Tetrabenazine and Chlorpromazine Interaction

Drug interaction information between Tetrabenazine and Chlorpromazine.

Tetrabenazine and Chlorpromazine have a documented moderate interaction in FDA labeling.

FDA drug labeling documents a moderate-severity interaction between Tetrabenazine and Chlorpromazine. This page displays the available source-record category and label text. The category is not an individual risk estimate or medication-combination direction.

Drug A

Tetrabenazine

VMAT2 Inhibitor

Drug B

Chlorpromazine

Typical Antipsychotic (Phenothiazine)

How They Interact

These drugs can work together to slow the heart's electrical timing and cause movement-related side effects.

FDA Label Information

7.5 Drugs That Cause QTc Prolongation Tetrabenazine causes a small prolongation of QTc (about 8 msec), concomitant use with other drugs that are known to cause QTc prolongation should be avoided, these including antipsychotic medications (e.g., chlorpromazine, haloperidol, thioridazine, ziprasidone), antibiotics (e.g., moxifloxacin), Class 1A (e.g., quinidine, procainamide) and Class III (e.g., amiodarone, sotalol) antiarrhythmic medications or any other medications known to prolong the QTc interval. 7.6 Neuroleptic Drugs The risk for Parkinsonism, NMS, and akathisia may be increased by...

Frequently Asked Questions

What SPL severity band is on file for Tetrabenazine + Chlorpromazine?

Compiled FDA labeling labels this pair moderate. That is a source-record field, not an individual medication-combination decision.

Which drug in this pair has the larger labeled-interaction portfolio?

Tetrabenazine has 16 labeled pairs on file vs Chlorpromazine's 11. In the moderate band specifically: Tetrabenazine has 9 (also Olanzapine, Risperidone, Ziprasidone, Haloperidol); Chlorpromazine has 4 (also Desmopressin, Tranylcypromine, Zolpidem).

What mechanism field is on file for Tetrabenazine and Chlorpromazine?

These drugs can work together to slow the heart's electrical timing and cause movement-related side effects.

Tetrabenazine carries more major-labeled pairs than Chlorpromazine

SPL source-record counts only. This page's band is moderate · classes on file: Tetrabenazine (VMAT2 Inhibitor); Chlorpromazine (Typical Antipsychotic (Phenothiazine)).

Tetrabenazine has 2 major-labeled pairs vs Chlorpromazine's 0. This page itself is in the moderate band, not the major band.

Tetrabenazine

2 major · 9 moderate · 5 minor · 16 total

Chlorpromazine

0 major · 4 moderate · 7 minor · 11 total

Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. This registry does not provide individual medication-combination directions.