<p>Chloroquine is used for malarial prophylaxis (as a suppressive) and in managing acute attacks of malaria. It is highly active against erythrocytic forms of P. vivax, P. malariae and P. falciparum. It influences Hb digestion by increasing intravesicular pH in malaria parasite cells and interferes with the nucleoprotein synthesis of the patient. It is also effective in extra intestinal amoebiasis. In RA chloroquine and more effectively hydroxychloroquine have a disease-modifying effect.</p>