Why isn't hydroxychloroquine aggressively used off-label in Covid patients?

It's already FDA-approved for arthritis inflammation. It's been shown repeatedly to treat coronavirus in humans in China (400mg twice a day the first day, 200mg twice a day for the next four days,) as well as treating SARS in newborn mice and petri dishes of lung cells.

Why would Italy allow patients to die anyway instead of just trying hydrochloroquine?

Do we have any figures on infection and fatality rates for patients who take hydrochloroquine for arthritis or malaria prophylaxis in Central America compared to the general population?