The Rite Aid pharmacy chain "knowingly" contributed to the nation's opioid crisis, the U.S. Justice Department alleged in a lawsuit filed on Monday.

"We allege that Rite Aid filled hundreds of thousands of prescriptions that did not meet legal requirements," Associate Attorney General Vanita Gupta said. "According to our complaint, Rite Aid's pharmacists repeatedly filled prescriptions for controlled substances with obvious red flags, and Rite Aid intentionally deleted internal notes about suspicious prescribers. These practices opened the floodgates for millions of opioid pills and other controlled substances to flow illegally out of Rite Aid's stores."

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The lawsuit, filed in Cleveland federal court, said Rite Aid repeatedly filled prescriptions from May 2014 to June 2019 that were medically unnecessary, for off-label use or not issued in the usual course of professional practice. Rite Aid pharmacists were accused of ignoring obvious signs of misuse, including in prescriptions for "trinities," a combination of opioids, benzodiazepine and muscle relaxants preferred by drug abusers for their increased euphoric effect.