What the FDA labels say about taking them together
Quinidine and toremifene
Toremifene's FDA label of November 13, 2024 names quinidine in its drug interactions section; the quinidine label PlainMeds reads does not name toremifene. The toremifene label: “Agents generally accepted to prolong QT interval include Class 1A and Class III antiarrhythmics; certain antipsychotics; certain antidepressants; certain antibiotics; and certain anti-emetics.”
Check it at the source: the quinidine FDA label on DailyMed (effective February 1, 2018, Sun Pharmaceutical Industries, Inc.); the toremifene FDA label on DailyMed (effective November 13, 2024, Kyowa Kirin, Inc.).
What does the quinidine label say about toremifene?
Quinidine's label (effective February 1, 2018) does not name toremifene 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 toremifene label say about quinidine?
Toremifene label, drug interactionsAgents generally accepted to prolong QT interval include Class 1A (e.g., quinidine, procainamide, disopyramide) and Class III (e.g., amiodarone, sotalol, ibutilide, dofetilide) antiarrhythmics; certain antipsychotics (e.g., thioridazine, haloperidol); certain antidepressants (e.g., venlafaxine, amitriptyline); certain antibiotics (e.g., erythromycin, clarithromycin, levofloxacin, ofloxacin); and certain anti-emetics (e.g., ondansetron, granisetron).
Source: FDA drug label (Fareston), Kyowa Kirin, Inc., effective November 13, 2024 (SPL set 2cab8dd1-3a10-48e6-86ce-0e5275ed49e5), 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 | Toremifene | |
|---|---|---|
| Labeled for | Atrial fibrillation | Breast cancer |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $4.92 per tablet 324 mg tablet | $19.60 per tablet 60 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