What the FDA labels say about taking them together
Digoxin and ivacaftor
Ivacaftor's FDA label of March 23, 2026 names digoxin in its drug interactions section; the digoxin labels PlainMeds reads (3) do not name ivacaftor. The ivacaftor label: “Co-administration with digoxin, a sensitive P-gp substrate, increased digoxin exposure by 1.3-fold, consistent with weak inhibition of P-gp by ivacaftor.”
Check it at the source: the digoxin FDA label on DailyMed (effective December 5, 2024, Advanz Pharma (US) Corp.); the ivacaftor FDA label on DailyMed (effective March 23, 2026, Vertex Pharmaceuticals Incorporated).
What does the digoxin label say about ivacaftor?
Digoxin's label (effective December 5, 2024) and its 2 other brand-application labels do not name ivacaftor in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (LANOXIN), Advanz Pharma (US) Corp., effective December 5, 2024 (SPL set d91e3646-4c63-4512-ab22-db39c085c4dc), via openFDA; the full label on DailyMed
What does the ivacaftor label say about digoxin?
Ivacaftor label, drug interactionsCo-administration with digoxin, a sensitive P-gp substrate, increased digoxin exposure by 1.3-fold, consistent with weak inhibition of P-gp by ivacaftor.
Source: FDA drug label (Kalydeco), Vertex Pharmaceuticals Incorporated, effective March 23, 2026 (SPL set 0ab0c9f8-3eee-4e0f-9f3f-c1e16aaffe25), 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
| Digoxin | Ivacaftor | |
|---|---|---|
| Labeled for | Heart failure, Atrial fibrillation | n/a |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.133 per tablet 125 mcg tablet | n/a |
| 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