The FDA has limited ability to monitor global supply chains in the pharmaceutical industry, some experts say. Jacquelyn Martin/Associatd Press/File 2018/Associated Press

WASHINGTON — 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 the public is 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 has experienced spikes in demands for fentanyl and other sedatives needed for patients experiencing respiratory failure who are placed on ventilators. 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, 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 US 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. If supply conditions worsen, 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 Drug Enforcement Administration to win permission for manufacturers to fill more 50-milliliter vials, he said.

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

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.

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 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 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 the US supply in a matter of weeks.

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 overseas, with 48 percent in India and China, according to industry estimates. China shut down drug manufacturing facilities during its coronavirus lockdown, but some are expected to come back on line in coming weeks and months.

The shortages show how a lack of basic information is hurting US planning and readiness for a variety of disasters, said Stephen Schondelmeyer, a professor of pharmaceutical economics 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.’’