What the FDA labels say about taking them together
Azithromycin and dofetilide
Azithromycin's FDA label of December 4, 2025 names dofetilide in its warnings and precautions section; the dofetilide label PlainMeds reads does not name azithromycin. The azithromycin label: “Providers should consider the risk of QT prolongation which can be fatal when weighing the risks and benefits of azithromycin for at-risk groups including: patients with known prolongation of the QT interval, a history …”
Check it at the source: the azithromycin FDA label on DailyMed (effective December 4, 2025, Bionpharma Inc.); the dofetilide FDA label on DailyMed (effective April 21, 2026, Pfizer Laboratories Div Pfizer Inc).
What does the azithromycin label say about dofetilide?
Azithromycin label, warnings and precautionsProviders should consider the risk of QT prolongation which can be fatal when weighing the risks and benefits of azithromycin for at-risk groups including: patients with known prolongation of the QT interval, a history of torsades de pointes, congenital long QT syndrome, bradyarrhythmias or uncompensated heart failure patients on drugs known to prolong the QT interval patients with ongoing proarrhythmic conditions such as uncorrected hypokalemia or hypomagnesemia, clinically significant bradycardia, and in patients receiving Class IA (quinidine, procainamide) or Class III (dofetilide, amiodarone, sotalol) antiarrhythmic agents.
Zithromax label (Pfizer Laboratories Div Pfizer Inc, July 24, 2026), warnings and precautionspatients with ongoing proarrhythmic conditions such as uncorrected hypokalemia or hypomagnesemia, clinically significant bradycardia, and in patients receiving Class IA (quinidine, procainamide) or Class III (dofetilide, amiodarone, sotalol) antiarrhythmic agents.
Source: FDA drug label (Zithromax, NDA050711), Pfizer Laboratories Div Pfizer Inc, effective July 24, 2026 (SPL set db52b91e-79f7-4cc1-9564-f2eee8e31c45), via openFDA
Source: FDA drug label (Azithromycin), Bionpharma Inc., effective December 4, 2025 (SPL set 859bb02c-a4bc-46fa-9fc9-def1219b5dfb), via openFDA; the full label on DailyMed
What does the dofetilide label say about azithromycin?
Dofetilide's label (effective April 21, 2026) does not name azithromycin 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
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
| Azithromycin | Dofetilide | |
|---|---|---|
| Labeled for | Bacterial infections | Atrial fibrillation |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $0.266 per tablet 250 mg tablet | $0.203 per capsule 125 mcg capsule |
| 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