What Ingrezza Treats and How It Works
Ingrezza (valbenazine) is approved to treat tardive dyskinesia, a condition causing involuntary movements like lip smacking, tongue protrusion, or rapid eye blinking, often from long-term antipsychotic use. It blocks VMAT2 in the brain to reduce excess dopamine signaling that triggers these movements.[1]
Common Involuntary Movements Reported with Ingrezza
Ingrezza's main purpose is to decrease involuntary movements, but some patients experience new or worsened ones. Clinical trials and post-marketing data show:
- Choreiform movements: Jerky, dance-like motions in limbs or torso, affecting up to 2% of users.[2]
- Tremor or shaking: Fine or coarse involuntary shaking, sometimes in hands or head.[1][2]
- Myoclonus: Sudden, brief muscle jerks, reported in isolated cases.[3]
- Akathisia: Inner restlessness with fidgeting or pacing, though less common than with other VMAT2 inhibitors.[2]
These occur in 1-3% of patients, typically early in treatment, and often resolve with dose adjustment or discontinuation.[1]
Why Do These Movements Happen?
Ingrezza reduces striatal dopamine too aggressively in some people, disrupting motor control balance. Risk rises with higher doses (80 mg vs. 40 mg), concurrent antipsychotics, or conditions like Parkinson's.[2][4]
How Often Do They Occur Compared to Placebo?
In pivotal trials (KINECT studies):
| Movement Type | Ingrezza (40-80 mg) | Placebo |
|---------------|---------------------|---------|
| Any dyskinesia | 2.1% | 1.0% |
| Choreoathetosis | 1.3% | 0.5% |
| Tremor | 0.8% | 0% |
Differences were not always statistically significant, but monitoring is advised.[2]
What Should Patients Do If Movements Appear?
Report to a doctor immediately—most cases improve within weeks of stopping or lowering the dose. Do not abruptly quit without guidance, as rebound TD can worsen.[1][4]
Differences from Other VMAT2 Drugs Like Austedo
Ingrezza has a lower akathisia risk (0.5-1%) than Austedo (deutetrabenazine, up to 10%), but similar chorea rates. Switching may help if movements persist.[3][5]
[1]: Ingrezza Prescribing Information (FDA)
[2]: KINECT 3 Trial Data (NEJM, 2022)
[3]: Drugs.com Ingrezza Side Effects
[4]: Neurocrine Biosciences Safety Profile
[5]: Austedo vs. Ingrezza Comparison (Medscape)