What's the MOA for Xenazine (tetrabenazine)?

Xenazine is thought to help control involuntary body movements in Huntington’s disease by lowering levels of brain chemical messengers (neurotransmitters) that control muscle movement.

Xenazine (tetrabenazine) is in a class of medications known as vesicular monoamine transporter 2 (VMAT2) inhibitors.

How does Xenazine work?

The mechanism of action of Xenazine is thought to be due to its binding to the human vesicular monoamine transporter type 2 (VMAT2).

• VMAT2 transports the chemical messengers (neurotransmitters) serotonin, dopamine, norepinephrine, and histamine into areas for storage in brain nerve cells.
• By binding to and inhibiting VMAT2, Xenazine decreases uptake of the neurotransmitters into synaptic vesicles and depletes neurotransmitter stores, particularly dopamine.

In a nerve cell (neuron), synaptic vesicles are areas that store various neurotransmitters to be released when a nerve impulse arrives and initiates a bodily movement. By blocking VMAT2, a reduced amount of neurotransmitter is available and unwanted body movements decrease.

Does Xenazine cure Huntington’s disease?

Xenazine is a prescription medicine used to help reduce involuntary movements of Huntington’s disease but is not a cure and does not help with thinking (cognition) or emotional problems.

Huntington's disease is a rare, inherited disease that causes nerve cells in the brain to break down and die, leading to involuntary movements (chorea). Chorea usually affects hands and facial muscles first and may begin as mild movements. Later this can progress to larger, jerky or twisting movements of the arms, legs and body.

Body movements are controlled by nerve cells (neurons) found in the brain. Nerve cells talk to each other (communicate) by passing chemical messengers (neurotransmitters) from one cell to cell to another. In certain movement disorders like Huntington’s chorea, lowering the amount of chemical messengers helps to relieve uncontrolled movements due to the disease.

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What are the most commonly reported side effects with Xenazine?

In studies, commonly reported side effects included:

• sleepiness (sedation)
• trouble sleeping (insomnia)
• depression
• tiredness (fatigue)
• anxiety
• restlessness
• agitation
• nausea.

Learn more: Dosing, warnings and drug interactions with Xenazine

This is not all the information you need to know about Xenazine (tetrabenazine) for safe and effective use and does not take the place of your doctor’s directions. Review the full product information and discuss this information and any questions you have with your doctor or other health care provider.