What the FDA labels say about taking them together
Donepezil/memantine and quinidine
Donepezil/memantine's FDA label of December 17, 2024 names quinidine in its drug interactions section; the quinidine label PlainMeds reads does not name donepezil/memantine.
Check it at the source: the donepezil/memantine FDA label on DailyMed (effective December 17, 2024, Amneal Pharmaceuticals NY LLC); the quinidine FDA label on DailyMed (effective February 1, 2018, Sun Pharmaceutical Industries, Inc.).
What does the donepezil/memantine label say about quinidine?
Donepezil/memantine label, drug interactionsDrugs on the Metabolism of Donepezil Inhibitors of CYP3A4 (e.g., ketoconazole) and CYP2D6 (e.g., quinidine), inhibit donepezil metabolism in vitro.
Source: FDA drug label (Memantine and Donepezil Hydrochlorides Extended-release), Amneal Pharmaceuticals NY LLC, effective December 17, 2024 (SPL set 2335950c-be3b-4248-ad04-e9763aee47d2), via openFDA; the full label on DailyMed
What does the quinidine label say about donepezil/memantine?
Quinidine's label (effective February 1, 2018) does not name donepezil/memantine 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
| Donepezil/memantine | Quinidine | |
|---|---|---|
| Labeled for | Alzheimer's disease | Atrial fibrillation |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $8.44 per unit 28-10 mg | $4.92 per tablet 324 mg tablet |
| Shortage now | A presentation being discontinued | 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