Ajuben6 mg

Ajuben is a vesicular monoamine transporter 2 (VMAT2) inhibitor approved for use in adults for the following FDA-approved (established) indications:

• Chorea associated with Huntington's disease — reduces involuntary, dance-like movements.
• Tardive dyskinesia — reduces repetitive, involuntary movements (typically of the face, tongue, or limbs) caused by long-term use of dopamine-receptor-blocking drugs such as antipsychotics.

Ajuben has also been studied in small clinical trials for other hyperkinetic movement disorders (for example, tic disorders such as Tourette syndrome); this is considered off-label use and is not an FDA-approved indication, so it should only be considered under specialist supervision.

Ajuben does not cure the underlying disease; it manages the movement symptoms.

Each tablet contains Deutetrabenazine as the active ingredient. Deutetrabenazine is available as immediate-release tablets (commonly 6 mg, 9 mg, and 12 mg) and as extended-release tablets (commonly 6 mg, 12 mg, and 24 mg), along with standard pharmaceutical excipients such as microcrystalline cellulose, colloidal silicon dioxide, magnesium stearate, and a film-coating agent.

Ajuben is a deuterium-substituted analog of tetrabenazine that works by reversibly inhibiting the vesicular monoamine transporter 2 (VMAT2). By replacing certain hydrogen atoms with deuterium, Ajuben is metabolized more slowly than tetrabenazine, producing more stable blood levels and allowing less frequent dosing with a lower burden of dose-related side effects at equivalent efficacy.

Ajuben is used to control abnormal involuntary movements — specifically chorea in Huntington's disease and dyskinetic movements caused by antipsychotic medicines (tardive dyskinesia). It does not treat the underlying neurological or psychiatric disease.

Vesicular Monoamine Transporter 2 (VMAT2) Inhibitor — Anti-chorea / Anti-dyskinetic agent (active ingredient: Ajuben)

Mechanism

Deutetrabenazine reversibly inhibits VMAT2, the transporter responsible for packaging dopamine, serotonin, norepinephrine, and histamine into presynaptic vesicles for release. By reducing VMAT2 activity, Deutetrabenazine depletes presynaptic stores of monoamines — particularly dopamine — in the striatum, which reduces the excessive dopaminergic signaling that underlies chorea and tardive dyskinesia.

Pharmacokinetics

Deutetrabenazine is rapidly metabolized by carbonyl reductase to its active metabolites (alpha- and beta-dihydrotetrabenazine), which are further metabolized mainly by the CYP2D6 enzyme. Deuterium substitution slows this metabolism relative to tetrabenazine, extending the half-life of the active metabolites and reducing peak-to-trough fluctuations. Elimination is predominantly renal (as metabolites), with a smaller fecal component.

Take Ajuben exactly as prescribed, with food. Swallow extended-release tablets whole — do not crush, chew, or split them. Immediate-release tablets may be taken in divided doses per the physician's directions. Do not change the dose or stop treatment suddenly without consulting the prescribing physician.

Ajuben has clinically important interactions with the following:

• Monoamine oxidase inhibitors (MAOIs): Contraindicated; do not use Ajuben within 14 days of stopping an MAOI, and vice versa.
• Reserpine: Contraindicated concurrently, and for at least 20 days after stopping reserpine, due to risk of excessive monoamine depletion and neuroleptic malignant syndrome.
• Other VMAT2 inhibitors (tetrabenazine, valbenazine): Should not be used together with Ajuben — see Contraindications.
• Strong CYP2D6 inhibitors (e.g., paroxetine, fluoxetine, bupropion): Increase exposure to active Ajuben metabolites; the maximum daily dose of Ajuben must be reduced (typically capped at 36 mg/day) and titrated more cautiously.
• Digoxin: Ajuben may increase digoxin plasma levels via P-glycoprotein effects; digoxin levels should be monitored if used together.
• Dopamine receptor-blocking drugs / antipsychotics: Additive risk of parkinsonism, akathisia, and neuroleptic malignant syndrome.
• Alcohol and other CNS depressants (sedatives, opioids, benzodiazepines): Additive sedation; avoid or use with caution.
• Other QT-prolonging drugs: Additive risk of QT prolongation, particularly at higher Ajuben doses — see Precautions.

Common side effects of Ajuben include somnolence/drowsiness, diarrhea, dry mouth, fatigue, insomnia, and nasopharyngitis (common cold-type symptoms).

Serious side effects (require prompt medical attention) include:

• New or worsening depression, or suicidal thoughts/behavior (boxed warning in Huntington's disease patients — see Precautions).
• Parkinsonism (slowness, rigidity, tremor) and akathisia (inner restlessness), which are dose-related.
• Neuroleptic malignant syndrome (rare but potentially life-threatening — fever, muscle rigidity, altered consciousness, autonomic instability), especially with concurrent dopamine-blocking drugs.
• QT interval prolongation at higher doses, which can predispose to serious irregular heart rhythms.
• Sedation severe enough to impair driving or operating machinery.

Pregnancy: Animal reproduction studies with Ajuben have shown evidence of fetal harm at doses relevant to human exposure, and adequate, well-controlled studies in pregnant women are lacking. Ajuben should be used during pregnancy only if clearly needed and if the potential benefit to the mother justifies the potential risk to the fetus. A physician should always be consulted before use in pregnancy.

Lactation: It is not known whether Ajuben or its metabolites pass into human breast milk. Because of the potential for adverse effects in a nursing infant, a decision should be made, in consultation with a physician, whether to discontinue breastfeeding or discontinue Ajuben, weighing the importance of treatment to the mother.

Boxed Warning: Depression and Suicidal Ideation

In patients with Huntington's disease, Ajuben can increase the risk of depression and suicidal thoughts and behavior (suicidality). Patients, caregivers, and families should be alert for new or worsening depression, agitation, irritability, or suicidal thoughts, and should report these immediately to the treating physician. Ajuben should be contraindicated in Huntington's disease patients who are actively suicidal or have untreated/inadequately treated depression, and used only after balancing the benefit of chorea control against this risk in others (see Contraindications).

Other precautions

• Parkinsonism and akathisia: Dose-related; may require dose reduction if symptoms are troublesome.
• Sedation/somnolence: May impair the ability to drive or operate machinery; caution with alcohol or other sedating medicines.
• Neuroleptic malignant syndrome (NMS): A rare but serious risk, particularly with concurrent dopamine-blocking drugs; discontinue immediately if suspected and seek emergency care.
• QT interval prolongation: Dose-dependent; use caution in patients with risk factors for QT prolongation, and consider ECG monitoring in at-risk patients, especially at higher doses or with other QT-prolonging drugs.
• Hepatic impairment: Contraindicated (see Contraindications) because metabolite clearance is significantly reduced.

Overdose with Ajuben may cause acute dystonia, oculogyric crisis, sedation, hypotension, confusion, tremor, nausea/vomiting, and worsening of the underlying movement disorder or its psychiatric features. There is no specific antidote; management is supportive, with close monitoring of vital signs, cardiac rhythm (ECG), and mental status.

If an overdose is suspected, seek immediate medical attention or contact emergency services / a poison control center right away. Do not attempt to treat an overdose at home.

Store at room temperature (below 30°C), away from light and moisture. Keep out of reach of children.

• Hepatic impairment: Contraindicated — Ajuben should not be used in any patient with hepatic impairment (see Contraindications).
• Renal impairment: No formal dose adjustment is established; use with caution and physician monitoring, as data in severe renal impairment are limited.
• CYP2D6 poor metabolizers / strong CYP2D6 inhibitor use: Maximum daily dose is capped (commonly 36 mg/day) and titration should be more gradual — see Interactions.
• Elderly: Limited clinical data; use with caution, starting at the lower end of the dosing range, with attention to sedation and cardiac risk.
• Pediatric patients: Safety and efficacy have not been established in patients under 18 years of age (see Pediatric Uses).
• Cardiac disease / QT risk factors: Use with caution and ECG monitoring where appropriate, particularly at higher doses.

Ajuben is generally used long-term/chronically for as long as it continues to provide meaningful control of chorea or dyskinesia with acceptable tolerability. For tardive dyskinesia in particular, physicians periodically reassess the ongoing need for treatment (for example, by considering a brief dose reduction or trial discontinuation), because dyskinesia may improve over time or with adjustment of the underlying antipsychotic regimen. Any change in duration or discontinuation should be directed by the treating physician, since stopping abruptly can cause symptoms to re-emerge or worsen.

VMAT2 (vesicular monoamine transporter 2) inhibitors — the class that also includes tetrabenazine and valbenazine; Deutetrabenazine is a deuterated analog of tetrabenazine.

Deutetrabenazine reversibly binds to and inhibits VMAT2, the transporter that loads dopamine and other monoamines into presynaptic storage vesicles. This reduces the amount of dopamine available for release into the synapse, which in turn dampens the excessive dopaminergic transmission responsible for chorea (in Huntington's disease) and tardive dyskinesia (from long-term dopamine-receptor-blocking drug use).

The safety and efficacy of Ajuben have not been established in pediatric patients (under 18 years of age) for either chorea associated with Huntington's disease or tardive dyskinesia. Ajuben is therefore not recommended for use in children or adolescents outside of a clinical trial setting, and should only be considered in this age group under close specialist supervision if no alternative exists.