The drugs for battling Ebola might already exist. A screening of over 2,600 compounds reveals how the antidepressant Zoloft and a drug used to treat heart disease could be repurposed for the Ebola virus. The majority of mice treated with these drugs survived their infection. 

There are lots of vaccines and drugs being investigated right now for preventing or treating Ebola virus infections – but not one has been approved so far. Because both drugs in the study have already been approved by the US Food and Drug Administration, their safety record means that they could potentially readily enter clinical testing for Ebola. The findings were published in Science Translational Medicine this week. 

A team led by Gene Olinger from the US Army Medical Research Institute of Infectious Diseases tested 2,635 FDA-approved drugs, common molecular probes and dietary supplements (like vitamins, minerals, food additives) against Zaire ebolavirus. They identified 30 promising drugs that had some anti-Ebola activity in a culture. 

After a series of experiments, they further narrowed down the candidate list to the best two: the commonly used antidepressant Zoloft and a calcium channel blocker called Vascor, which is used to treat heart disease. The two belong to the same class of drugs. Zoloft works by blocking the reuptake of the brain chemical serotonin, Discover explains, and Vascor treats high blood pressure by keeping calcium from entering cells lining blood vessel walls to keep the vessels relaxed and dilated.

Both protected mice from their Ebola infections by blocking the virus' entry into the hosts’ cells. For each of the drugs, 10 mice were infected, then treated within an hour, and their survival was monitored for 28 days after virus exposure. Seven of the mice treated with Zoloft survived infection (that’s 70 percent), and all of the mice treated with Vascor lived. All of the infected control mice (those who weren’t treated) were dead by day 9. 

The concentrations of the drugs tested were higher than those that people would normally take, and we don’t know if these larger doses come with toxic side effects. Not to mention, well, it was a mouse study. But based on experiments in cell cultures, both drugs are effective against two different species of the virus, Zaire ebolavirus and Sudan ebolavirus, as well as three closely-related viruses. And repurposing approved drugs, they write, might reduce the risk, time, and cost, at least in theory.