Hydroxychloroquine

Hydroxychloroquine sulfate is sold under the drug names Plaquenil and Ercoquin and used as a treatment or prophylaxis of malaria. Hydroxychloroquine is also used to treat lupus erythematosus and rheumatoid arthritis. Chloroquine is also given as a drug in the form of chloroquine phosphate under the drug name Aralen for the same indications. Overdose of chloroquine phosphate can cause acute poisoning and death. Hydroxychloroquine sulfate is a derivative of chloroquine phosphate that has been demonstrated to be 40% less toxic than chloroquine phosphate in animals, but prolonged and overdose usage can still cause poisoning.

Hydroxychloroquine sulfate is being tested in clinical trials for COVID-19 and has been shown to inhibit SARS-CoV-2 infection in vitro, in Vero E6 cells in culture.