What the FDA labels say about taking them together
Dofetilide and triamterene
Dofetilide's FDA label of April 21, 2026 names triamterene in its contraindications section; the triamterene label PlainMeds reads does not name dofetilide. The dofetilide label: “The concomitant use of hydrochlorothiazide with TIKOSYN is contraindicated because this has been shown to significantly increase dofetilide plasma concentrations and QT interval prolongation.”
Check it at the source: the dofetilide FDA label on DailyMed (effective April 21, 2026, Pfizer Laboratories Div Pfizer Inc); the triamterene FDA label on DailyMed (effective December 5, 2024, Advanz Pharma (US) Corp.).
What does the dofetilide label say about triamterene?
Dofetilide label, contraindicationsThe concomitant use of hydrochlorothiazide (alone or in combinations such as with triamterene) with TIKOSYN is contraindicated (see PRECAUTIONS, Drug-Drug Interactions ) because this has been shown to significantly increase dofetilide plasma concentrations and QT interval prolongation.
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 triamterene label say about dofetilide?
Triamterene's label (effective December 5, 2024) does not name dofetilide in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Dyrenium), Advanz Pharma (US) Corp., effective December 5, 2024 (SPL set ebb177c0-d45d-4443-a85a-e76bd9931a42), 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
| Dofetilide | Triamterene | |
|---|---|---|
| Labeled for | Atrial fibrillation | Heart failure, Edema (fluid retention) |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.203 per capsule 125 mcg capsule | $5.98 per capsule 50 mg capsule |
| 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