The US Food and Drug Administration (FDA) has issued an emergency use authorization for chloroquine and hydroxychloroquine to treat patients hospitalized with Covid-19.
Both the drugs are used to treat malaria and other conditions, reports the CNN.
US President Donald Trump has called them as game changers.
However, little scientific evidence exists that chloroquine, or its closely-related analogue hydroxychloroquine, are effective in treating Covid-19.
The authorization came in a letter dated Saturday, but the US Department of Health and Human Services (HHS) acknowledged the FDA's action in a Sunday news release.
"Anecdotal reports suggest that these drugs may offer some benefit in the treatment of hospitalized COVID-19 patients.The safety profile of these drugs has only been studied for FDA approved indications, not COVID-19," the HHS statement read.
The FDA limited the scope of its authorization to drugs supplied from the Strategic National Stockpile.
The HHS announced that two pharmaceutical companies -- Bayer and a division of Novartis -- had donated the drugs to the stockpile.