Deutetrabenazine and Quinidine: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Deutetrabenazine
Quinidine
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Increased deutetrabenazine exposure; prolongation of QT interval
Interaction Deep Dive
Avoid coadministration of deutetrabenazine (a CYP2D6 substrate and drug known to prolong the QT interval) with agents that are strong CYP2D6 inhibitors and also prolong the QT interval, due to an increase in deutetrabenazine exposure and an increased risk of torsade de pointes and/or sudden death. Concomitant use of strong CYP2D6 inhibitors has increased the systemic exposure of the active deutetrabenazine metabolites by about 3-fold. If coadministered, a reduction in deutetrabenazine dose may be necessary when adding a strong CYP2D6 inhibitor in patients maintained on a stable dose of deutetrabenazine. The dose of deutetrabenazine should not exceed 36 mg/day, and the maximum single dose should not exceed 18 mg1.
Why it happens (mechanism)
Inhibition of CYP2D6-mediated deutetrabenazine metabolism; additive effects on QT interval
Literature reports
1 report — tap to read
a) Coadministration of a single 22.5-mg dose of deutetrabenazine to 24 healthy subjects who received 8 days of paroxetine 20 mg daily (a strong CYP2D6 inhibitor) resulted in an increase in the AUC(infinity) of the active deutetrabenazine metabolites, alpha-HTBZ and beta-HTBZ of 1.9-fold and 6.5-fold, and an increase in Cmax of 1.2-fold and 2.2-fold. The total (alpha plus beta)-HTBZ AUC(infinity) increased about 3-fold. Additionally, the clearance of these metabolites was decreased, resulting in increases in mean t(1/2) of approximately 1.5-fold and 2.7-fold 1.
Common questions
Can I take Deutetrabenazine and Quinidine together?
Increased deutetrabenazine exposure; prolongation of QT interval Always confirm with your pharmacist or prescriber before making any change.
How serious is the Deutetrabenazine and Quinidine interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Deutetrabenazine or Quinidine need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (1)
- Product Information: AUSTEDO(TM) oral tablets, deutetrabenazine oral tablets. Teva Pharmaceuticals USA Inc (per FDA), North Wales, PA, 2017. DailyMed
Keep reading about Deutetrabenazine
Keep reading about Quinidine
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