What the FDA labels say about taking them together
Amitriptyline and quinidine
Amitriptyline's FDA label of September 8, 2026 names quinidine in its drug interactions section; the quinidine label PlainMeds reads does not name amitriptyline.
Check it at the source: the amitriptyline FDA label on DailyMed (effective September 8, 2026, Sun Pharmaceutical Industries, Inc.); the quinidine FDA label on DailyMed (effective February 1, 2018, Sun Pharmaceutical Industries, Inc.).
What does the amitriptyline label say about quinidine?
Amitriptyline label, drug interactionsThe drugs that inhibit cytochrome P450 2D6 include some that are not metabolized by the enzyme (quinidine; cimetidine) and many that are substrates for P450 2D6 (many other antidepressants, phenothiazines, and the Type 1C antiarrhythmics propafenone and flecainide).
Source: FDA drug label (Amitriptyline Hydrochloride), Sun Pharmaceutical Industries, Inc., effective September 8, 2026 (SPL set 4e520c63-1cf6-40f6-a51c-3f9b0e181342), via openFDA; the full label on DailyMed
What does the quinidine label say about amitriptyline?
Quinidine's label (effective February 1, 2018) does not name amitriptyline 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
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
| Amitriptyline | Quinidine | |
|---|---|---|
| Labeled for | Depression | Atrial fibrillation |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.03 per tablet 10 mg tablet | $4.92 per tablet 324 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