VMAT2 inhibitors

VMAT2 inhibitors (vesicular monoamine transporter-2 inhibitors) are used to treat movement disorders such as Huntington’s disease or tardive dyskinesia. In Huntington’s disease the uncontrollable movements may start out mild as fidgeting or quick movements of the feet and hands and then, as the disease progresses, the movements can become bigger and can involve flailing of arms and legs. Tardive dyskinesias are involuntary, repetitive body movements that can develop as a side effect of long term use of a group of medicines called neuroleptics. VMAT2 inhibitors reduce unwanted body movements for these conditions.

How they work

Body movement or motor function is controlled in the brain by nerve cells (neurons) which speak to each other by passing chemical messengers (neurotransmitters) from one nerve cell to another nerve cell. In movement disorders there can be a problem with this system and by lowering the amount of chemical messengers between the nerve cells you relieve the uncontrolled movements. A protein called VMAT2 controls how much chemical messenger is stored in the nerve cell and how much is released. The VMAT2 inhibitors blocks VMAT2 which means there is a lower amount of neurotransmitter available and therefore reduces the unwanted body movements.

What they treat

VMAT2 inhibitors are used to treat specific conditions that have involuntary body movements like Huntington’s disease and tardive dyskinesia.

Side effects

VMAT2 inhibitors may have unwanted side effects which can depend on which type of VMAT2 inhibitor has been taken. These may include

• sleepiness
• dry mouth
• vision problems
• constipation
• heart conduction changes (change in QT interval)
• an increase risk of suicide.