The fentanyl in her blood was between 15 and 20 times the appropriate level, according to a toxicology report.

The F.D.A. documents obtained by researchers included a survey by the industry group in 2013 in which nearly 40 percent of T.I.R.F. prescribers said they had used the drug to treat chronic pain in patients who did not have cancer, like Ms. Fuller.

In the survey, 42 percent of pharmacists stated that the drugs were appropriate for those ailments.

In another survey three years later, in February 2017, almost one in five T.I.R.F. prescribers (18 percent) and almost one in two patients (48 percent) said they believed, wrongly, that the medications were formally approved by the F.D.A. to treat illnesses other than cancer.

Just over half of patients prescribed the drugs were not already taking a round-the-clock opioid regimen, and therefore were susceptible to an accidental overdose, according to an analysis of commercial health plan claims for more than 25,000 patients by the industry group in 2016. A follow-up analysis had a similar result.

In fact, in an effort to address “concern regarding patient access,” the industry group in 2013 had taken steps to make it easier to prescribe to patients without opioid tolerance.The group removed protective language from a mandatory patient-prescriber agreement form attesting that the “patient is opioid tolerant,” and instead required a prescriber only to indicate that “I understand” the meaning of opioid tolerance.

The form was also altered to omit a clause that had required patients to affirm that they were already using a round-the-clock opioid regimen.

“It is not open for debate that the risk of these drugs among patients who lack tolerance is unacceptably high. It’s quite clear-cut,” said Dr. Caleb Alexander, a physician who co-directs the Center for Drug Safety and Effectiveness at Johns Hopkins and led the research on the documents.