Chloroquine is used in the treatment of :

chloroquine is a rapidly acting erythrocytic schizontocide against all species of plasmodia; controls most clinical attacks in 1-2 days with disappearance of parasites from peripheral blood in 1-3 days. The mechanism of action of chloroquine is not completely known. It is actively concentrated by sensitive intraerythrocytic plasmodia: higher concentration is found in infected RBCs. By accumulating in the acidic vesicles of the parasite and because of its weakly basic nature, it raises the vesicular pH and thereby interferes with degradation of haemoglobin by parasitic lysosomes. Polymerization of toxic haeme to nontoxic parasite pigment hemozoin is inhibited by formation of chloroquine-heme complex. Heme itself or its complex with chloroquine then damages the plasmodial membranes. Clumping of pigment and changes in parasite membranes follow. Other related antimalarials like quinine, mefloquine, lumefantrine appear to act in an analogous manner. It has additional antiinflammatory local irritant and local anaesthetic propeies Essentials of medical pharmacology K D Tripathi Sixth dition Page no 821, 822: