Hospitals in regions experiencing a surge of coronavirus patients are struggling to maintain supplies of antibiotics, antivirals, sedatives required for patients on ventilators and other drugs produced in countries where the coronavirus has shuttered or curbed manufacturing.

Although overlooked by a public focused on shortages of ventilators and personal protective equipment, hospitals are increasingly concerned about future shortages of lifesaving drugs as authorities in India and other countries producing the drugs try to guarantee supplies for their own people.

New York, the state with the highest number of infected and dying in the country, has experienced spikes in demands for fentanyl and other sedatives needed for patients experiencing respiratory failure who are placed on ventilators for up to two weeks. The Food and Drug Administration placed another sedative called midazolam on an official drug shortage list last month.

“Everyone has been discussing the requirements for more vents, but no one is discussing the needs for patients when they are on the vents, the sedatives, anesthetics and paralytic agents,” said Onisis Stefas, vice president and chief pharmacy officer at Northwell Health, a 23-hospital system in New York, which has experienced the highest spikes in coronavirus patients in the United States.

Other drug shortages have emerged as unintended consequences of the coronavirus. When doctors avoided nebulizers for patients with respiratory trouble hoping to prevent the coronavirus from getting airborne inside their facilities, they inadvertently created shortages of everyday albuterol asthma inhalers in hospitals and retail pharmacies.

The shortages highlight heavy U.S. dependence on bulk drug ingredients and finished medicines manufactured in China, India and Europe, medical experts say, but also the FDA’s limited ability to monitor global supply chains, creating vulnerabilities for the health system in a time of crisis.

If supply conditions worsen, particularly in regions like New York suffering from rapid surges in patients, a lack of sedative and paralytic drugs needed to safely intubate patients with severe respiratory failure could prove just as critical as a lack of ventilators, said specialists.

“The pharmacy supply chain is really not built for this,” Stefas said. “They make their product and release it based on historical data. It makes situations like this, that are not expected, very difficult to manage.”

Hospitals require large, 50-milliliter vials of fentanyl to treat ventilated patients humanely, but suppliers quickly ran out and had only 2-ml vials in warehouses – which do not provide enough of the drug to administer efficiently to patients, Stefas said. Northwell worked with the FDA and the Drug Enforcement Administration to win permission for manufacturers to fill more 50-milliliter vials, he said.

The DEA announced Tuesday it was broadly boosting production quotas for a handful of key sedative drugs used for ventilator patients, including fentanyl and midazolam. Fentanyl was widely abused in America’s opioid addiction epidemic, and DEA last September proposed reducing quotas of the drugs. The agency made clear the increase is temporary during the covid-19 crisis.

“After the health emergency recedes, DEA will re-evaluate demand and adjust (quota) levels as needed,” the agency said.

GlaxoSmithKline, the maker of Ventolin inhalers, said it has ramped up production to 24 hours, seven days a week at plants in France and North Carolina. It said it chartered jets to fly in emergency supplies from its French facilities instead of using shipping containers.

“GSK is experiencing an unprecedented level of demand for Ventolin inhalers in the U.S.,” said company spokesman Evan Berland. “We are doing everything possible to get as much Ventolin to people as we can.”

Drugstores also are seeking emergency permission from states to allow pharmacists to swap in equivalent therapies to albuterol inhalers without having to call a physician to get another prescription.

“The physician doesn’t want to be bothered when he’s trying to save a covid-19 patient,” said Kathleen Jaeger, senior vice president of pharmacy care and patient advocacy at the National Association of Chain Drug Stores.

Last month featured an explosion of purchasing of chloroquine and hydroxychloroquine by hospitals, doctors and consumers responding to President Donald Trump’s exhortations that the decades-old anti-malarials can treat covid-19, a White House claim that remains unproven by rigorous clinical trials. The runs and hoarding of the drugs nearly wiped out U.S. supply in a matter of weeks.

Drug manufacturers and the FDA do not disclose publicly the sources of raw ingredients and packaged medicines sold in the United States, and critics say the FDA lacks the power to track where drugs are coming from. Congress last month gave the FDA new powers to peer more deeply into where drugs and ingredients are manufactured, but the authority does not take effect until September. The agency said it is working with drug manufacturers to respond to shortages caused by the pandemic.

“This communication and the full cooperation of companies providing specific and necessary information is imperative in order for us to have an accurate understanding of the supply landscape and work to take proactive steps to mitigate shortages,” the agency said in a statement Thursday. “This is an evolving, dynamic situation and the FDA is actively engaged.”

Generic drugs account for about 90 percent of all prescriptions filled in the United States. About 87 percent of the factories making raw pharmaceutical ingredients used in generics are located overseas, with 48 percent in India and China, according to industry estimates. China shut down drug manufacturing facilities during its coronavirus lockdown, but some of those facilities are expected to come back on line in coming weeks and months.

The shortages show how a lack of basic information is hurting U.S. planning and readiness for a variety of disasters, said Stephen Schondelmeyer, a professor of pharmaceutical economics in the College of Pharmacy at the University of Minnesota.

“What we are living through now are some of the worst-case-scenarios of what could occur,” he said. “We should be concerned about the safety and resilience of our drug supply in terms of market concentration, foreign dependence and a lack of transparency of where these drugs are coming from.”

A New Zealand government website Schondelmeyer and other Minnesota researchers have been using gives insights into the origins of the global supply. New Zealand is the only country in the world with such a public resource, he said.

Although the comparisons to the United States are inexact, the New Zealand data show some of the crucial pharmaceutical products falling into shortages in the United States are made in India, Italy and other countries that have been hit hard by coronavirus and are locking down their populations or blocking pharmaceutical exports. The University of Minnesota project to analyze the supply chain has identified 156 drugs that could go into shortage in the next 90 days, although the list is still preliminary and has not been publicly released.

Schondelmeyer faulted drug manufacturers for a lack of transparency about looming shortages.

“They say our drugs and supply are secure and we don’t have any problems,” he said, “and suddenly we have shortages in the system.”

Asked to respond, the Association for Accessible Medicines, which represents generic drug manufacturers, said it supports new FDA rules that will give the agency greater ability to monitor foreign and domestic supplies. Those numbers do not account for the volumes of ingredients that come from those factories.

Shortages related to the coronavirus have been caused by the sudden jump in demand for medicines, followed by a lag of only a few days for industry to fill the gaps, said Erik Komendant, vice president of federal affairs at the Association for Accessible Medicines.

“It’s our goal to continue to work with the agency to make sure they have the information they need, and that we have the right sort of structures in place to ensure the global nature of the supply chain can continue to meet the needs of patients,” he said. Komendant added he expected the Trump administration and Congress will consider ways to bring more drug manufacturing to the United States as part of the next round of federal economic stimulus.

“A potential element is what are the incentives in place, what can we do as a country, so that we attract more investment, more manufacturing, here at home,” Komendant said. “If there is increased demand to respond to any number of crises, we’ve got to make sure that U.S. manufacturing is a part of the solution.”

The White House is citing shortages as it pushes to bring more drug manufacturing to the United States. White House trade adviser Peter Navarro, an advocate of protectionist trade policies, said in an interview that one option would be to make rules requiring federal agencies and Medicare and Medicaid to “buy American” for essential drugs, from antibiotics to anesthesia. The government also could offer tax incentives and government loans.

Before the coronavirus struck, members of Congress already were worried about chronic shortages of medications such as antibiotics, seeing a potential security threat in the FDA’s limited information about the drug supply chain.

Sen. Susan Collins, R-Maine, was among lawmakers last year who proposed requiring drug manufacturers to disclose to the FDA each year where their drugs are made, including their raw materials, called “active pharmaceutical ingredients.”

A weaker version of the Collins proposal was included in the $2 trillion stimulus package Congress passed last month. It requires manufacturers to disclose sources of raw materials when there are shortages and maintain contingency plans available for government inspection.

Premier Inc., a major group purchasing organization for hospitals, is urging the FDA to use its new powers quickly to investigate and anticipate drug shortages, said the company’s senior director of advocacy, Soumi Saha.

She cited two examples of the FDA’s blind spots. Hurricane Maria crippled manufacturing in Puerto Rico in 2017, creating a dire shortage of saline solution in the United States. The FDA had been caught unaware that a high degree of manufacturing concentration had left the nation vulnerable to disruption of a basic medical supply, Saha said. In July 2018, small amounts of cancer-causing agents were discovered in common generic high blood pressure medications manufactured in China and India, leading to widespread recalls. The contaminants turned up in pills distributed by multiple manufacturers through November 2019.

“It took months for the FDA to identify what other finished-dose products used the same API,” Saha said.

India, which exported nearly $6 billion of pharmaceuticals to the United States in the year ending March 2019, has emerged as crucial choke point for supplies of hydroxychloroquine, the anti-malarial drug Trump is boosting to treat coronavirus. Severe shortages have prevented some patients who rely on the drugs for approved uses, such as lupus and rheumatoid arthritis, from getting their routine supplies.

Nearly half the U.S. supply of hydroxychloroquine comes from India, according to an analysis by Bloomberg Intelligence.

Faced with a sharp increase in its own coronavirus cases, India has swung between the impulse to stockpile drugs at home and the need to meet obligations abroad. In recent weeks, it restricted the export of about a dozen drugs, including paracetamol, several antibiotics and an anti-viral medication. It banned the export of hydroxychloroquine “without any exception.”

Trump spoke with Indian Prime Minister Narendra Modi on the phone on April 5 and told reporters he urged Modi to allow shipments of hydroxychloroquine to the United States. “If (Modi) doesn’t allow it to come out, that would be OK, but of course, there may be retaliation,” Trump said, a statement widely viewed in India as a threat.

New Delhi then reversed course, saying it would allow exports of hydroxychloroquine to nations “particularly badly affected by the pandemic” as well as to neighboring countries. It also removed the restrictions imposed on the dozen earlier drugs, with the exception of paracetamol. Together with hydroxychloroquine, the demand for the anti-fever drug will be “continuously monitored,” a spokesman for India’s foreign ministry said Tuesday.

Indian drugmakers also are racing to increase production of hydroxychloroquine for use in India and beyond. Zydus Cadila, a major manufacturer of the drug, ramped up its manufacturing to 10 times its normal capacity and could increase it even further, said Mike Keenley, the president of the company’s U.S. arm. Ipca Laboratories – which until recently faced an FDA import ban on some of its facilities because of quality control violations – also is boosting production. Ipca is a key source of hydroxychloroquine listed by multiple distributors on the New Zealand drug website. Ajit Kumar Jain, the company’s joint managing director, did not respond to requests for comment.

India’s drug industry features a key vulnerability: about 70 percent of the active ingredients required to make its drugs are imported from China, said Ashok Kumar Madan, executive director of the Indian Drug Manufacturers’ Association. He said Indian drugmakers had stocks sufficient to weather disruptions in the supply of raw materials caused by China’s battle with the coronavirus earlier this year and that such supplies are once again arriving in India by air and by sea.