Chloroquine: Modes of action of an undervalued drug

• Chloroquine, an antimalarial drug, can also be used in the manipulation of the immune system.
• This review demonstrates the multitude of actions displayed by CQ, dependent on lysosome dysfunction and also pH-independent mechanisms.
• Chloroquine administration ameliorates rheumatoid arthritis, systemic lupus and viral infections.

For more than two decades, chloroquine (CQ) was largely and deliberately used as first choice drug for malaria treatment. However, worldwide increasing cases of resistant strains of Plasmodium have hampered its use. Nevertheless, CQ has recently been tested as adjunct therapy in several inflammatory situations, such as rheumatoid arthritis and transplantation procedures, presenting intriguing and promising results. In this review, we discuss recent findings and CQ mechanisms of action vis-à-vis its use as a broad adjunct therapy.