The stockpiles began to run low soon after the outbreak hit New Jersey.

As the cases mounted, Holy Name Medical Center faced a spike in demand for the medications needed to treat COVID-19 patients. The Teaneck hospital’s pharmaceutical buyer made a frenzy of calls trying to track down the drugs, but they are getting harder to find.

Holy Name has managed as the coronavirus pandemic continues to sweep across the state. But forecasting how long its supplies will last is difficult when the predicted peak in cases remains a week or two away, according to health experts.

“A seven-day supply, you think, would be a relative comfort level,” said Nancy Palamara, director of the Pharmacy and Infusion Center at Holy Name. “You just don’t know what’s coming.”

Holy Name is among the many New Jersey hospitals struggling with a limited supply of drugs used to sedate patients or keep their airways open, as well as antivirals, antibiotics and antimalarials.

Over the past month, the coronavirus pandemic has revealed a vulnerability in the drug supply chain: Many of the medications used in the U.S., or their critical ingredients, come from China and other nations hampered by the outbreak.

As hospitals on the front lines grapple with a potential shortage of ventilators and personal protective equipment, they are staring down the barrel of yet another challenge: a shortage of drugs to treat COVID-19 patients.

Pharmaceutical companies have stockpiles of medication and contingency plans in place to address supply issues. But the unknown longevity of the outbreak in New Jersey and strict rules in the pharmaceutical industry leave the future of some medical supplies uncertain.

“Regardless of whatever contingency a company puts into place, there’s still a limited amount,” said William McLaury, a supply chain management professor at Rutgers University, who previously served as the executive director of pharma supply chain for Novartis Pharmaceuticals. “If this were to go on for three months, six months, nine months, [backups] will run out. It’s a limited supply. There might be enough, but to say there’s never going to be a problem is probably unrealistic.”

Premier Inc., a health care improvement company that provides analytics and consulting services to hospitals, found last week that the supply of 15 drugs needed to provide care for COVID-19 patients had begun to dwindle. The drugs can be used to aid patients on ventilators and reduce fever, pain and infections.

The list also includes hydroxychloroquine, an antimalarial drug touted by President Donald Trump as a possible coronavirus treatment. The drug’s potential led to increased demand, with the U.S. purchasing 29 million pills. However, many medical experts have said it’s too soon to know if the drug is a safe and effective treatment for COVID-19 patients.

Judith Perschilli, commissioner of the state’s Department of Health, acknowledged the drug shortage in a media briefing last week.

“We have asked the [hospital] CEOs to let us know particularly about medication supplies, because there are some shortages of medications," she said. “And we did get from one hospital up in the north that some medications that are used to sedate patients, their volume that they have on the shelves is going low. So, we’re looking into that.

"But I’ve only heard from one right now. But it’s exactly the types of medications that you would use particularly for someone on a ventilator — fentanyl, Versed, things like that.”

Kerry McKean Kelly, a spokeswoman for the New Jersey Hospital Association, said the group has heard from multiple hospitals about a tightening of drug supplies, and has met weekly with pharmacists to discuss ways to secure them.

She said the shortages include hydroxychloroquine, at least one antibiotic, and propofol and norepinephrine, both of which are used for patients on ventilators.

“We can’t overlook the critical role of pharmacists in the COVID-19 response,” McKean Kelly said. “They are part of the hospital team facing the same challenges of providing treatment to a surge of patients, many of them critically ill.”

The U.S. Food and Drug Administration began tracking possible drug shortages due to disruptions in February. But it noted the complexities of the drug supply chain made it impossible for officials to know the total amount of materials and drugs that come from China.

Manufacturers in other industries have pivoted, with textile producers stitching up masks and gowns for hospital workers or distilleries making hand sanitizer. Some 3D printers have taken a stab at ventilators and face shields. But regulations in the drug manufacturing industry don’t allow such an easy shift, and it often takes years before producers can add to their capacity or receive new approvals from the FDA.

McLaury said the pause in China’s manufacturing sector, which makes many of the antibiotics used in the U.S., could take a month or two to overcome. That delay comes despite many Chinese factories resuming production in March as the worst of the country’s outbreak subsided.

Still, he cautioned against hysteria surrounding the drug market, thanks to contingencies in the supply chain.

“I don’t see a reason to panic right now,” he said. “That’s not to say that there’s no concern. Every company, every country out there is facing a reduced workforce. It’s not business as usual.”

There are other obstacles as well.

Many of the drugs have purchasing limits based on historical usage, Holy Name’s Palamara said. But the hospital has requested overrides, listing the number of coronavirus patients under their care to try to get more.

Complicating the situation further, medical professionals have trouble forecasting how long medication supplies will last, as each patient needs a different dose, Palamara said.

There are substitutes for some drugs it can use while awaiting the next shipment, she said. Unlike with masks and ventilators, the government has not waded into the allocation of pharmaceuticals.

Hospitals around the state have reached out to one another, and are likely to help if they can during the outbreak. But it’s only a matter of time until they are facing the same problems.

Still, Palamara said she doesn’t expect Holy Name to face shortages so steep they would have to turn patients away.

But she did emphasize the vital need for the drugs, which have moved to the back burner in public conversations about critical supplies.

“You can have all the ventilators in the world, but if you don’t have the drug to keep people alive on the ventilator, the ventilator is not going to be able to help,” Palamara said.

Amanda Hoover can be reached at ahoover@njadvancemedia.com. Follow her on Twitter @amandahoovernj. Find NJ.com on Facebook.

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