Chlorpromazine and Tetrabenazine Interaction

Drug interaction information between Chlorpromazine and Tetrabenazine.

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

FDA drug labeling documents a moderate-severity interaction between Chlorpromazine and Tetrabenazine. 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

Chlorpromazine

Typical Antipsychotic (Phenothiazine)

Drug B

Tetrabenazine

VMAT2 Inhibitor

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 Chlorpromazine + Tetrabenazine?

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: Chlorpromazine has 4 (also Desmopressin, Tranylcypromine, Zolpidem); Tetrabenazine has 9 (also Olanzapine, Risperidone, Ziprasidone, Haloperidol).

What mechanism field is on file for Chlorpromazine and Tetrabenazine?

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: Chlorpromazine (Typical Antipsychotic (Phenothiazine)); Tetrabenazine (VMAT2 Inhibitor).

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

Chlorpromazine

0 major · 4 moderate · 7 minor · 11 total

Tetrabenazine

2 major · 9 moderate · 5 minor · 16 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.