The FDA cautioned doctors shouldn't prescribe the drug to treat COVID-19 out of a hospital setting or clinical trial.

WASHINGTON — The U.S. Food and Drug Administration is warning doctors against prescribing a malaria drug widely touted by President Donald Trump for treating the new coronavirus outside of hospitals or research settings.

In an alert Friday, regulators flagged reports of serious side effects and death among patients taking hydroxychloroquine and the related drug chloroquine. The drugs, also prescribed for lupus, can cause a number of side effects, including heart rhythm problems, severely low blood pressure and muscle or nerve damage.

In one such report, doctors at a New York hospital said that heart rhythm abnormalities developed in most of the 84 coronavirus patients treated with hydroxychloroquine and the antibiotic azithromycin, a combo Trump has promoted.

Last month, the FDA authorized emergency use of the malaria drugs for hospitalized patients with COVID-19 who aren’t enrolled in ongoing clinical trials. But regulators said they are investigating life-threatening side effects reported with the drugs to poison control centers and other health authorities.

Calls to U.S. poison control centers involving the malaria drugs have recently jumped 50%, from 52 calls in March 2019 to 79 last month, according to Dr. Christopher Hoyte of the Rocky Mountain Poison Center in Denver, Colorado.

The problems reported include irregular heart rhythms, seizures, nausea and vomiting, Hoyte said.

Trump has repeatedly touted hydroxychloroquine during his regular coronavirus briefings, calling it a “game-changer” and suggesting its skeptics would be proved wrong. He has offered patient testimonials that the drug is a lifesaver.

“It is important that health care providers are aware of the risks of serious and potentially life-threatening heart rhythm problems that can occur with these drugs,” the FDA said in a statement.

What should patients and parents/caregivers do?

The FDA provided the following information on its website Friday.

Patients taking hydroxychloroquine or chloroquine for FDA-approved indications to treat malaria or autoimmune conditions should continue taking their medicine as prescribed. The benefits of these medicines outweigh the risks at the recommended doses for these conditions. Do not stop taking your medicine without first talking to your health care professional, and talk to them if you have any questions or concerns.

Be aware that there are no proven treatments for COVID-19 and no vaccine. If you are receiving hydroxychloroquine or chloroquine for COVID-19 and experience irregular heartbeats, dizziness, or fainting, seek medical attention right away by calling 911.

Do not buy these medicines from online pharmacies without a prescription from your health care professional. Consumers should not take any form of chloroquine that has not been prescribed for them by a healthcare professional. Serious poisoning and death have been reported after mistaken use of a chloroquine product not intended to be taken by humans. If you have these medicines in your home, keep them in childproof containers out of the reach of children to prevent accidental poisoning.

What should healthcare professionals do?

The FDA recommends healthcare professionals should have an initial evaluation and monitor a patient when using hydroxychloroquine or chloroquine under the EUA or in clinical trials that investigate these medicines for the treatment or prevention of COVID-19.

However, be aware that hydroxychloroquine or chloroquine can:

cause QT prolongation

increase the risk of QT prolongation in patients with renal insufficiency or failure

increase insulin levels and insulin action causing an increased risk of severe hypoglycemia

cause hemolysis in patients with Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency

interact with other medicines that cause QT prolongation even after discontinuing the medicines due to their long half-lives of approximately 30-60 days

If a healthcare professional is considering the use of hydroxychloroquine or chloroquine to treat or prevent COVID-19, the FDA recommends checking www.clinicaltrials.gov for a suitable clinical trial and consider enrolling the patient.

How to report side effects from hydroxychloroquine and chloroquine?