On Jun. 15, 2020, the U.S. Food and Drug Administration (FDA) warned health care providers about a newly discovered potential drug interaction related to the investigational antiviral drug remdesivir, which received emergency use authorization for treatment of hospitalized COVID-19 patients with severe disease.

The FDA revised fact sheet for health care providers state that co-administration of remdesivir and chloroquine phosphate or hydroxychloroquine sulfate is not recommended as it may result in reduced antiviral activity of remdesivir.