Quinacrine is a synthetic medication originally developed as an antimalarial agent. It has also been used for various other medical purposes, including the treatment of giardiasis, lupus, and rheumatoid arthritis.

Quinacrine works by interfering with the function of parasites or modulating immune responses, depending on the condition being treated. Although less commonly used today due to the availability of newer drugs, it remains of interest in certain clinical and research settings. Potential side effects include gastrointestinal discomfort, skin discoloration, and, rarely, neurological symptoms, so its use is typically monitored by healthcare providers.