Chloroquine Products | Cleanchem - Chloroquine is an antimalarial drug used for the prevention and treatment of malaria caused by Plasmodium vivax, P. malariae, and P. ovale. It is also used in autoimmune diseases like rheumatoid arthritis and lupus erythematosus. It works by interfering with parasite metabolism in red blood cells. However, resistance in P. falciparum limits its effectiveness in some regions.