Generic
Tetrabenazine
12 brands available in the market
At a glance
Tetrabenazine is a VMAT2 inhibitor used for the treatment of chorea associated with Huntington's disease. It reduces involuntary movements by depleting monoamine stores in synaptic vesicles.
Description
Tetrabenazine is a vesicular monoamine transporter type 2 (VMAT2) inhibitor. It reduces uptake of dopamine, serotonin, norepinephrine, and histamine into synaptic vesicles, depleting monoamine stores from nerve terminals. It is similar to reserpine but with less peripheral activity and shorter-acting.
Indications
- Chorea associated with Huntington's disease
Therapeutic class
Atypical Neuroleptic Drugs
Pharmacological class
VMAT2 Inhibitor
Pharmacology
Tetrabenazine reversibly inhibits VMAT2 in synaptic vesicles, reducing uptake of dopamine, serotonin, norepinephrine, and histamine, depleting monoamine stores from nerve terminals and controlling hyperkinetic movements.
Mechanism of action
Reduces involuntary movements by depleting monoamine stores in synaptic vesicles.
Dosage
Adult Dose (Oral):
- Start (Week 1): 12.5 mg/day
- Week 2: 25 mg/day (12.5 mg twice daily)
- Titrate by 12.5 mg weekly to tolerated dose
- 37.5-50 mg/day: 3 divided doses (max single dose 25 mg)
- >50 mg/day: CYP2D6 genotyping required; Poor metabolizers: max 50 mg/day (single 25 mg); Extensive/intermediate: max 100 mg/day (single 37.5 mg)
- Elderly: Start 12.5 mg/day, increase gradually
Administration
- Can be taken with or without food
- Swallow tablet whole; do not chew, crush, or break
- Take at the same time each day
Missed dose
If you miss a dose, take it as soon as you remember; if almost time for the next dose, skip it; do not double the dose.
Side effects
Common Side Effects (>10%):
- Sedation/somnolence, fatigue
- Insomnia, depression
- Akathisia, anxiety
- Nausea
Serious (Rare):
- Neuroleptic malignant syndrome (fever, muscle rigidity, confusion)
- Suicidal thoughts
- Pneumonia
Precautions & warnings
- Do not use in hepatic impairment
- Do not use in actively suicidal or untreated/undertreated depression
- May affect driving ability (somnolence, dizziness)
- Do not stop abruptly (may worsen symptoms)
Contraindications
- Hypersensitivity
- Lactation
- Hepatic impairment
- Actively suicidal or untreated/undertreated depression
Drug interactions
- Strong CYP2D6 inhibitors (fluoxetine, paroxetine, quinidine): Tetrabenazine dose reduction may be needed
- MAOIs: Do not use concurrently or within 14 days of discontinuation
- Reserpine: Irreversible binding; 20-day washout required
- Levodopa: Decreased effects and worsened parkinsonism
- Amantadine, metoclopramide, antipsychotics: Increased extrapyramidal side effect risk
Food interactions
Alcohol is unsafe with Tetrabenazine (excessive drowsiness).
Use in pregnancy
Use in Pregnancy: May be unsafe; animal studies show harmful effects; use only if clearly needed; consult your doctor.
Pregnancy Category: D — always consult a doctor before taking during pregnancy.
Use in lactation
Use in Lactation: Probably unsafe; limited data suggests drug may pass into breast milk and harm the baby; consult your doctor.
Pediatric use
Safety and efficacy not established in children
Geriatric use
Pharmacokinetics not formally studied in geriatric subjects; start 12.5 mg/day
Renal / hepatic impairment
Renal Impairment: Limited information; caution needed; consult your doctor.
Hepatic Impairment: Unsafe; do not use; consult your doctor.
Overdose effects
Overdose may cause drowsiness, sweating, and hypothermia; provide symptomatic treatment.
Storage conditions
Store in a cool and dry place, protected from light and moisture; keep out of reach of children.
Chemical structure
Tetrabenazine