What the FDA labels say about taking them together
Procainamide and tetrabenazine
Tetrabenazine's FDA label of November 29, 2019 names procainamide in its drug interactions section; the procainamide label PlainMeds reads does not name tetrabenazine.
Check it at the source: the procainamide FDA label on DailyMed (effective February 17, 2025, Caplin Steriles Limited); the tetrabenazine FDA label on DailyMed (effective November 29, 2019, Oceanside Pharmaceuticals).
What does the procainamide label say about tetrabenazine?
Procainamide's label (effective February 17, 2025) does not name tetrabenazine in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Procainamide Hydrochloride), Caplin Steriles Limited, effective February 17, 2025 (SPL set fcaa5e9a-3c8a-4796-aa87-626268b6cf60), via openFDA; the full label on DailyMed
What does the tetrabenazine label say about procainamide?
Tetrabenazine label, drug interactionsTetrabenazine tablets cause 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.
Tetrabenazine label, warnings and precautionsThe use of tetrabenazine tablets should be avoided in combination with other drugs that are known to prolong QTc, 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 [see Drug Interactions ( 7.5 )].
Source: FDA drug label (tetrabenazine), NDA021894 (Bausch), as published by Oceanside Pharmaceuticals, effective November 29, 2019 (SPL set 5867189c-17bd-4e70-a079-c4730f9950d1), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Procainamide | Tetrabenazine | |
|---|---|---|
| Labeled for | n/a | n/a |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | n/a | $0.702 per tablet 12.5 mg tablet |
| Shortage now | No current entry | No current entry |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once