What the FDA labels say about taking them together
Digoxin and quinine
Digoxin's FDA label of December 5, 2024 names quinine in its drug interactions section, and quinine's label names digoxin too. The digoxin label: “Quinine; NA; 33%; Measure serum digoxin concentrations before initiating concomitant drugs. Reduce digoxin dose by approximately 15% to 30% or by modifying the dosing frequency and continue monitoring.”
Check it at the source: the digoxin FDA label on DailyMed (effective December 5, 2024, Advanz Pharma (US) Corp.); the quinine FDA label on DailyMed (effective November 9, 2023).
What does the digoxin label say about quinine?
Digoxin label, drug interactionsQuinine; NA; 33%; 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, NDA009330), Covis Pharma US, Inc, effective October 17, 2025 (SPL set 9ec84cac-6ecc-43dc-8006-6ccc029e2707), 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 quinine label say about digoxin?
Quinine label, drug interactions (prescription label)Digoxin Increased digoxin plasma concentration ( 5.8 , 7.1 ).
Quinine label, warnings and precautions (prescription label)If digoxin is used to prevent a rapid ventricular response, serum digoxin levels should be closely monitored, because digoxin levels may be increased with use of quinine [see DRUG INTERACTIONS ( 7.2 )].
Source: FDA drug label (Chininum sulphuricum), Boiron, effective November 9, 2023 (SPL set 33885950-2a55-11e7-8288-424c58303031), 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 | Quinine | |
|---|---|---|
| Labeled for | Heart failure, Atrial fibrillation | n/a |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $0.133 per tablet 125 mcg tablet | $0.698 per capsule 324 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