With little evidence that the malaria drugs hydroxychloroquine and chloroquine can prevent or treat COVID-19, the U.S. Food and Drug Administration has given emergency approval to distribute millions of doses of the medicines to hospitals across the country.
"These drugs will be distributed from the Strategic National Stockpile to states for doctors to prescribe to adolescent and adult patients hospitalized with COVID-19 as appropriate, when a clinical trial is not available or feasible," the FDA said in a statement released March 28.
Use of the two drugs is controversial, however, because of widely recognized and potentially serious side effects. Under the FDA's plan, fact sheets outlining "the known risks and drug interactions" of hydroxychloroquine and chloroquine will be made available to clinicians, the agency said.
As the number of COVID-19 cases and deaths continues to surge in the United States, doctors are left without either a vaccine or proven medication to curb severe illness.
Chloroquine's potential use as a COVID-19 therapy got a big boost last week when President Donald Trump extolled its supposed efficacy during a White House news briefing. But that was quickly followed by statements from the nation's top infectious disease expert, Dr. Anthony Fauci, who downplayed chloroquine's effectiveness, citing a dearth of evidence.
Indeed, the primary support for the malaria drug's efficacy comes from a French study of just 20 patients with COVID-19 who were given hydroxychloroquine plus the antibiotic azithromycin. Six of the patients who received the combination recovered, as did seven of 14 patients who received hydroxychloroquine alone, according to the study published online March 20 in the International Journal of Antimicrobial Agents.
"Despite its small sample size, our survey shows that hydroxychloroquine treatment is significantly associated with viral load reduction/disappearance in COVID-19 patients and its effect is reinforced by azithromycin," the French team wrote.
But another study cast doubt on the French findings. According to Bloomberg News, that study involved 30 Chinese COVID-19 patients and found no difference in viral clearance between the 15 patients who got hydroxychloroquine and 15 who did not take the drug.
Still, in a March 28 letter leading to the FDA's authorization of hydroxychloroquine and chloroquine for COVID-19, agency chief scientist Denise Hinton noted that, "based upon limited in-vitro and anecdotal clinical data in case series, chloroquine phosphate and hydroxychloroquine sulfate are currently recommended for treatment of hospitalized COVID-19 patients in several countries."
Given the lack of viable treatment alternatives, "it is reasonable to believe that chloroquine phosphate and hydroxychloroquine sulfate may be effective in treating COVID-19," Hinton added.
But other experts worry that the known and sometimes dangerous side effects of the two drugs could emerge in thousands of patients.
One of the biggest side effects involves alterations in the heart's rhythm, said Dr. Michael Ackerman, a pediatric cardiologist at the Mayo Clinic in Rochester, Minn. The malaria drugs are tied to a prolongation in the QTc -- a measurement of the heart's electrical recharging system. Prolonged QTc can trigger sudden cardiac death.
"Correctly identifying which patients are most susceptible to this unwanted, tragic side effect and knowing how to safely use these medications is important in neutralizing this threat," Ackerman said in a Mayo Clinic news release.
His team conducted a study outlining the danger, and offering guidance to doctors who might be caring for COVID-19 patients who receive hydroxychloroquine or chloroquine.
"Right now, it is the Wild West out there, ranging from doing no QTc surveillance whatsoever and just accepting this potential tragic side effect as part of 'friendly fire,' to having ECG technicians going into the room of a patient with COVID-19 daily, exposing them to coronavirus and consuming personal protective equipment," Ackerman said.
His team said that sensors could help doctors monitor patient's heart rhythms remotely, lessening the danger to health care workers.
Such monitoring would help pinpoint the small minority of patients who would be at higher odds for the arrhythmia, Ackerman said.
"Importantly, the vast majority of patients -- about 90 percent -- are going to be QTc cleared with a 'green light go' and can proceed, being at extremely low risk for this side effect," he said.
Clinical trial to come
According to the Washington Post, another known side effect of hydroxychloroquine or chloroquine use is the vision-robbing condition known as retinopathy, but that's typically something that only develops over the long-term. For now, the FDA is advising the use of the malaria drugs only for short-term treatment of COVID-19.
The answer to whether or not the malaria medicines can prevent COVID-19 could be on the way. Researchers at the University of Washington School of Medicine and New York University Grossman School of Medicine are launching a two-month clinical trial they hope will include over 2,000 participants. All of the participants will be close contacts of people who have or are thought to have COVID-19 -- meaning they are at high risk of developing the illness.
"We currently don't know if hydroxychloroquine works, but we will learn in as short a timeframe as possible what the outcome is," principal investigator Ruanne Barnabas said in a UW news release. She's associate professor of global health in the university's schools of Medicine and Public Health. The results are expected by this summer.
For now, drug giants Novartis and Bayer are each contributing millions of doses of hydroxychloroquine or chloroquine to the National Stockpile, the Post reported, and the FDA has already approved the distribution of hundreds of thousands of doses to hospitals in New York, the current epicenter of the coronavirus pandemic.
All of the experts urged against members of the public "self-medicating" with the malaria drugs or chemicals that might contain them.
Real tragedies could result: In one much publicized case, a couple living in Phoenix mixed fish-tank cleanser -- with hydroxychloroquine as one of its ingredients -- with soda and drank the mixture, hoping it would ward off COVID-19. The "medicine" proved poisonous, killing the man and landing the woman in the hospital, the Post reported.
The U.S. Centers for Disease Control and Prevention has more on the new coronavirus.
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