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What the FDA labels say about taking them together

Dofetilide and toremifene

Toremifene's FDA label of November 13, 2024 names dofetilide in its drug interactions section; the dofetilide 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 dofetilide FDA label on DailyMed (effective April 21, 2026, Pfizer Laboratories Div Pfizer Inc); the toremifene FDA label on DailyMed (effective November 13, 2024, Kyowa Kirin, Inc.).

What does the dofetilide label say about toremifene?

Dofetilide's label (effective April 21, 2026) 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 (Tikosyn), Pfizer Laboratories Div Pfizer Inc, effective April 21, 2026 (SPL set 02438044-d6a3-49e9-a1ac-3aad21ef2c8c), via openFDA; the full label on DailyMed

What does the toremifene label say about dofetilide?

Toremifene label, drug interactions

Agents 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

12Dofetilide generic labelers
2Toremifene generic labelers
DofetilideToremifene
Labeled forAtrial fibrillationBreast cancer
Boxed warningYesYes
Pharmacy cost (NADAC)$0.203 per capsule 125 mcg capsule$19.60 per tablet 60 mg tablet
Shortage nowNo current entryNo 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?