Tetrabez 12.5 Tablet

Generic Name: Tetrabenazine

Strength: 12.5 mg

Presentation: Pale brown, round-shaped tablets.

Manufacturer: Unimed Unihealth Pharmaceuticals Ltd.

Therapeutic Class: Atypical neuroleptic drug.

Indications:

• Treatment of chorea associated with Huntington's disease.

Pharmacology:

• Tetrabenazine is a reversible inhibitor of the human vesicular monoamine transporter type 2 (VMAT2).

• It works within the basal ganglia to promote depletion of monoamine neurotransmitters (dopamine, serotonin, norepinephrine) from their storage sites and decreases their uptake into synaptic vesicles.

• Dopamine is required for fine motor movement, so inhibiting its transmission helps control hyperkinetic movement.

Dosage and Administration:

• The dose is individualized and titrated gradually.

• Adults:

  • Initial dose: 12.5 mg once daily in the morning.

  • After one week: Increase to 12.5 mg twice daily.

  • Increase at weekly intervals by 12.5 mg daily to find a tolerated and effective dose.

  • Doses of 37.5 to 50 mg/day should be given in three divided doses.

  • Maximum single dose: 25 mg.

  • Maximum daily dose: 100 mg.

• May be taken with or without food.

Contraindications:

• Hypersensitivity to tetrabenazine.

• Active suicidal ideation or untreated/inadequately treated depression.

• Hepatic impairment.

• Concurrent use of monoamine oxidase inhibitors (MAOIs), reserpine, deutetrabenazine, or valbenazine.

• Breastfeeding.

Warnings and Precautions:

• Depression and Suicidality: Tetrabenazine can increase the risk of depression and suicidal thoughts. Monitor patients for new or worsening depression, suicidal thoughts, or unusual behavior changes.

• QTc Prolongation: Tetrabenazine may prolong the QTc interval. Avoid use with other drugs that prolong QTc.

• Neuroleptic Malignant Syndrome (NMS): A rare but potentially fatal condition characterized by fever, muscle rigidity, altered mental status, and autonomic dysfunction. Discontinue Tetrabenazine if NMS is suspected.

• Parkinsonism: Tetrabenazine may exacerbate symptoms of parkinsonism.

• Tardive Dyskinesia: Tetrabenazine may increase the risk of tardive dyskinesia, a syndrome of potentially irreversible, involuntary, dyskinetic movements.

• Drug Interactions:

  • Strong CYP2D6 inhibitors: May require a reduction in Tetrabenazine dose.

  • Reserpine: Do not use together; allow at least 20 days after stopping reserpine before starting Tetrabenazine.

  • Alcohol and other sedating drugs: May increase drowsiness.

• Hepatic Impairment: Contraindicated in hepatic impairment.

• Renal Impairment: Use with caution; dose adjustment may be needed.

• Pregnancy: Tetrabenazine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

• Lactation: Contraindicated during breastfeeding.

• Driving and Operating Machinery: Tetrabenazine may cause drowsiness, and caution should be exercised.

Common Side Effects: