The FDA is warning healthcare providers about a newly discovered potential drug interaction related to the investigational antiviral drug remdesivir, which has received emergency use authorization for the treatment of hospitalized COVID-19 patients with severe disease. Based on a recently completed non-clinical laboratory study, the FDA is revising the fact sheet for healthcare providers that accompanies the drug to 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 or lead to possible allergic reactions. Read the FDA statement.