The U.S. Food and Drug Administration (FDA) approved Austedo (deutetrabenazine) in 2017 for the treatment of chorea associated with Huntington’s disease (HD), according to a press release from its maker, Teva.

Chorea is a motion disorder characterized by involuntary muscle movement. The cause is believed to be problems with the regulation of chemical signals released by neurons.

Neurons contain information that determines muscle movement. In order for the information to reach a muscle, it has to be passed through a long line of neuron cells. This requires each neuron in the line to release chemical molecules.

For the information to be passed from one neuron cell to another, sacs known as vesicles must gather up and transport the chemical molecules, which they release near an adjacent neuron cell.

The involuntary muscle movement in Huntington’s involves the excessive release of one chemical molecule: dopamine.

How does deutetrabenazine (Austedo) work?

Deutetrabenazine works the same way as another FDA-approved drug, Xenazine (trabenazine). Both inhibit the vesicles that carry dopamine to the place between two neurons where it is released. This kind of vesicle is known as a vesicular monoamine transporter 2 (VMAT2).

Both drugs bind to VMAT2, reducing the amount of dopamine released from neurons and dialing back the stimulation of adjacent neurons. This prevents the overstimulation of muscles that is seen in chorea.

Tetrabenazine has a short half-life in the body, which means its effects wear off within hours of someone taking it. Deutetrabenazine has a longer half-life. That’s because scientists altered the its chemical structure to prolong its effect.

Studies with Deutetrabenazine (Austedo)

Deutetrabenazine’s ability to reduce chorea in Huntington’s patients was assessed in a Phase 3, randomized, double-blind, placebo-controlled clinical trial (NCT01795859).

Researchers studied 90 Huntington’s patients with chorea who were able to move about. They assessed the patients’ total maximal chorea (TMC) scores nine and 12 weeks after their treatment began.

The TMC scores of patients receiving deutetrabenazine improved. But a week after they stopped taking the medication, their scores reverted back to their initial values.

Side effects of Deutetrabenazine

Deutetrabenazine can increase the risk of depression, and suicidal thoughts and behavior, in Huntington’s patients.

VMAT2 inhibitors not only can worsen mood, but also a person’s ability to function and their cognition.

The drug is not recommended for anyone with a liver condition or anyone taking a monoamine oxidase inhibitor for depression.

Patients’ most common adverse reactions to deutetrabenazine during the clinical trial were sleepiness, diarrhea, dry mouth, and fatigue.