Editor's Note: The FDA on April 24 cautioned against the use of hydroxychloroquine or chloroquine "outside of the hospital setting or a clinical trial." The agency said it is "aware of reports of serious heart rhythm problems in patients with COVID-19" when treated with the drugs, and that they have not been shown to be "safe and effective for treating or preventing COVID-19."



One of the reasons health professionals are so worried about the coronavirus pandemic is that there is no specific medicine to treat or prevent the disease — if a patient gets sick, all doctors can do is provide supportive treatment to help them breathe. But in Thursday's coronavirus task force briefing from the White House, President Trump touted two preexisting treatments that have been floated as potential ways to help patients fight back.

Both drugs are still in clinical trials for coronavirus. But CBS News medical contributor Dr. David Agus joined "CBS Evening News" anchor Norah O'Donnell to break down what we know about the medications.

Read Norah O'Donnell's interview with Dr. Agus below.

Norah O'Donnell: Dr. David Agus, so good to have you. One of the drugs is actually a half-century-old anti-malaria drug. How does it work?

Dr. David Agus: It's pretty wild, right? Hydroxychloroquine is used for malaria and rheumatoid arthritis, and it works by two mechanisms: One is it blocks virus, and the second is it tempers down inflammation — both of which play a role probably in how it's benefiting patients with COVID-19.

The other drug that the president mentioned was created to treat Ebola. How would that work?

So that is another antiviral. This one is intravenous — compared to the first one, hydroxychloroquine, is oral — and remdesivir is an intravenous drug that blocks the virus. You know, this is a virus, it's not alive. The virus actually goes into our cells and uses our own machinery to divide, and drugs like remdesivir can inhibit those processes, enabling the virus to stop dividing, and that's how we benefit from it.

If you have COVID-19 right now, what do these potential treatments mean for you?

If somebody has COVID-19 now, I want them to talk to their doctor about the potential role of using hydroxychloroquine today. It is an FDA-approved drug for other indications and they could write a prescription today for this drug and use it in the right setting. That doesn't mean every patient needs to be on it, but it's a discussion to have with your doctor, there is hope. And this drug is hope personified to every person with the disease.

We saw cases spike in just the last 24 hours. Where are we on this curve?

I'm optimistic. I'm hopeful with the behavior changes our country has made, as well as with these medications announced today, that we're really at a new point and a point where I could see, at some point, light at the end of the tunnel.

What's the most significant behavioral changes you've made?

You know, my children and my wife, we're staying home, and we're going out for things like this where it's a very controlled environment, we're eating together as a family. Both of my children are home from college, and every night I have dinner with them. To me, it's a gift — I mean, you have to find positive in some small places in this horrible tragedy that hit our country.