On June 15, 2020, FDA released a safety alert regarding the possible reduced antiviral activity of remdesivir when administered concomitantly with hydroxychloroquine sulfate or chloroquine phosphate. In-vitro data suggests that chloroquine decreases metabolic activation and antiviral activity of remdesivir.
FDA has revised the fact sheet to include a statement that co-administration of remdesivir and hydroxychloroquine sulfate and chloroquine phosphate is not recommended. FDA is unaware of cases with reduced activity in the clinical setting, but is continuing to evaluate data with remdesivir use. Remdesivir is an antiviral agent that recently has been issued for Emergency Use Authorization (EUA) to treat COVID-19 based on preliminary trials showing decreased average time to recovery in patients treated with remdesivir. The EUA requires remdesivir fact sheets be made available to all health care providers, patients, and caregivers. The fact sheet includes information on possible adverse effects, such as elevated liver enzymes or allergic reactions. FDA recommends health care providers refer to the most updated fact sheet when prescribing remdesivir.
Health care providers and patients should report any side effects and adverse events related to remdesivir, hydroxychloroqine, or chloroquine to FDA's MedWatch Safety Information and Adverse Event Reporting by completing the online format www.fda.gov/medwatch/report.htm or by mailing or faxing in a downloaded form.
Additional information is available at the following links: