Used primarily in the treatment of hyperkinetic movement disorders, particularly chorea associated with Huntington’s disease. It helps reduce involuntary movements by depleting monoamine neurotransmitters such as dopamine, serotonin, and norepinephrine in the brain. Its mechanism involves inhibition of the vesicular monoamine transporter 2 (VMAT2), which leads to decreased storage and increased breakdown of these neurotransmitters. Due to its effect on dopamine regulation, it is also sometimes used off-label for conditions like tardive dyskinesia and certain psychiatric disorders involving hyperdopaminergic states. The drug is valued for its ability to improve motor control and quality of life in affected patients, though careful monitoring is required due to potential side effects like depression and sedation.