A nurse at Immanuel St. Joseph's Hospital in Mankato has been fired for allegedly replacing the powerful narcotic fentanyl with sterile saltwater in vials used for patients undergoing medical procedures.

The nurse later used the drug, said Dr. Greg Kutcher, hospital president, which is part of the Mayo Health System. He would not identify the nurse, but the nurse has been fired and reported to the Drug Enforcement Administration and the Minnesota Board of Nursing for potential criminal and professional disciplinary investigations.

Letters were sent to 335 patients telling them that they may have been given a saline solution instead of the powerful pain medication fentanyl. Kutcher said the narcotic had been removed from supposedly tamper-proof single dose vials and replaced with saline.

Fentanyl, an opium-based pain medication, is almost always used only in hospitals because it is powerful and fast-acting. It's considered 80 times stronger than morphine and highly addictive.

After consulting with the Minnesota Department of Health, hospital officials concluded that none of the patients are at risk for infection or harm from not receiving sufficient pain medication during their procedures, Kutcher said.

The tampering was discovered Feb. 25 when employees found empty fentanyl vials in a wastebasket. Within eight days, hospital officials identified the nurse who had used them and also found that the nurse had secretly removed the drug from many other vials, which were put back into the hospital's supplies.

The vials come with a plastic top over an aluminum foil cover, with a rubber stopper under that. The nurse was able to remove the plastic and foil tops, draw out the drug with a syringe and replace it with saline. The nurse then carefully replaced the tops so the vials appeared untouched, Kutcher said.

"Unless you were looking for it, you wouldn't see it," he said. "We're glad we caught it and it didn't go on longer."

Patients likeliest to be affected were those who would have needed the medication while undergoing cardiac catheterization and endoscopic or radiological procedures two weeks before March 4. To be certain they didn't miss any patients, hospital officials also sent letters to anyone who had those procedures between Feb. 1 and March 4, Kutcher said.

Kutcher said that the internal investigation, along with consultation with the Minnesota Department of Health, has reassured officials that the patients are not at risk for infection. They probably received the proper amount of painkiller during their procedure even if they got saline instead of fentanyl, Kutcher said. If a patient was not sufficiently sedated, they would be given more of the drug as needed, Kutcher said.

"There is no evidence there was inadequate sedation," he said.

The hospital has notified the manufacturer of the drug about how the tampering occurred.

Josephine Marcotty • 612-673-7394