5-Chloro-7-iodo-quinolin-8-ol (
Clioquinol) is a halogenated
8-hydroxyquinoline that was used in 1950-1970s as an oral anti-parasitic agent for the treatment and prevention of
intestinal amebiasis. However in the 1970s oral
Clioquinol was withdrawn from the market due to reports of neurotoxicity in Japanese patients. Recently, reports have demonstrated that
Clioquinol has activities beyond its use as an antimicrobial. For example,
Clioquinol inhibits the function of the
proteasome and displays preclinical efficacy in the treatment of
malignancy. In addition, due to its ability to bind
copper and dissolve
beta-amyloid plaques in the brain,
Clioquinol has been investigated for the treatment of
Alzheimer's disease. As such, efforts are underway to repurpose
Clioquinol. In light of the reemergence of oral
Clioquinol, we review the toxicology of this compound in animals and humans with an emphasis on its neurotoxicity. Such information will aid in the design of clinical trials of oral
Clioquinol for new indications such as
cancer therapy.