Antioxidants as a treatment of tardive movement disorders

Tardive dyskinesia (TD) is characterized by repetitive, involuntary, purposeless movements of the tongue, lips, face, trunk, and extremities that occur in patients treated with long-term dopaminergic antagonists and following exposure to L-dopa, amphetamine, metoclopramide, cinnarizine, flunarizine and other substances. The term tardive dyskinesia refers to: classical TD (bucco-lingual-masticatory triad), tardive akathisia, tardive dystonia, tardive tremor and other tardive extrapyramidal subsyndromes. The mechanisms of TD remain unclear, although pathophysiologic theories have proposed mechanisms such as dopamine receptor supersensitivity, the degeneration of cholinergic striatal interneurons, γ-aminobutyric acid (GABA) depletion, and an excess of free radicals. Though a wide range of medications for the treatment of TD had been studied, management of this distressful side effect remains a significant problem for patients and a therapeutic conundrum for physicians. According to current concepts, antioxidants such as vitamins and other antioxidative agents may be considered as active components of putative therapies because they inhibit free radical distractive activities. This chapter is focused on evidence from clinical and basic science studies that support the role of antioxidants (vitamins B₆ and E, Kamishoyo- san, omega-3, ginkgo biloba, piracetam, curcumin, resveratrol and others) as potential neuroprotective compounds and effective medications for the prevention and management of TD.