What are the appropriate indications, dosing regimen, contraindications, and monitoring recommendations for Austedo (dextromethorphan/quinidine) in adults?

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Last updated: October 16, 2026 • View editorial policy

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Austedo (Deutetrabenazine) Clinical Guide

Primary Indications

Austedo is FDA-approved for two specific indications in adults: chorea associated with Huntington's disease and tardive dyskinesia. 1 These are the only evidence-based uses supported by clinical trials and regulatory approval.

Critical Contraindications

Absolute contraindications include: 1

  • Suicidal ideation or behavior
  • Untreated or inadequately treated depression (particularly in Huntington's disease patients)
  • Hepatic impairment of any degree
  • Concurrent use of reserpine, MAOIs, tetrabenazine, or valbenazine

Boxed Warning for Depression and Suicidality

Austedo carries a black box warning specifically for Huntington's disease patients due to increased risk of depression and suicidal thoughts. Exercise extreme caution in patients with prior suicide attempts or depression history. 1

Dosing Regimen

Standard Formulations Available:

  • AUSTEDO XR (extended-release): Once-daily dosing
  • AUSTEDO (immediate-release): Twice-daily dosing

Initial Dosing:

Formulation Starting Dose Administration
AUSTEDO XR 12 mg once daily With or without food; swallow whole
AUSTEDO 6 mg twice daily (12 mg/day total) With food; swallow whole

Titration Protocol:

  • Increase by 6 mg per day at weekly intervals based on symptom reduction and tolerability
  • Maximum dose: 48 mg per day for both formulations 1
  • Titrate to the lowest effective dose that controls symptoms

Special Population Dosing:

CYP2D6 Poor Metabolizers or Patients on Strong CYP2D6 Inhibitors:

  • Maximum dose: 36 mg per day (not 48 mg) 1
  • This is a critical safety consideration to prevent excessive drug accumulation

Switching from Tetrabenazine:

Discontinue tetrabenazine and start Austedo the following day using equivalent dosing (see conversion table in prescribing information). 1

Key Warnings and Monitoring

QT Prolongation Risk:

  • Avoid in patients with congenital long QT syndrome or arrhythmias 1
  • Consider baseline and periodic ECG monitoring, especially with other QT-prolonging medications

Neuroleptic Malignant Syndrome (NMS):

  • Discontinue immediately if suspected 1
  • Monitor for hyperthermia, muscle rigidity, altered mental status, autonomic instability

Movement Disorders:

  • Akathisia, parkinsonism, and restlessness may occur 1
  • Reduce dose or discontinue if these emerge
  • Paradoxically, the drug treats one movement disorder but can cause others

Sedation and Somnolence:

  • May impair driving and operating machinery 1
  • Warn patients about additive effects with alcohol and other CNS depressants

Depression Monitoring:

  • Closely monitor for emergence or worsening of depression, suicidality, or behavioral changes 1
  • Educate patients, caregivers, and families to report concerning behaviors immediately
  • This is particularly critical in Huntington's disease patients

Critical Drug Interactions

Strong CYP2D6 Inhibitors (paroxetine, fluoxetine, bupropion, quinidine):

  • Limit Austedo to maximum 36 mg/day 1

Avoid Concurrent Use With:

  • Reserpine (wait 20 days after reserpine before starting Austedo)
  • MAOIs (wait 14 days)
  • Other VMAT2 inhibitors (tetrabenazine, valbenazine) 1

Use Caution With:

  • Alcohol and sedating medications (additive CNS depression) 1
  • QT-prolonging drugs

Discontinuation

Austedo can be stopped abruptly without tapering. 1 However:

  • If interrupted >1 week: Re-titrate from starting dose
  • If interrupted <1 week: Resume previous maintenance dose

Important Clinical Context

Off-Label Use Concerns:

The 2019 AGS Beers Criteria specifically cautions against dextromethorphan/quinidine (a different combination drug) in older adults with dementia-related behavioral symptoms due to limited efficacy and increased fall risk. 2 While this refers to a different formulation, the principle of caution in elderly patients with dementia applies.

Real-world data shows Austedo is frequently prescribed off-label for dementia and Parkinson's disease patients (57% of prescriptions), despite FDA approval only for Huntington's chorea and tardive dyskinesia. 3 This off-label use lacks robust evidence and carries significant safety concerns, particularly given the contraindication in hepatic impairment and risks in elderly populations.

Most Common Adverse Events:

  • In Huntington's disease: Somnolence, diarrhea, dry mouth, fatigue (>8% incidence) 1
  • In tardive dyskinesia: Nasopharyngitis, insomnia (>4% incidence) 1

Clinical Pitfalls to Avoid

  1. Do not prescribe to patients with any degree of hepatic impairment - this is an absolute contraindication
  2. Do not exceed 36 mg/day in CYP2D6 poor metabolizers - genetic testing may be warranted in some cases
  3. Do not use in actively suicidal or severely depressed Huntington's patients without psychiatric stabilization first
  4. Do not crush, chew, or break tablets - must be swallowed whole for proper pharmacokinetics
  5. Do not forget to administer immediate-release AUSTEDO with food when total daily dose ≥12 mg

References

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This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.