The drugs, approved decades ago for several uses, including the treatment of malaria, have shown promise in small studies and in hospitals for treating COVID-19 but other studies have suggested harmful side effects or no evidence they work against the new disease.
The FDA said in the warning that it was aware of reports of heart rhythm problems seen in some patients with COVID-19 treated with hydroxychloroquine or chloroquine, often in combination with azithromycin and other QT prolonging medicines.
The increase in use of the medicines spurred the agency to remind medical workers and patients of the possible side effects. The drugs can cause abnormal health rhythms such as QT interval prolongation and a rapid heart rate.
The risks “may increase when these medicines are combined with other medicines known to prolong the QT interval, including the antibiotic azithromycin,” according to the FDA.
“Patients who also have other health issues such as heart and kidney disease are likely to be at increased risk of these heart problems when receiving these medicines,” it added.
“We are also aware of increased use of these medicines through outpatient prescriptions. Therefore, we would like to remind health care professionals and patients of the known risks associated with both hydroxychloroquine and chloroquine.”
No drugs have been approved for the treatment of COVID-19 by the FDA but the agency last month authorized the emergency use of the anti-malarials for patients hospitalized with COVID-19.
In the updated guidance, the FDA said it was “warning the public” that the use of hydroxychloroquine and chloroquine for treating COVID-19, either alone or combined with azithromycin, should only be in clinical trials or for treating certain patients in hospitals.
Dr. Stephen Hahn, the FDA commissioner, said in a statement, “We understand that health care professionals are looking for every possible treatment option for their patients and we want to ensure we’re providing them with the appropriate information needed for them to make the best medical decisions.”
“While clinical trials are ongoing to determine the safety and effectiveness of these drugs for COVID-19, there are known side effects of these medications that should be considered,” he added.
Clinical trials analyzing the safety and efficacy of hydrxychloroquine and chloroquine are underway in the United States and a number of other countries.
The potential promise of the drugs has been promoted by some, including President Donald Trump, prompting others to note the possible side effects the drugs are known to have when used to treat malaria, lupus, and rheumatoid arthritis and the dearth of studies and trials showing efficacy against COVID-19.
A doctor who was recently demoted from directing an agency inside of the Department of Health of Human Services said Wednesday that he was shifted because of his stance against hydroxychloroquine.
A panel created by the National Institutes of Health earlier this week recommended against using hydroxychloroquine in combination with azithromycin, an antibiotic known as Z-Pak. The panel said there’s not enough information to recommend for or against using hydroxychloroquine alone.
An observational study conducted by researchers of hundreds of patients at Veterans Health Administration hospitals found no evidence hydroxychloroquine was effective against COVID-19, but Secretary of Veterans Affairs Robert Wilkie said most of the patients in the study “were in the last stages of life,” he said.
The agency has seen the drug work in middle-aged and younger patients, he added.
Some in the medical community say hydroxychloroquine is most effective when given before patients see severe cases of COVID-19 and when used in conjunction with other drugs.
A New York doctor told The Epoch Times’s sister company NTD that over 400 of his high-risk patients recovered after he used a three-drug regimen of hydroxychloroquine, azithromycin, and zinc.
“If it was peacetime, we could spend months doing studies, let’s say for four months doing a clinical study, figuring out which bullet is the shiniest and works the best, which medication has the least side effects.” Dr. Vladimir Zelenko said. “And then we can use it. Unfortunately, we don’t have time.”
“The virus is inside the cell, the zinc cannot get inside the cell for biochemical reasons, so the hydroxychloroquine opens the door and lets the zinc in. That’s all it does, in this context,” he added, noting azithromycin protects the patient from secondary infections.