After a series of high-profile failures in the early 2010s, the compounding pharmacy industry took its share of body blows from an FDA looking to impose its will.

Now, after years of lockdown, the FDA is turning to its old nemesis to help ease the burden COVID-19 has placed on hard-hit hospitals. 

The FDA will temporarily allow hospitals to source hard-to-find drugs from compounding pharmacies to treat certain patients hospitalized with severe COVID-19, the agency said Monday.

The regulation, meant to last as long as hospitals continue to encounter shortages of key drugs, applies to compounding pharmacies that aren't already sanctioned by the FDA as "outsourcing facilities." To qualify, the copycat drugs must be listed on the FDA's shortages list, and hospitals must have exhausted all other options to access a commercial version of the drug. 

The FDA emphasized that its extraordinary step was designed to be temporary as the pharmaceutical supply chain faces "unprecedented disruptions" amid the novel coronavirus pandemic to provide drugs used for patients placed on respirators. 

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"(The) FDA generally tries to address potential and actual drug shortages by working through the global pharmaceutical supply chain, rather than relying on compounded drugs, and focuses on restoring supplies of FDA-approved drugs," the FDA said in a release.

"However, in light of unprecedented disruptions," the agency added, "additional flexibility is temporarily needed to help ensure that treatment options are available when hospitals are unable to obtain FDA-approved drugs used for hospitalized patients with COVID-19."

The immense strain the novel coronavirus has put on the global supply chain has made strange bedfellows of the FDA and compounding pharmacies, long pitted against one another in regulatory battles. 

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In 2016, the FDA capped a multiyear crusade against compounding pharmacies, which produce their own copycats of commercial medicines, with draft guidance that defined the requirement for "patient need" for copies. 

Under the guidelines, individual compounders were allowed to make versions of brand-name drugs during shortages or after a medicine has been discontinued. A compounding pharmacy could also custom-produce a drug if a particular patient needed a formulation change, such as different dosage strengths.

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What specifically wasn't allowed: Compounding an FDA-approved drug simply to provide it at a lower cost.

The FDA rules followed a closely followed investigation in 2012, when the New England Compounding Center was charged with manufacturing a steroid that triggered a deadly fungal meningitis outbreak.

In June 2017, the center's chief pharmacist, Barry J. Cadden, was convicted of more than 50 counts of mail fraud for his role in the outbreak. While a majority of Boston jurors voted to convict Cadden of 23 of the 25 murder charges filed against him, a unanimous decision couldn’t be reached at the time.

RELATED: Coronavirus demand causes shortages of key hospital anesthetics, painkillers

Despite the long history, a run on key drugs used for hospitalized COVID-19 patients has opened the FDA to loosening restrictions. 

Earlier this month, the FDA posted updated shortages of anesthetics propofol and midazolam, citing increased demand. The U.S. Drug Enforcement Agency (DEA) said at the time it would allow increased production and imports of midazolam, a controlled substance, to combat ongoing shortages. The DEA included a range of painkillers and sedatives on its production increase list, including fentanyl, ketamine, phenobarbital and diazepam. 

In the case of fentanyl, used to treat ventilated patients, hospitals require large 50-milligram doses of the opioid that quickly ran scarce, causing a cascade effect down the supply chain, according to the Washington Post.