What the FDA labels say about taking them together
Quinidine and trazodone
Trazodone's FDA label of January 22, 2026 names quinidine in its drug interactions section; the quinidine label PlainMeds reads does not name trazodone. The trazodone label: “The use of trazodone should be avoided in patients with known QT prolongation or in combination with other drugs that are inhibitors of CYP3A4, or known to prolong QT interval including Class 1A antiarrhythmics or Class …”
Check it at the source: the quinidine FDA label on DailyMed (effective February 1, 2018, Sun Pharmaceutical Industries, Inc.); the trazodone FDA label on DailyMed (effective January 22, 2026, Zydus Pharmaceuticals USA Inc.).
What does the quinidine label say about trazodone?
Quinidine's label (effective February 1, 2018) does not name trazodone in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Quinidine Gluconate), Sun Pharmaceutical Industries, Inc., effective February 1, 2018 (SPL set 5023f053-fcc4-4c2c-aa59-9ec198ad185e), via openFDA; the full label on DailyMed
What does the trazodone label say about quinidine?
Trazodone label, drug interactionsExamples; Class 1A antiarrhythmics: quinidine, procainamide, disopyramide; Class 3 antiarrhythmics: amiodarone, sotalol; Antipsychotics: ziprasidone, chlorpromazine, thioridazine; Antibiotics: gatifloxacin
Trazodone label, warnings and precautionsThe use of trazodone should be avoided in patients with known QT prolongation or in combination with other drugs that are inhibitors of CYP3A4 (e.g., itraconazole, clarithromycin, voriconazole), or known to prolong QT interval including Class 1A antiarrhythmics (e.g., quinidine, procainamide) or Class 3 antiarrhythmics (e.g., amiodarone, sotalol), certain antipsychotic medications (e.g., ziprasidone, chlorpromazine, thioridazine), and certain antibiotics (e.g., gatifloxacin).
Source: FDA drug label (Raldesy Tm, NDA218637), Validus Pharmaceuticals LLC, effective September 1, 2026 (SPL set 34708cc1-b0b2-4fd0-b9f3-7f008b457fc9), via openFDA
Source: FDA drug label (Trazodone Hydrochloride), Zydus Pharmaceuticals USA Inc., effective January 22, 2026 (SPL set 704aebf9-2fff-4ef3-8323-9ff0d7f0ffd9), 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
| Quinidine | Trazodone | |
|---|---|---|
| Labeled for | Atrial fibrillation | Depression |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $4.92 per tablet 324 mg tablet | $0.0307 per tablet 50 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