Clioquinol

Clioquinol

Clioquinol is a quinoline derivative and a chelating agent that was primarily used as a topical antifungal and antiprotozoal agent. It is a member of the hydroxyquinolines family, which are known for their antifungal and antiprotozoal properties.

History

Clioquinol was first synthesized in the early 20th century and was widely used in over-the-counter creams, ointments, and suppositories for the treatment of various skin infections. However, its use was restricted in many countries in the 1970s due to concerns over potential neurotoxicity.

Pharmacology

Clioquinol acts by chelating metal ions, such as zinc and copper, thereby inhibiting the growth of fungi and protozoa. It is also thought to interfere with DNA replication and RNA transcription, further inhibiting the growth of these organisms.

Clinical Use

Clioquinol is used topically to treat skin infections caused by fungi or protozoa, such as athlete's foot, jock itch, and ringworm. It is also used in the treatment of amoebiasis, a parasitic infection caused by the protozoan Entamoeba histolytica.

Safety and Side Effects

The most common side effects of clioquinol include skin irritation, redness, and itching. In rare cases, it can cause more serious side effects, such as neurotoxicity, particularly when used in high doses or for prolonged periods.

Controversies

In the 1970s, clioquinol was linked to a neurological disorder known as subacute myelo-optic neuropathy (SMON) in Japan. This led to its withdrawal from the market in many countries. However, subsequent research has suggested that the incidence of SMON may have been due to high doses of clioquinol, and that the drug may be safe when used in lower doses.

Current Research

Recent research has suggested that clioquinol may have potential as a treatment for Alzheimer's disease and Huntington's disease. This is due to its ability to chelate metal ions, which are thought to play a role in the pathogenesis of these diseases.