Are malaria drugs effective against COVID-19?
In late March, the U.S. Food and Drug Administration (FDA) authorized the emergency release of federal supplies of two drugs, typically used to treat malaria, for use with COVID-19 patients: hydroxychloroquine and chloroquine.
While it’s tempting to think of this as comforting news, the facts surrounding the use of these drugs for COVID-19 is more complicated than some reports imply, said Infectious Disease Physician David Pombo, MD, medical director of infection prevention at Cape Cod Healthcare.
For example, the FDA order only allows doctors to prescribe the drugs obtained from federal supplies for patients who would not be able to receive them as part of a clinical trial. Candidates must weigh more than 110 pounds and be screened for other conditions such as allergies, pregnancy, retinal disorders and diabetes.
Most importantly, the FDA action does not mean the government agency approved the drug as an effective COVID-19 treatment, Dr. Pombo said.
“People are getting confused between the emergency-use authorization and what might be FDA approval,” Dr. Pombo said. “It’s important to stress that there is no FDA approval. There’s no solid evidence that these medications are efficacious. And, there are risks to taking the drugs and those risks include potential for cardiac arrhythmia.”
Researchers have tested chloroquine, an antimalarial and autoimmune drug, as a tool to block the coronavirus from invading cells. They also have studied hydroxychloroquine in combination with the antibiotic azithromycin as a way to ease patients’ symptoms, according to the New York Times. But studies have either been small, or taken place in laboratories, Dr. Pombo said. As of now, he said, the drugs have no known benefit for COVID-19 patients beyond supportive care.
We asked Dr. Pombo to explain more about hydroxychloroquine and chloroquine and how patients might encounter them. His answers have been edited for length.
How are hydroxychloroquine and chloroquine administered?
They’re usually oral medications. Hydroxychloroquine is sometimes used in conjunction with azithromycin, an antibacterial antibiotic. Azithromycin is available intravenously as well.
How long does a patient take them?
It’s really up to the discretion of the physician. I've seen reports of prescribing for seven or 10 days, but the most common is five days.
The FDA mentions side effects such as stomach pain, nausea, vomiting and headache, among others. What’s the biggest worry?
The biggest concern with these drugs is potential cardiac arrhythmias. It's also recommended that patients be screened for certain high-risk comorbidities or other diseases and for medications they might be on. The FDA has a patient fact sheet about what needs to be evaluated before the drugs are prescribed. There is also a fact sheet for medical providers.
Are hydroxychloroquine and chloroquine rare or expensive?
They’re fairly common and have been around for a while. They’re not expensive.
One Chinese study found chloroquine might have an antiviral effect and you said hydroxychloroquine has anti-inflammatory properties. So why is there debate about using these drugs on COVID-19 patients?
Most antiviral effects have been shown primarily in vitro [meaning, in a test tube, not in patients]. There's not a lot of clinical data to support their use. So that's why there's some debate. Sometimes the concentrations of the drugs that are used in the test tube, so to speak, are higher than what's achievable in the body, or they have different interfering actions in the body. So, we're waiting for clinical studies that are done in larger numbers of patients.
If it were a perfectly innocuous therapy with no potential adverse side effects, I think there wouldn’t be so much worry. But both hydroxychloroquine and azithromycin have been known to cause cardiac arrhythmias separately. And so, when they’re combined, then you need to have monitoring and you need to acknowledge the risks.
What’s the Cape Cod Healthcare policy on these drugs?
Cape Cod Healthcare policy is that patients shouldn’t be routinely treated with it, but if they are, they have to be informed of the risks and they have to be monitored. Cape Cod Healthcare allows for physician discretion. I think some patients and doctors are feeling desperate and families want to know they haven’t left a potential medication underutilized. So I can understand that. However, if the medications are used, both the patient and the physician sign an acknowledgement that they’ve gone over the risks.