Experts aren’t sure exactly how Ingrezza works but suggest it blocks a protein transporter called vesicular monoamine transporter 2 (VMAT2), which is responsible for regulating the uptake of neurotransmitters such as dopamine. The abnormal functioning of dopamine is thought to be a cause of tardive dyskinesia (TD). By blocking VMAT2, Ingrezza reduces the uptake of dopamine, causing a decrease in symptoms of TD.

Ingrezza may also regulate the uptake of other neurotransmitters, such as noradrenaline and serotonin. All these neurotransmitters have various functions within the body but dopamine, in particular, plays a role in movement as well as pleasure, motivation, and learning.

Ingrezza may be used to treat adults with tardive dyskinesia (TD). Although some reduction in symptoms of TD may be noticed within a week or two, it can take up to 32 weeks to have an effect. Side effects include fatigue, sleepiness, changes in balance, and a dry mouth.