Home Drug Guide Tetrabenazine

Drug Guide

Generic Name

Tetrabenazine

Brand Names Xenazine

Classification

Therapeutic: Antipsychotic, movement disorder agent

Pharmacological: Vesicular Monoamine Transporter 2 (VMAT2) inhibitor

FDA Approved Indications

  • Huntington's disease chorea

Mechanism of Action

Tetrabenazine depletes dopamine, serotonin, norepinephrine, and histamine by inhibiting VMAT2, leading to decreased monoamine storage in presynaptic neurons, reducing excessive movement in chorea.

Dosage and Administration

Adult: Initial dose typically 12.5 mg once or twice daily; titrate gradually based on response and tolerability. Maintenance dose usually 50 mg/day in divided doses, up to a maximum of 100 mg/day.

Pediatric: Not approved for pediatric use.

Geriatric: Start at lower doses and titrate carefully due to increased sensitivity and risk of side effects.

Renal Impairment: Use with caution; no specific dose adjustments established.

Hepatic Impairment: Use contraindicated in severe hepatic impairment.

Pharmacokinetics

Absorption: Well absorbed orally.

Distribution: Widely distributed; crosses blood-brain barrier.

Metabolism: Primarily via hepatic aldehyde oxidase and cytochrome P450 enzymes.

Excretion: Metabolites excreted mainly in urine.

Half Life: Approximately 4-8 hours.

Contraindications

  • Depression or history of suicidality
  • Use concomitantly with reserpine or monoamine oxidase inhibitors (MAOIs).

Precautions

  • Monitor for depression, suicidality, or worsening Parkinsonian symptoms. Use with caution in patients with cardiac or psychiatric comorbidities.

Adverse Reactions - Common

  • Hypotension (Common)
  • Sedation/drowsiness (Common)
  • Parkinsonism or other movement disorders (Common)
  • Somnolence (Common)
  • Decreased blood cell counts (e.g., akathisia, depression) (Uncommon)

Adverse Reactions - Serious

  • Suicidal thoughts or behavior (Rare)
  • Neuroleptic malignant syndrome (Rare)
  • Hepatotoxicity (Rare)

Drug-Drug Interactions

  • Antidepressants (risk of neuroleptic malignant syndrome)
  • Reserpine and other centrally acting dopamine-depleting agents
  • MAOIs (risk of hypertensive crisis)

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor mood, suicidal ideation, movement symptoms, blood pressure, and CBC regularly.

Diagnoses:

  • Risk for suicidal behavior
  • Ineffective coping related to movement disorder or side effects

Implementation: Start at low dose, titrate carefully, monitor for adverse effects, especially depression and movement changes.

Evaluation: Assess symptom control and side effects; adjust dose accordingly.

Patient/Family Teaching

  • Do not stop medication abruptly.
  • Report any mood changes, suicidal thoughts, or worsening symptoms.
  • Monitor blood pressure regularly.
  • Avoid alcohol and other CNS depressants.

Special Considerations

Black Box Warnings:

  • Increased risk of depression and suicidality.
  • Use caution in patients with a history of depression.

Genetic Factors: Genetic variations may influence metabolism and response.

Lab Test Interference: May cause false-positive results in urine catecholamine tests.

Overdose Management

Signs/Symptoms: Drowsiness, sedation, hypotension, extrapyramidal symptoms.

Treatment: Supportive care, monitoring vital signs, and symptomatic treatment. No specific antidote.

Storage and Handling

Storage: Store at room temperature, away from moisture and light.

Stability: Stable under proper storage conditions.

🛡️ 5 Critical Medication Safety Tips for Nurses

1

Triple-Check High-Risk Medications

Always have another nurse verify insulin, heparin, warfarin, and chemotherapy drugs. These "high-alert" medications cause the most serious errors. Check concentration, dose calculation, and pump settings twice.

2

Know Look-Alike, Sound-Alike Drugs

Common mix-ups: hydromorphone/morphine, Celebrex/Celexa, Zyprexa/Zyrtec. Always use BOTH generic and brand names, read labels twice, and use barcode scanning when available. One wrong letter can be fatal.

3

Assess Before AND After Giving Meds

Check vitals before cardiac meds, pain levels before analgesics, and blood glucose before insulin. Always reassess within 30 minutes to evaluate effectiveness and watch for adverse reactions.

4

Watch for Drug Interactions

Common dangerous combinations: warfarin + aspirin (bleeding), ACE inhibitors + potassium (hyperkalemia), digoxin + diuretics (toxicity). Always check drug interactions before administering new medications.

5

Educate Your Patients

Teach patients medication names, purposes, major side effects, and what to report. Informed patients catch errors and improve compliance. Always encourage questions - an educated patient is a safer patient.

⚡ Remember: When in doubt, don't give it out! It's always safer to double-check than regret later.

⚠️ Medical Disclaimer

This drug guide is for educational purposes only and is NOT intended for clinical use. Always consult current prescribing information, healthcare providers, and institutional protocols before administering any medication. Do not use this information for patient care decisions.