What the FDA labels say about taking them together
Digoxin and diltiazem
Digoxin's FDA label of December 5, 2024 names diltiazem in its drug interactions section, and diltiazem's label names digoxin too. The diltiazem label: “Administration of CARDIZEM with digoxin in 24 healthy male subjects increased plasma digoxin concentrations approximately 20%.”
Check it at the source: the digoxin FDA label on DailyMed (effective December 5, 2024, Advanz Pharma (US) Corp.); the diltiazem FDA label on DailyMed (effective August 7, 2026, Bausch Health US, LLC).
What does the digoxin label say about diltiazem?
Digoxin label, drug interactionsDiltiazem; 20%; NA; Measure serum digoxin concentrations before initiating concomitant drugs. Reduce digoxin concentrations by decreasing the dose by approximately 15-30% or by modifying the dosing frequency and continue monitoring.
Source: FDA drug label (Digoxin, NDA021648), Hikma Pharmaceuticals USA Inc., effective April 10, 2025 (SPL set 1b7e5c6e-e052-41b0-a4ce-05dfe62faaaf), via openFDA
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 diltiazem label say about digoxin?
Diltiazem label, drug interactionsAdministration of diltiazem hydrochloride with digoxin in 24 healthy male subjects increased plasma digoxin concentrations approximately 20%.
Source: FDA drug label (Cardizem, NDA018602), Bausch Health US LLC, effective April 30, 2025 (SPL set f3e7ecef-f360-4987-a4f5-933214130ab2), via openFDA
Source: FDA drug label (TIAZAC EXTENDED RELEASE), Bausch Health US, LLC, effective August 7, 2026 (SPL set c567fe7e-887e-4291-a0d1-2dd3f25cbf25), 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 | Diltiazem | |
|---|---|---|
| Labeled for | Heart failure, Atrial fibrillation | High blood pressure, Angina, Atrial fibrillation |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.133 per tablet 125 mcg tablet | $0.144 per capsule 24h ER(cd) 120 mg capsule |
| Shortage now | No current entry | A presentation being discontinued |
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