risks. The FDA doesn’t typicallyorder drugs off the market, but asks their makers to pull them --which they usually do.

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Endo’s shares plunged as much as 13 percent to $12.04 on Friday,the biggest intraday decline in seven months, and traded at $12.15as of 9:51 a.m. New York time.

The drugmaker said it is reviewing the request and “evaluatingthe full range of potential options as we determine the appropriatepath forward.”

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“Endo remains confident in the body of evidence establishedthrough clinical research demonstrating that Opana ER has afavorable risk-benefit profile when used as intended in appropriatepatients” the company said in a statement. Sales of the drugtotaled $158.9 million last year, about 4 percent of the company’srevenue.

In April, as he was being vetted for the commissioner spot,Gottlieb said that the opioid crisis would be the agency’s toppriority. Last month, he set up a steering committee at the FDA toexplore policies to reduce opioid use and reconsider whether theagency was doing enough to take into account the risk of abuse whenevaluating opioids. The committee had its second meeting Thursday,unrelated to Opana ER, he said.

“We are facing an opioid epidemic -- a public health crisis, andwe must take all necessary steps to reduce the scope of opioidmisuse and abuse,” Gottlieb said in the statement announcing therequest to pull the drug.

HIV outbreak

An HIV outbreak took place in Indiana in 2015, linked to the useof dirty needles by pain-pill abusers who injected the drugs.

“The abuse and manipulation of reformulated Opana ER byinjection has resulted in a serious disease outbreak,” saidJanet Woodcock, director of the FDA’s Center for Drug Evaluationand Research. “When we determined that the product had dangerousunintended consequences, we made a decision to request itswithdrawal from the market.”

The FDA has been reviewing the drug’s risks for several months.In March, an FDA advisory panel voted 18-8 that the benefits ofOpana ER no longer outweighed its risks, because of the potentialfor abuse and misuse.

“For those on the street it is interchangeable with heroin,” onepanel member, University of California, San Francisco, professorDaniel Ciccarone said during the March hearing.

The FDA says it has approved 10 opioid medications asabuse-deterrent, including Pfizer Inc.’s Troxyca and Purdue PharmaLP’s OxyContin.

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