chloroquine is very common in places where there is Malaria, it is not exactly something that can be used without care :
Common side effects include muscle problems, loss of appetite, diarrhea, and skin rash.[1] Serious side effects include problems with vision, muscle damage, seizures, and low blood cell levels.
and it is cheap
The wholesale cost in the developing world is about US$0.04.[8] In the United States, it costs about US$5.30 per dose.[1]
Though nearly a dozen drugs to treat coronavirus are in clinical trials in China, just one—remdesivir, an antiviral that was in trials against Ebola and the coronavirus MERS—is in full-on trials in the US. Nothing has been approved by the Food and Drug Administration. So a promising drug would be great—and even better, chloroquine isn’t new. Its use dates back to World War II, and it’s derived from the bark of the chinchona tree, like quinine, a centuries-old antimalarial. That means the drug is now generic and is relatively cheap. Physicians understand it well, and they’re allowed to prescribe it for anything they want, not just malaria.
