What is chloroquine, and why do people think it treats coronavirus?

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Not long after President Donald Trump mentioned them as “a game changer” in the fight against the coronavirus, two drugs long used to fight malaria began to grab headlines.

A Fox News story highlighted a man who credited hydroxychloroquine with saving his life. A Phoenix couple, after seeing television news reports about a related drug, chloroquine, instead swallowed chloroquine phosphate, an additive used to clean fish tanks, according to BuzzFeed.

The couple quickly fell ill and the man died, his wife explaining to NBC News that the two had been afraid of getting the virus.

The initial reaction from the medical community, including experts in Florida: The drugs’ effect in coronavirus cases is not fully known — far from it — and no one should be taking them without medical supervision.

What’s more, a run on the two medicines has led to nationwide shortages, which are affecting the people who rely on them every day to treat autoimmune diseases like lupus or rheumatoid arthritis.

But the Washington Post reported Thursday that the severity of the pandemic has led New York state officials and the Food and Drug Administration to embark on an extraordinary “human experiment” to study the drugs’ impact on the coronavirus. The effort, being conducted with “unprecedented speed and scale,” involves distributing tens of thousands of doses to seriously ill patients for an “observational” trial that will gauge the drugs’ effectiveness and safety when used in this way, the Post reported.

The newspaper cited health experts and an unnamed state health official. It said the study would involve “hydroxychloroquine and chloroquine in combination with the antibiotic azithromycin.”

Some health experts expressed concern about safety risks such as fatal heart arrhythmia and vision loss, the report said.

Chloroquine and hydroxychloroquine have shown promising results in early studies among coronavirus patients in France, China and South Korea because of their antiviral effects, said Liwang Cui, a molecular parasitologist with the University of South Florida. But the sample sizes, he said, were small and much more research needs to be done.

“Great caution needs to be used,” said Jay Wolfson, a professor at USF’s College of Public Health and an expert on health care policy. “It should only be used with a physician’s specific prescription and recommendation. Many people who are using other prescriptions can experience serious complications and adverse effects.”

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Barbara Santevecchi, a clinical assistant professor of infectious diseases at the University of Florida’s College of Pharmacy, said the two drugs “appear to have activity against SARS-CoV-2,” the virus caused by the coronavirus, “but we need more information from treatment in humans, such as in clinical trials, to come to a firm conclusion about these agents."

Santevecchi added: “New data seems to be emerging every day that is providing more evidence for physicians and health care providers to determine the best treatment for COVID-19.”

Historically, chloroquine and hydroxychloroquine have been used to treat and prevent malaria. Hydroxychloroquine is also used as an immune-suppressing drug for patients with lupus and rheumatoid arthritis. Both drugs require a prescription from a physician.

Stories are circulating of people calling in favors with friends who are physicians or dentists to get the drugs, which is dangerous, Wolfson said.

“People should be instructed not to be cowboys or cowgirls and certainly not use any medications that they had in their medicine cabinet for years or to borrow those from other people or to get things online, because these days, no one will know exactly what they are,” he said. “You can do far more damage than good.”

Pharmacist Dipal Patel, the owner of Acme Pharmacy on Fowler Avenue in Tampa, has received some calls from residents asking about these medications, but is not seeing a shortage yet.

“Chloroquine isn’t really that popular in the U.S.," he said. “Sometimes travelers get it before a trip to Asia or Africa.”

Hydroxychloroquine is more popular because it is used to treat other autoimmune ailments, he said.

Both drugs "are effective in treating against malaria but there are a lot of side effects,” he said. Those include joint and muscle pain, nausea, vomiting, abdominal cramps and headaches.

The reported shortages in pharmacies are mostly because the drugs aren’t manufactured in large amounts in the U.S.; there has never been such a high demand, Patel said.

“One pharmacy may order one or two bottles per month. If I ordered five or six, I would be taking stock away from other pharmacies,” he said.

Chloroquine was discovered in 1934 in a Bayer laboratory and was widely used in African countries to treat and prevent malaria, said Cui, the USF molecular parasitologist. He said the effectiveness of the drug waned over time as some strains of malaria became resistant to it, so other drugs like Primaquine became available.

Hydroxychloroquine was approved for use in the U.S. in 1955 as a malaria prevention and treatment drug.

Both drugs are listed on the World Health Organization’s “Model List of Essential Medicines."

“Chloroquine seems to be having a strong response to the coronavirus’ inflammatory response,” Cui said. “It’s a good drug to try when it can be managed. It needs to be maintained at a certain level. Too much makes a person vulnerable, and people can die from it.”

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