Valbenazine

What is Valbenazine?

Valbenazine is a medication primarily used in the treatment of involuntary movements associated with tardive dyskinesia. It is an oral drug that belongs to a class of medications known as selective VMAT2 inhibitors. Tardive dyskinesia is a neurological condition characterized by repetitive, involuntary movements of the face, trunk, and extremities, often developing as a side effect of long-term use of certain antipsychotic medications. Valbenazine works by targeting specific pathways in the brain to help reduce the severity of these uncontrollable movements, offering a significant improvement in the quality of life for affected individuals. Approved for use in adults, Valbenazine represents an important therapeutic option for managing this challenging condition.

How Does it Work?

The mechanism of action of Valbenazine is centered around its role as a selective vesicular monoamine transporter 2 (VMAT2) inhibitor. VMAT2 is a protein responsible for packaging monoamines, such as dopamine, serotonin, and norepinephrine, into synaptic vesicles in neurons. By selectively inhibiting VMAT2, Valbenazine reduces the amount of dopamine released into the synaptic cleft. In the context of tardive dyskinesia, it is believed that an oversensitivity of dopamine receptors, often induced by long-term dopamine receptor blocking agents (like antipsychotics), contributes to the involuntary movements. By modulating dopamine levels, Valbenazine helps to rebalance dopaminergic activity in the brain, thereby decreasing the hyperkinetic movements characteristic of tardive dyskinesia. This selective action minimizes interference with other neurotransmitter systems, contributing to its favorable tolerability profile compared to older treatments for movement disorders.

Medical Uses

Treatment of Tardive Dyskinesia

The primary and most established medical use of Valbenazine is the treatment of tardive dyskinesia in adults. This condition can be highly debilitating, impacting speech, eating, and social interactions due to uncontrolled movements. Valbenazine has demonstrated significant efficacy in clinical trials, showing a substantial reduction in the abnormal involuntary movement scale (AIMS) scores, which are used to assess the severity of tardive dyskinesia. Its approval has provided a much-needed targeted treatment for patients who previously had limited options.

Potential for Other Hyperkinetic Movement Disorders

While primarily indicated for tardive dyskinesia, there is ongoing research and interest in the potential use of Valbenazine for other hyperkinetic movement disorders. For instance, some studies and clinical experience suggest its utility in managing Huntington's disease chorea, which also involves involuntary, jerky movements. However, for these conditions, it is crucial to consult with a specialist, as the indications and evidence base may differ from its established use in tardive dyskinesia.

Dosage

The dosage of Valbenazine must always be determined and supervised by a healthcare professional. It is typically administered orally once daily, with or without food. The starting dose for adults with tardive dyskinesia is usually 40 mg once daily. After one week, the dose may be increased to the recommended maintenance dose of 80 mg once daily, based on individual response and tolerability. Some patients may require a slower titration or a lower maintenance dose, especially those with hepatic impairment or those taking certain interacting medications. It is crucial not to adjust the dose without medical advice. Patients should be monitored for efficacy and side effects throughout treatment. If a dose is missed, it should be taken as soon as remembered unless it is almost time for the next dose, in which case the missed dose should be skipped.

Side Effects

Like all medications, Valbenazine can cause side effects, though not everyone experiences them. It is important to discuss any concerns with a healthcare provider. Common side effects may include:

• Somnolence (drowsiness)
• Anticholinergic effects (e.g., dry mouth, blurred vision, constipation)
• Insomnia
• Akathisia (restlessness)
• Headache
• Nausea
• Fatigue

More serious, though less common, side effects can occur and require immediate medical attention. These include:

• QT prolongation (a heart rhythm disorder)
• Neuroleptic Malignant Syndrome (NMS) (a rare but serious reaction)
• Parkinsonism (symptoms resembling Parkinson's disease, such as tremor and rigidity)
• Angioedema (swelling beneath the skin)

Patients should report any new or worsening symptoms to their doctor promptly.

Drug Interactions

Valbenazine is primarily metabolized by the CYP2D6 and CYP3A4 enzymes in the liver, meaning that other drugs affecting these enzymes can alter Valbenazine levels. Significant drug interactions include:

• Strong CYP3A4 Inhibitors: Co-administration with strong CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin) can increase Valbenazine exposure, potentially requiring a dose reduction of Valbenazine.
• Strong CYP2D6 Inhibitors: Co-administration with strong CYP2D6 inhibitors (e.g., paroxetine, fluoxetine, quinidine) can also increase Valbenazine exposure, necessitating careful monitoring and possibly a dose adjustment.
• Strong CYP3A4 Inducers: Co-administration with strong CYP3A4 inducers (e.g., rifampin, carbamazepine, St. John's Wort) can decrease Valbenazine exposure, potentially reducing its effectiveness.
• QT Prolonging Drugs: Caution is advised when Valbenazine is co-administered with other drugs known to prolong the QT interval, as this could increase the risk of serious heart rhythm abnormalities. Examples include certain antiarrhythmics, antipsychotics, and antibiotics.
• CNS Depressants: Concurrent use with other CNS depressants (e.g., alcohol, benzodiazepines, opioids) may enhance sedative effects.

It is crucial to inform your healthcare provider about all medications, supplements, and herbal products you are currently taking to avoid potential interactions.

FAQ

Q: What is tardive dyskinesia?

A: Tardive dyskinesia is a neurological condition characterized by involuntary, repetitive body movements. It most commonly affects the face, lips, tongue, and jaw, but can also involve the trunk and limbs. It often develops as a side effect of long-term use of certain medications, particularly older antipsychotics.

Q: How quickly does Valbenazine work?

A: Patients may start to see improvements in their tardive dyskinesia symptoms within a few weeks of starting Valbenazine treatment. Full therapeutic effects may take longer to manifest. Consistent daily dosing is important for optimal results.

Q: Can Valbenazine be stopped suddenly?

A: It is not recommended to stop Valbenazine suddenly without consulting a healthcare provider. While it is not known to cause withdrawal symptoms in the same way as some other medications, abrupt discontinuation could lead to a worsening of tardive dyskinesia symptoms. Any changes to your medication regimen should be medically supervised.

Q: Is Valbenazine addictive?

A: Valbenazine is not considered to be an addictive substance and does not typically lead to physical dependence or withdrawal symptoms associated with addiction. However, it is a prescription medication and should only be used as directed by a healthcare professional.

Products containing Valbenazine are available through trusted online pharmacies. You can browse Valbenazine-based medications at ShipperVIP or Medicenter.

Summary

Valbenazine is an important therapeutic option for adults suffering from tardive dyskinesia, a challenging neurological condition marked by involuntary movements. As a selective VMAT2 inhibitor, it works by modulating dopamine release in the brain, helping to reduce the severity of these uncontrollable movements. While generally well-tolerated, potential side effects and drug interactions exist, emphasizing the importance of medical supervision for dosage and ongoing monitoring. For individuals managing tardive dyskinesia, Valbenazine offers a targeted approach to improving motor control and overall quality of life, representing a significant advancement in the treatment of movement disorders.